diff --git a/GPS/GPS.bin b/GPS/GPS.bin
new file mode 100755
index 0000000..e2a9967
Binary files /dev/null and b/GPS/GPS.bin differ
diff --git a/GPS/GPS.c b/GPS/GPS.c
new file mode 100644
index 0000000..cecc433
--- /dev/null
+++ b/GPS/GPS.c
@@ -0,0 +1,228 @@
+/*
+ * GPS.c
+ *
+ * Copyright 2015 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#include "main.h"
+#include "GPS.h"
+#include "uart.h"
+
+#define GPS_endline() do{GPS_send_string((uint8_t*)"\r\n");}while(0)
+#define U(arg)  ((uint8_t*)arg)
+
+
+void GPS_send_string(uint8_t *str){
+	while(*str)
+		fill_uart_buff(USART2, *str++);
+}
+
+int strncmp(const uint8_t *one, const uint8_t *two, int n){
+	int diff = 0;
+	do{
+		diff = (int)(*one++) - (int)(*two++);
+	}while(--n && diff == 0);
+	return diff;
+}
+
+uint8_t *ustrchr(uint8_t *str, uint8_t symbol){
+//	uint8_t *ptr = str;
+	do{
+		if(*str == symbol) return str;
+	}while(*(++str));
+	return NULL;
+}
+
+/*
+// Check checksum
+int checksum(uint8_t *buf){
+	uint8_t *eol;
+	char chs[3];
+	uint8_t checksum = 0;
+	if(*buf != '$' || !(eol = (uint8_t*)ustrchr((char*)buf, '*'))){
+		DBG("Wrong data: %s\n", buf);
+		return 0;
+	}
+	while(++buf != eol)
+		checksum ^= *buf;
+	snprintf(chs, 3, "%02X", checksum);
+	if(strncmp(chs, (char*)++buf, 2)){
+		DBG("Wrong checksum: %s", chs);
+		return 0;
+	}
+	return 1;
+}*/
+
+void send_chksum(uint8_t chs){
+	void puts(uint8_t c){
+		if(c < 10)
+			fill_uart_buff(USART2, c + '0');
+		else
+			fill_uart_buff(USART2, c + 'A' - 10);
+	}
+	puts(chs >> 4);
+	puts(chs & 0x0f);
+}
+/**
+ * Calculate checksum & write message to port
+ * @param  buf - command to write (with leading $ and trailing *)
+ * return 0 if fails
+ */
+void write_with_checksum(uint8_t *buf){
+	uint8_t checksum = 0;
+	GPS_send_string(buf);
+	++buf; // skip leaders
+	do{
+		checksum ^= *buf++;
+	}while(*buf && *buf != '*');
+	send_chksum(checksum);
+	GPS_endline();
+}
+
+/**
+ * set rate for given NMEA field
+ * @param field - name of NMEA field
+ * @param rate  - rate in seconds (0 disables field)
+ * @return -1 if fails, rate if OK
+ */
+void block_field(const uint8_t *field){
+	uint8_t buf[22];
+	memcpy(buf, U("$PUBX,40,"), 9);
+	memcpy(buf+9, field, 3);
+	memcpy(buf+12, U(",0,0,0,0*"), 9);
+	buf[21] = 0;
+	write_with_checksum(buf);
+}
+
+
+/**
+ * Send starting sequences (get only RMC messages)
+ */
+void GPS_send_start_seq(){
+	const uint8_t *GPmsgs[5] = {U("GSV"), U("GSA"), U("GGA"), U("GLL"), U("VTG")};
+	int i;
+	for(i = 0; i < 5; ++i)
+		block_field(GPmsgs[i]);
+}
+/*
+uint8_t *nextpos(uint8_t **buf, int pos){
+	int i;
+	if(pos < 1) pos = 1;
+	for(i = 0; i < pos; ++i){
+		*buf = ustrchr(*buf, ',');
+		if(!*buf) break;
+		++(*buf);
+	}
+	return *buf;
+}
+#define NEXT()      do{if(!nextpos(&buf, 1)) goto ret;}while(0)
+#define SKIP(NPOS)  do{if(!nextpos(&buf, NPOS)) goto ret;}while(0)
+*/
+/**
+ * Parse answer from GPS module
+ */
+void GPS_parse_answer(uint8_t *buf){
+	uint8_t *ptr;
+	DBG(buf);
+	if(strncmp(buf+3, U("RMC"), 3)) return; // not RMC message
+	buf += 7; // skip header
+	P("time: ");
+	if(*buf != ','){
+		ptr = ustrchr(buf, ',');
+		*ptr++ = 0;
+		P(buf);
+		buf = ptr;
+		P(" ");
+	}else{
+		P("undefined ");
+		++buf;
+	}
+	P("\n");
+}
+
+/*
+
+void rmc(uint8_t *buf){
+	//DBG("rmc: %s\n", buf);
+	int H, M, LO, LA, d, m, y, getdate = 0;
+	double S, longitude, lattitude, speed, track, mag;
+	char varn = 'V', north = '0', east = '0', mageast = '0', mode = 'N';
+	sscanf((char*)buf, "%2d%2d%lf", &H, &M, &S);
+	NEXT();
+	if(*buf != ',') varn = *buf;
+	if(varn != 'A')
+		PRINT("(data could be wrong)");
+	else{
+		PRINT("(data valid)");
+		if(GP->date) getdate = 1; // as only we have valid data we show it to user
+	}
+	PRINT(" time: %02d:%02d:%05.2f", H, M, S);
+	PRINT(" timediff: %g", timediff(H, M, S));
+	NEXT();
+	sscanf((char*)buf, "%2d%lf", &LA, &lattitude);
+	NEXT();
+	if(*buf != ','){
+		north = *buf;
+		lattitude = (double)LA + lattitude / 60.;
+		if(north == 'S') lattitude = -lattitude;
+		PRINT(" latt: %g", lattitude);
+		Latt_mean += lattitude;
+		Latt_sq += lattitude*lattitude;
+		++Latt_N;
+	}
+	NEXT();
+	sscanf((char*)buf, "%3d%lf", &LO, &longitude);
+	NEXT();
+	if(*buf != ','){
+		east = *buf;
+		longitude = (double)LO + longitude / 60.;
+		if(east == 'W') longitude = -longitude;
+		PRINT(" long: %g", longitude);
+		Long_mean += longitude;
+		Long_sq += longitude*longitude;
+		++Long_N;
+	}
+	NEXT();
+	if(*buf != ','){
+		sscanf((char*)buf, "%lf", &speed);
+		PRINT(" speed: %gknots", speed);
+	}
+	NEXT();
+	if(*buf != ','){
+		sscanf((char*)buf, "%lf", &track);
+		PRINT(" track: %gdeg,True", track);
+	}
+	NEXT();
+	if(sscanf((char*)buf, "%2d%2d%2d", &d, &m, &y) == 3)
+		PRINT(" date(dd/mm/yy): %02d/%02d/%02d", d, m, y);
+	if(getdate) show_date(H,M,S,d,m,y); // show date & exit
+	NEXT();
+	sscanf((char*)buf, "%lf,%c", &mag, &mageast);
+	if(mageast == 'E' || mageast == 'W'){
+		if(mageast == 'W') mag = -mag;
+		PRINT(" magnetic var: %g", mag);
+	}
+	SKIP(2);
+	if(*buf != ','){
+		mode = *buf;
+		PRINT(" mode: %c", mode);
+	}
+ret:
+	PRINT("\n");
+}
+*/
diff --git a/GPS/GPS.geany b/GPS/GPS.geany
new file mode 100644
index 0000000..d6ec8a5
--- /dev/null
+++ b/GPS/GPS.geany
@@ -0,0 +1,36 @@
+[file_prefs]
+final_new_line=true
+ensure_convert_new_lines=true
+strip_trailing_spaces=true
+replace_tabs=false
+
+[indentation]
+indent_width=4
+indent_type=1
+indent_hard_tab_width=4
+detect_indent=false
+detect_indent_width=false
+indent_mode=3
+
+[project]
+name=GPS
+base_path=/home/eddy/Docs/SAO/ELECTRONICS/STM32/c8t6/GPS/
+
+[long line marker]
+long_line_behaviour=1
+long_line_column=80
+
+[files]
+current_page=1
+FILE_NAME_0=4732;C;0;EUTF-8;1;1;0;%2Fhome%2Feddy%2FDocs%2FSAO%2FELECTRONICS%2FSTM32%2Fc8t6%2FGPS%2Fuser_proto.c;0;4
+FILE_NAME_1=0;C;0;EUTF-8;1;1;0;%2Fhome%2Feddy%2FDocs%2FSAO%2FELECTRONICS%2FSTM32%2Fc8t6%2FGPS%2Fuser_proto.h;0;4
+FILE_NAME_2=6683;C;0;EUTF-8;1;1;0;%2Fhome%2Feddy%2FDocs%2FSAO%2FELECTRONICS%2FSTM32%2Fc8t6%2FGPS%2Fuart.c;0;4
+FILE_NAME_3=1297;C;0;EUTF-8;1;1;0;%2Fhome%2Feddy%2FDocs%2FSAO%2FELECTRONICS%2FSTM32%2Fc8t6%2FGPS%2Fuart.h;0;4
+FILE_NAME_4=2072;C;0;EUTF-8;1;1;0;%2Fhome%2Feddy%2FDocs%2FSAO%2FELECTRONICS%2FSTM32%2Fc8t6%2FGPS%2Fmain.c;0;4
+FILE_NAME_5=1364;C;0;EUTF-8;1;1;0;%2Fhome%2Feddy%2FDocs%2FSAO%2FELECTRONICS%2FSTM32%2Fc8t6%2FGPS%2Fmain.h;0;4
+FILE_NAME_6=949;C;0;EUTF-8;1;1;0;%2Fhome%2Feddy%2FDocs%2FSAO%2FELECTRONICS%2FSTM32%2Fc8t6%2FGPS%2FGPS.c;0;4
+FILE_NAME_7=903;C;0;EUTF-8;1;1;0;%2Fhome%2Feddy%2FDocs%2FSAO%2FELECTRONICS%2FSTM32%2Fc8t6%2FGPS%2FGPS.h;0;4
+FILE_NAME_8=2128;C;0;EUTF-8;1;1;0;%2Fhome%2Feddy%2FDocs%2FSAO%2FELECTRONICS%2FSTM32%2Fc8t6%2FGPS%2Fhardware_ini.c;0;4
+
+[VTE]
+last_dir=/home/eddy/Docs/SAO/Cameras/FLI_camera/my/Mytakepic
diff --git a/GPS/GPS.h b/GPS/GPS.h
new file mode 100644
index 0000000..6ce2330
--- /dev/null
+++ b/GPS/GPS.h
@@ -0,0 +1,29 @@
+/*
+ * GPS.h
+ *
+ * Copyright 2015 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#pragma once
+#ifndef __GPS_H__
+#define __GPS_H__
+
+void GPS_parse_answer(uint8_t *string);
+void GPS_send_start_seq();
+
+#endif // __GPS_H__
diff --git a/GPS/Makefile b/GPS/Makefile
new file mode 100644
index 0000000..18f7a20
--- /dev/null
+++ b/GPS/Makefile
@@ -0,0 +1,133 @@
+BINARY		= GPS
+BOOTPORT	?= /dev/ttyUSB0
+BOOTSPEED	?= 115200
+# change this linking script depending on particular MCU model,
+# for example, if you have STM32F103VBT6, you should write:
+LDSCRIPT	= ld/stm32f103x8.ld
+LIBNAME		= opencm3_stm32f1
+DEFS		= -DSTM32F1 -DEBUG
+
+OBJDIR = mk
+INDEPENDENT_HEADERS=
+
+FP_FLAGS	?= -msoft-float
+ARCH_FLAGS	= -mthumb -mcpu=cortex-m3 $(FP_FLAGS) -mfix-cortex-m3-ldrd
+
+###############################################################################
+# Executables
+PREFIX		?= arm-none-eabi
+
+RM			:= rm -f
+RMDIR		:= rmdir
+CC			:= $(PREFIX)-gcc
+LD			:= $(PREFIX)-gcc
+AR			:= $(PREFIX)-ar
+AS			:= $(PREFIX)-as
+OBJCOPY		:= $(PREFIX)-objcopy
+OBJDUMP		:= $(PREFIX)-objdump
+GDB			:= $(PREFIX)-gdb
+STFLASH		= $(shell which st-flash)
+STBOOT		= $(shell which stm32flash)
+
+###############################################################################
+# Source files
+LDSCRIPT	?= $(BINARY).ld
+SRC			= $(wildcard *.c)
+OBJS		= $(addprefix $(OBJDIR)/, $(SRC:%.c=%.o))
+
+ifeq ($(strip $(OPENCM3_DIR)),)
+OPENCM3_DIR := /usr/local/arm-none-eabi
+$(info Using $(OPENCM3_DIR) path to library)
+endif
+
+INCLUDE_DIR	= $(OPENCM3_DIR)/include
+LIB_DIR		= $(OPENCM3_DIR)/lib
+SCRIPT_DIR	= $(OPENCM3_DIR)/scripts
+
+###############################################################################
+# C flags
+CFLAGS		+= -Os -g
+CFLAGS		+= -Wall -Wextra -Wshadow -Wimplicit-function-declaration
+CFLAGS		+= -Wredundant-decls
+# -Wmissing-prototypes -Wstrict-prototypes
+CFLAGS		+= -fno-common -ffunction-sections -fdata-sections
+
+###############################################################################
+# C & C++ preprocessor common flags
+CPPFLAGS	+= -MD
+CPPFLAGS	+= -Wall -Werror
+CPPFLAGS	+= -I$(INCLUDE_DIR) $(DEFS)
+
+###############################################################################
+# Linker flags
+LDFLAGS		+= --static -nostartfiles
+LDFLAGS		+= -L$(LIB_DIR)
+LDFLAGS		+= -T$(LDSCRIPT)
+LDFLAGS		+= -Wl,-Map=$(*).map
+LDFLAGS		+= -Wl,--gc-sections
+
+###############################################################################
+# Used libraries
+LDLIBS		+= -l$(LIBNAME)
+LDLIBS		+= -Wl,--start-group -lc -lgcc -Wl,--end-group
+
+.SUFFIXES: .elf .bin .hex .srec .list .map .images
+.SECONDEXPANSION:
+.SECONDARY:
+
+ELF		:= $(OBJDIR)/$(BINARY).elf
+LIST	:= $(OBJDIR)/$(BINARY).list
+BIN		:= $(BINARY).bin
+HEX		:= $(BINARY).hex
+
+all: bin
+
+elf: $(ELF)
+bin: $(BIN)
+hex: $(HEX)
+list: $(LIST)
+
+$(OBJDIR):
+	mkdir $(OBJDIR)
+
+$(OBJDIR)/%.o: %.c
+	@printf "  CC      $<\n"
+	$(CC) $(CFLAGS) $(CPPFLAGS) $(ARCH_FLAGS) -o $@ -c $<
+
+$(SRC) : %.c : %.h $(INDEPENDENT_HEADERS)
+	@touch $@
+
+%.h: ;
+
+$(BIN): $(ELF)
+	@printf "  OBJCOPY $(BIN)\n"
+	$(OBJCOPY) -Obinary $(ELF) $(BIN)
+
+$(HEX): $(ELF)
+	@printf "  OBJCOPY $(HEX)\n"
+	$(OBJCOPY) -Oihex $(ELF) $(HEX)
+
+$(LIST): $(ELF)
+	@printf "  OBJDUMP $(LIST)\n"
+	$(OBJDUMP) -S $(ELF) > $(LIST)
+
+$(ELF): $(OBJDIR) $(OBJS) $(LDSCRIPT) $(LIB_DIR)/lib$(LIBNAME).a
+	@printf "  LD      $(ELF)\n"
+	$(LD) $(LDFLAGS) $(ARCH_FLAGS) $(OBJS) $(LDLIBS) -o $(ELF)
+
+clean:
+	@printf "  CLEAN\n"
+	$(RM) $(OBJS) $(OBJDIR)/*.d $(ELF) $(HEX) $(LIST) $(OBJDIR)/*.map
+	$(RMDIR) $(OBJDIR)
+
+flash: $(BIN)
+	@printf "  FLASH  $(BIN)\n"
+	$(STFLASH) write $(BIN) 0x8000000
+
+boot: $(BIN)
+	@printf "  LOAD $(BIN) through bootloader\n"
+	$(STBOOT) -b$(BOOTSPEED) $(BOOTPORT) -w $(BIN)
+
+.PHONY: clean elf hex list flash boot
+
+#-include $(OBJS:.o=.d)
diff --git a/GPS/README b/GPS/README
new file mode 100644
index 0000000..d525426
--- /dev/null
+++ b/GPS/README
@@ -0,0 +1,8 @@
+NOT READY!
+
+GPS RTC
+
+written for chinese devboard based on STM32F103RBT6
+
+Press H for help
+
diff --git a/GPS/cdcacm.c b/GPS/cdcacm.c
new file mode 100644
index 0000000..5f032ad
--- /dev/null
+++ b/GPS/cdcacm.c
@@ -0,0 +1,314 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2010 Gareth McMullin <gareth@blacksphere.co.nz>
+ * Copyright 2014 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "cdcacm.h"
+#include "user_proto.h"
+#include "main.h"
+
+// Buffer for USB Tx
+static uint8_t USB_Tx_Buffer[USB_TX_DATA_SIZE];
+static uint8_t USB_Tx_ptr = 0;
+// connection flag
+uint8_t USB_connected = 0;
+static const struct usb_device_descriptor dev = {
+	.bLength = USB_DT_DEVICE_SIZE,
+	.bDescriptorType = USB_DT_DEVICE,
+	.bcdUSB = 0x0200,
+	.bDeviceClass = USB_CLASS_CDC,
+	.bDeviceSubClass = 0,
+	.bDeviceProtocol = 0,
+	.bMaxPacketSize0 = 64,
+	.idVendor = 0x0483,
+	.idProduct = 0x5740,
+	.bcdDevice = 0x0200,
+	.iManufacturer = 1,
+	.iProduct = 2,
+	.iSerialNumber = 3,
+	.bNumConfigurations = 1,
+};
+
+char usbdatabuf[USB_RX_DATA_SIZE]; // buffer for received data
+int usbdatalen = 0;  // lenght of received data
+
+/*
+ * This notification endpoint isn't implemented. According to CDC spec its
+ * optional, but its absence causes a NULL pointer dereference in Linux
+ * cdc_acm driver.
+ */
+static const struct usb_endpoint_descriptor comm_endp[] = {{
+	.bLength = USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType = USB_DT_ENDPOINT,
+	.bEndpointAddress = 0x83,
+	.bmAttributes = USB_ENDPOINT_ATTR_INTERRUPT,
+	.wMaxPacketSize = 16,
+	.bInterval = 255,
+}};
+
+static const struct usb_endpoint_descriptor data_endp[] = {{
+	.bLength = USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType = USB_DT_ENDPOINT,
+	.bEndpointAddress = 0x01,
+	.bmAttributes = USB_ENDPOINT_ATTR_BULK,
+	.wMaxPacketSize = 64,
+	.bInterval = 1,
+}, {
+	.bLength = USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType = USB_DT_ENDPOINT,
+	.bEndpointAddress = 0x82,
+	.bmAttributes = USB_ENDPOINT_ATTR_BULK,
+	.wMaxPacketSize = 64,
+	.bInterval = 1,
+}};
+
+static const struct {
+	struct usb_cdc_header_descriptor header;
+	struct usb_cdc_call_management_descriptor call_mgmt;
+	struct usb_cdc_acm_descriptor acm;
+	struct usb_cdc_union_descriptor cdc_union;
+} __attribute__((packed)) cdcacm_functional_descriptors = {
+	.header = {
+		.bFunctionLength = sizeof(struct usb_cdc_header_descriptor),
+		.bDescriptorType = CS_INTERFACE,
+		.bDescriptorSubtype = USB_CDC_TYPE_HEADER,
+		.bcdCDC = 0x0110,
+	},
+	.call_mgmt = {
+		.bFunctionLength =
+			sizeof(struct usb_cdc_call_management_descriptor),
+		.bDescriptorType = CS_INTERFACE,
+		.bDescriptorSubtype = USB_CDC_TYPE_CALL_MANAGEMENT,
+		.bmCapabilities = 0,
+		.bDataInterface = 1,
+	},
+	.acm = {
+		.bFunctionLength = sizeof(struct usb_cdc_acm_descriptor),
+		.bDescriptorType = CS_INTERFACE,
+		.bDescriptorSubtype = USB_CDC_TYPE_ACM,
+		.bmCapabilities = 0,
+	},
+	.cdc_union = {
+		.bFunctionLength = sizeof(struct usb_cdc_union_descriptor),
+		.bDescriptorType = CS_INTERFACE,
+		.bDescriptorSubtype = USB_CDC_TYPE_UNION,
+		.bControlInterface = 0,
+		.bSubordinateInterface0 = 1,
+	 },
+};
+
+static const struct usb_interface_descriptor comm_iface[] = {{
+	.bLength = USB_DT_INTERFACE_SIZE,
+	.bDescriptorType = USB_DT_INTERFACE,
+	.bInterfaceNumber = 0,
+	.bAlternateSetting = 0,
+	.bNumEndpoints = 1,
+	.bInterfaceClass = USB_CLASS_CDC,
+	.bInterfaceSubClass = USB_CDC_SUBCLASS_ACM,
+	.bInterfaceProtocol = USB_CDC_PROTOCOL_AT,
+	.iInterface = 0,
+
+	.endpoint = comm_endp,
+
+	.extra = &cdcacm_functional_descriptors,
+	.extralen = sizeof(cdcacm_functional_descriptors),
+}};
+
+static const struct usb_interface_descriptor data_iface[] = {{
+	.bLength = USB_DT_INTERFACE_SIZE,
+	.bDescriptorType = USB_DT_INTERFACE,
+	.bInterfaceNumber = 1,
+	.bAlternateSetting = 0,
+	.bNumEndpoints = 2,
+	.bInterfaceClass = USB_CLASS_DATA,
+	.bInterfaceSubClass = 0,
+	.bInterfaceProtocol = 0,
+	.iInterface = 0,
+
+	.endpoint = data_endp,
+}};
+
+static const struct usb_interface ifaces[] = {{
+	.num_altsetting = 1,
+	.altsetting = comm_iface,
+}, {
+	.num_altsetting = 1,
+	.altsetting = data_iface,
+}};
+
+static const struct usb_config_descriptor config = {
+	.bLength = USB_DT_CONFIGURATION_SIZE,
+	.bDescriptorType = USB_DT_CONFIGURATION,
+	.wTotalLength = 0,
+	.bNumInterfaces = 2,
+	.bConfigurationValue = 1,
+	.iConfiguration = 0,
+	.bmAttributes = 0x80,
+	.bMaxPower = 0x32,
+
+	.interface = ifaces,
+};
+
+static const char *usb_strings[] = {
+	"Organisation, author",
+	"device",
+	"version",
+};
+
+// default line coding: B115200, 1stop, 8bits, parity none
+struct usb_cdc_line_coding linecoding = {
+	.dwDTERate   = 115200,
+	.bCharFormat = USB_CDC_1_STOP_BITS,
+	.bParityType = USB_CDC_NO_PARITY,
+	.bDataBits   = 8,
+};
+
+/* Buffer to be used for control requests. */
+uint8_t usbd_control_buffer[128];
+
+/**
+ * This function runs every time it gets a request for control parameters get/set
+ * parameter SET_LINE_CODING used to change USART1 parameters: if you want to
+ * change them, just connect through USB with required parameters
+ */
+static int cdcacm_control_request(usbd_device *usbd_dev, struct usb_setup_data *req, uint8_t **buf,
+		uint16_t *len, void (**complete)(usbd_device *usbd_dev, struct usb_setup_data *req)){
+	(void)complete;
+	(void)buf;
+	(void)usbd_dev;
+	char local_buf[10];
+	struct usb_cdc_line_coding  lc;
+
+	switch (req->bRequest) {
+	case SET_CONTROL_LINE_STATE:{
+		if(req->wValue){ // terminal is opened
+			USB_connected = 1;
+		}else{ // terminal is closed
+			USB_connected = 0;
+		}
+		/*
+		 * This Linux cdc_acm driver requires this to be implemented
+		 * even though it's optional in the CDC spec, and we don't
+		 * advertise it in the ACM functional descriptor.
+		 */
+		struct usb_cdc_notification *notif = (void *)local_buf;
+		/* We echo signals back to host as notification. */
+		notif->bmRequestType = 0xA1;
+		notif->bNotification = USB_CDC_NOTIFY_SERIAL_STATE;
+		notif->wValue = 0;
+		notif->wIndex = 0;
+		notif->wLength = 2;
+		local_buf[8] = req->wValue & 3;
+		local_buf[9] = 0;
+		usbd_ep_write_packet(usbd_dev, 0x83, local_buf, 10);
+	}break;
+	case SET_LINE_CODING:
+		if (!len || (*len != sizeof(struct usb_cdc_line_coding)))
+			return 0;
+		memcpy((void *)&lc, (void *)*buf, *len);
+		// Mark & Space parity don't support by hardware, check it
+		if(lc.bParityType == USB_CDC_MARK_PARITY || lc.bParityType == USB_CDC_SPACE_PARITY){
+			return 0; // error
+		}else{
+//			memcpy((void *)&linecoding, (void *)&lc, sizeof(struct usb_cdc_line_coding));
+//			UART_setspeed(USART1, &linecoding);
+		}
+	break;
+	case GET_LINE_CODING: // return linecoding buffer
+		if(len && *len == sizeof(struct usb_cdc_line_coding))
+			memcpy((void *)*buf, (void *)&linecoding, sizeof(struct usb_cdc_line_coding));
+		//usbd_ep_write_packet(usbd_dev, 0x83, (char*)&linecoding, sizeof(linecoding));
+	break;
+	default:
+		return 0;
+	}
+	return 1;
+}
+
+static void cdcacm_data_rx_cb(usbd_device *usbd_dev, uint8_t ep){
+	(void)ep;
+	int len = usbd_ep_read_packet(usbd_dev, 0x01, usbdatabuf + usbdatalen, USB_RX_DATA_SIZE - usbdatalen);
+	usbdatalen += len;
+	if(usbdatalen >= USB_RX_DATA_SIZE){ // buffer overflow - drop all its contents
+		usbdatalen = 0;
+	}
+}
+
+static void cdcacm_data_tx_cb(usbd_device *usbd_dev, uint8_t ep){
+	(void)ep;
+	(void)usbd_dev;
+
+	usb_send_buffer();
+}
+
+static void cdcacm_set_config(usbd_device *usbd_dev, uint16_t wValue)
+{
+	(void)wValue;
+	(void)usbd_dev;
+
+	usbd_ep_setup(usbd_dev, 0x01, USB_ENDPOINT_ATTR_BULK, USB_RX_DATA_SIZE, cdcacm_data_rx_cb);
+	usbd_ep_setup(usbd_dev, 0x82, USB_ENDPOINT_ATTR_BULK, USB_TX_DATA_SIZE, cdcacm_data_tx_cb);
+	usbd_ep_setup(usbd_dev, 0x83, USB_ENDPOINT_ATTR_INTERRUPT, 16, NULL);
+
+	usbd_register_control_callback(
+				usbd_dev,
+				USB_REQ_TYPE_CLASS | USB_REQ_TYPE_INTERFACE,
+				USB_REQ_TYPE_TYPE | USB_REQ_TYPE_RECIPIENT,
+				cdcacm_control_request);
+}
+
+static usbd_device *current_usb = NULL;
+
+usbd_device *USB_init(){
+	current_usb = usbd_init(&stm32f103_usb_driver, &dev, &config,
+		usb_strings, 3, usbd_control_buffer, sizeof(usbd_control_buffer));
+	if(!current_usb) return NULL;
+	usbd_register_set_config_callback(current_usb, cdcacm_set_config);
+	return current_usb;
+}
+
+mutex_t send_block_mutex = MUTEX_UNLOCKED;
+/**
+ * Put byte into USB buffer to send
+ * @param byte - a byte to put into a buffer
+ */
+void usb_send(uint8_t byte){
+	mutex_lock(&send_block_mutex);
+	USB_Tx_Buffer[USB_Tx_ptr++] = byte;
+	mutex_unlock(&send_block_mutex);
+	if(USB_Tx_ptr == USB_TX_DATA_SIZE){ // buffer can be overflowed - send it!
+		usb_send_buffer();
+	}
+}
+
+/**
+ * Send all data in buffer over USB
+ * this function runs when buffer is full or on SysTick
+ */
+void usb_send_buffer(){
+	if(MUTEX_LOCKED == mutex_trylock(&send_block_mutex)) return;
+	if(USB_Tx_ptr){
+		if(current_usb && USB_connected){
+			// usbd_ep_write_packet return 0 if previous packet isn't transmit yet
+			while(USB_Tx_ptr != usbd_ep_write_packet(current_usb, 0x82, USB_Tx_Buffer, USB_Tx_ptr));
+			usbd_poll(current_usb);
+		}
+		USB_Tx_ptr = 0;
+	}
+	mutex_unlock(&send_block_mutex);
+}
diff --git a/GPS/cdcacm.h b/GPS/cdcacm.h
new file mode 100644
index 0000000..1051d83
--- /dev/null
+++ b/GPS/cdcacm.h
@@ -0,0 +1,54 @@
+/*
+ * ccdcacm.h
+ *
+ * Copyright 2014 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#pragma once
+#ifndef __CCDCACM_H__
+#define __CCDCACM_H__
+
+#include <libopencm3/usb/usbd.h>
+
+// commands through EP0
+#define SEND_ENCAPSULATED_COMMAND   0x00
+#define GET_ENCAPSULATED_RESPONSE   0x01
+#define SET_COMM_FEATURE            0x02
+#define GET_COMM_FEATURE            0x03
+#define CLEAR_COMM_FEATURE          0x04
+#define SET_LINE_CODING             0x20
+#define GET_LINE_CODING             0x21
+#define SET_CONTROL_LINE_STATE      0x22
+#define SEND_BREAK                  0x23
+
+// Size of input/output buffers
+#define USB_TX_DATA_SIZE            64
+#define USB_RX_DATA_SIZE            64
+
+// USB connection flag
+extern uint8_t USB_connected;
+extern struct usb_cdc_line_coding linecoding;
+
+extern char usbdatabuf[];
+extern int usbdatalen;
+
+usbd_device *USB_init();
+void usb_send(uint8_t byte);
+void usb_send_buffer();
+
+#endif // __CCDCACM_H__
diff --git a/GPS/hardware_ini.c b/GPS/hardware_ini.c
new file mode 100644
index 0000000..887faab
--- /dev/null
+++ b/GPS/hardware_ini.c
@@ -0,0 +1,96 @@
+/*
+ * hardware_ini.c - functions for HW initialisation
+ *
+ * Copyright 2014 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+/*
+ * All hardware-dependent initialisation & definition should be placed here
+ * and in hardware_ini.h
+ *
+ */
+
+#include "main.h"
+#include "hardware_ini.h"
+
+/**
+ * GPIO initialisaion: clocking + pins setup
+ */
+void GPIO_init(){
+/*	rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPAEN |
+			RCC_APB2ENR_IOPBEN | RCC_APB2ENR_IOPCEN | RCC_APB2ENR_IOPDEN |
+			RCC_APB2ENR_IOPEEN);
+	// Buttons: pull-up input
+	gpio_set_mode(BTNS_PORT, GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN,
+			BTN_S2_PIN | BTN_S3_PIN);
+	// turn on pull-up
+	gpio_set(BTNS_PORT, BTN_S2_PIN | BTN_S3_PIN);
+	// LEDS: opendrain output
+	gpio_set_mode(LEDS_PORT, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_OPENDRAIN,
+			LED_D1_PIN | LED_D2_PIN);
+	// turn off LEDs
+	gpio_set(LEDS_PORT, LED_D1_PIN | LED_D2_PIN);*/
+/*
+	// USB_DISC: push-pull
+	gpio_set_mode(USB_DISC_PORT, GPIO_MODE_OUTPUT_2_MHZ,
+				GPIO_CNF_OUTPUT_PUSHPULL, USB_DISC_PIN);
+	// USB_POWER: open drain, externall pull down with R7 (22k)
+	gpio_set_mode(USB_POWER_PORT, GPIO_MODE_INPUT,
+				GPIO_CNF_INPUT_FLOAT, USB_POWER_PIN);
+*/
+}
+
+/*
+ * SysTick used for system timer with period of 1ms
+ */
+void SysTick_init(){
+	systick_set_clocksource(STK_CSR_CLKSOURCE_AHB_DIV8); // Systyck: 72/8=9MHz
+	systick_set_reload(899); // 900 pulses: 10kHz
+	systick_interrupt_enable();
+	systick_counter_enable();
+}
+
+/*
+// check buttons S2/S3
+void check_btns(){
+	static uint8_t oldstate[2] = {1,1}; // old buttons state
+	uint8_t newstate[2], i;
+	static uint32_t Old_timer[2] = {0,0};
+	newstate[0] = gpio_get(BTNS_PORT, BTN_S2_PIN) ? 1 : 0;
+	newstate[1] = gpio_get(BTNS_PORT, BTN_S3_PIN) ? 1 : 0;
+	for(i = 0; i < 2; i++){
+		uint8_t new = newstate[i];
+		// pause for 60ms
+		uint32_t O = Old_timer[i];
+		if(O){
+			if(Timer - O > 60 || O > Timer){
+				P("Button S");
+				usb_send('2' + i);
+				if(new) P("released");
+				else P("pressed");
+				newline();
+				oldstate[i] = new;
+				Old_timer[i] = 0;
+			}
+		}
+		else if(new != oldstate[i]){
+			Old_timer[i] = Timer;
+		}
+	}
+}
+*/
diff --git a/GPS/hardware_ini.h b/GPS/hardware_ini.h
new file mode 100644
index 0000000..ff0311f
--- /dev/null
+++ b/GPS/hardware_ini.h
@@ -0,0 +1,76 @@
+/*
+ * hardware_ini.h
+ *
+ * Copyright 2014 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#pragma once
+#ifndef __HARDWARE_INI_H__
+#define __HARDWARE_INI_H__
+
+/*
+ * Timers:
+ * SysTick - system time
+ */
+
+
+void GPIO_init();
+void SysTick_init();
+
+/*
+ * Buttons on devboard
+ */
+#define BTNS_PORT		GPIOC
+// PCO -- S2
+#define BTN_S2_PIN		GPIO0
+// PC1 -- S3
+#define BTN_S3_PIN		GPIO1
+
+/*
+ * LEDS: PB9 for D1, PB8 for D2
+ */
+#define LEDS_PORT		GPIOB
+#define LED_D1_PIN		GPIO9
+#define LED_D2_PIN		GPIO8
+
+/*
+ * USB interface
+ * connect boot1 jumper to gnd, boot0 to gnd; and reconnect boot0 to +3.3 to boot flash
+ */
+/*
+// USB_DICS (disconnect) - PC11
+#define USB_DISC_PIN		GPIO11
+#define USB_DISC_PORT		GPIOC
+// USB_POWER (high level when USB connected to PC)
+#define USB_POWER_PIN		GPIO10
+#define USB_POWER_PORT		GPIOC
+// change signal level on USB diconnect pin
+#define usb_disc_high()   gpio_set(USB_DISC_PORT, USB_DISC_PIN)
+#define usb_disc_low()    gpio_clear(USB_DISC_PORT, USB_DISC_PIN)
+// in case of n-channel FET on 1.5k pull-up change on/off disconnect means low level
+// in case of pnp bipolar transistor or p-channel FET on 1.5k pull-up disconnect means high level
+#define usb_disconnect()  usb_disc_high()
+#define usb_connect()     usb_disc_low()
+*/
+// my simple devboard have no variants for programmed connection/disconnection of USB
+#define usb_disconnect()
+#define usb_connect()
+
+void check_btns();
+
+#endif // __HARDWARE_INI_H__
diff --git a/GPS/ld/devices.data b/GPS/ld/devices.data
new file mode 100644
index 0000000..7f29538
--- /dev/null
+++ b/GPS/ld/devices.data
@@ -0,0 +1,9 @@
+stm32f103?4* stm32f1 ROM=16K RAM=6K
+stm32f103?6* stm32f1 ROM=32K RAM=10K
+stm32f103?8* stm32f1 ROM=64K RAM=20K
+stm32f103?b* stm32f1 ROM=128K RAM=20K
+stm32f103?c* stm32f1 ROM=256K RAM=48K
+stm32f103?d* stm32f1 ROM=384K RAM=64K
+stm32f103?e* stm32f1 ROM=512K RAM=64K
+stm32f103?f* stm32f1 ROM=768K RAM=96K
+stm32f103?g* stm32f1 ROM=1024K RAM=96K
diff --git a/GPS/ld/stm32f103x4.ld b/GPS/ld/stm32f103x4.ld
new file mode 100644
index 0000000..efed65e
--- /dev/null
+++ b/GPS/ld/stm32f103x4.ld
@@ -0,0 +1,31 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2012 Karl Palsson <karlp@tweak.net.au>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Linker script for STM32F100x4, 16K flash, 4K RAM. */
+
+/* Define memory regions. */
+MEMORY
+{
+	rom (rx) : ORIGIN = 0x08000000, LENGTH = 16K
+	ram (rwx) : ORIGIN = 0x20000000, LENGTH = 6K
+}
+
+/* Include the common ld script. */
+INCLUDE libopencm3_stm32f1.ld
+
diff --git a/GPS/ld/stm32f103x6.ld b/GPS/ld/stm32f103x6.ld
new file mode 100644
index 0000000..13f05f9
--- /dev/null
+++ b/GPS/ld/stm32f103x6.ld
@@ -0,0 +1,31 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2012 Karl Palsson <karlp@tweak.net.au>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Linker script for STM32F100x4, 16K flash, 4K RAM. */
+
+/* Define memory regions. */
+MEMORY
+{
+	rom (rx) : ORIGIN = 0x08000000, LENGTH =  32K
+	ram (rwx) : ORIGIN = 0x20000000, LENGTH = 10K
+}
+
+/* Include the common ld script. */
+INCLUDE libopencm3_stm32f1.ld
+
diff --git a/GPS/ld/stm32f103x8.ld b/GPS/ld/stm32f103x8.ld
new file mode 100644
index 0000000..2c4640f
--- /dev/null
+++ b/GPS/ld/stm32f103x8.ld
@@ -0,0 +1,31 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2012 Karl Palsson <karlp@tweak.net.au>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Linker script for STM32F100x4, 16K flash, 4K RAM. */
+
+/* Define memory regions. */
+MEMORY
+{
+	rom (rx) : ORIGIN = 0x08000000, LENGTH =  64K
+	ram (rwx) : ORIGIN = 0x20000000, LENGTH = 20K
+}
+
+/* Include the common ld script. */
+INCLUDE libopencm3_stm32f1.ld
+
diff --git a/GPS/ld/stm32f103xB.ld b/GPS/ld/stm32f103xB.ld
new file mode 100644
index 0000000..138444d
--- /dev/null
+++ b/GPS/ld/stm32f103xB.ld
@@ -0,0 +1,31 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2012 Karl Palsson <karlp@tweak.net.au>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Linker script for STM32F100x4, 16K flash, 4K RAM. */
+
+/* Define memory regions. */
+MEMORY
+{
+	rom (rx) : ORIGIN = 0x08000000, LENGTH = 128K
+	ram (rwx) : ORIGIN = 0x20000000, LENGTH = 20K
+}
+
+/* Include the common ld script. */
+INCLUDE libopencm3_stm32f1.ld
+
diff --git a/GPS/ld/stm32f103xC.ld b/GPS/ld/stm32f103xC.ld
new file mode 100644
index 0000000..fda76bf
--- /dev/null
+++ b/GPS/ld/stm32f103xC.ld
@@ -0,0 +1,31 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2012 Karl Palsson <karlp@tweak.net.au>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Linker script for STM32F100x4, 16K flash, 4K RAM. */
+
+/* Define memory regions. */
+MEMORY
+{
+	rom (rx) : ORIGIN = 0x08000000, LENGTH = 256K
+	ram (rwx) : ORIGIN = 0x20000000, LENGTH = 48K
+}
+
+/* Include the common ld script. */
+INCLUDE libopencm3_stm32f1.ld
+
diff --git a/GPS/ld/stm32f103xD.ld b/GPS/ld/stm32f103xD.ld
new file mode 100644
index 0000000..0f996c2
--- /dev/null
+++ b/GPS/ld/stm32f103xD.ld
@@ -0,0 +1,31 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2012 Karl Palsson <karlp@tweak.net.au>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Linker script for STM32F100x4, 16K flash, 4K RAM. */
+
+/* Define memory regions. */
+MEMORY
+{
+	rom (rx) : ORIGIN = 0x08000000, LENGTH = 384K
+	ram (rwx) : ORIGIN = 0x20000000, LENGTH = 64K
+}
+
+/* Include the common ld script. */
+INCLUDE libopencm3_stm32f1.ld
+
diff --git a/GPS/ld/stm32f103xE.ld b/GPS/ld/stm32f103xE.ld
new file mode 100644
index 0000000..b0fcb69
--- /dev/null
+++ b/GPS/ld/stm32f103xE.ld
@@ -0,0 +1,31 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2012 Karl Palsson <karlp@tweak.net.au>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Linker script for STM32F100x4, 16K flash, 4K RAM. */
+
+/* Define memory regions. */
+MEMORY
+{
+	rom (rx) : ORIGIN = 0x08000000, LENGTH = 512K
+	ram (rwx) : ORIGIN = 0x20000000, LENGTH = 64K
+}
+
+/* Include the common ld script. */
+INCLUDE libopencm3_stm32f1.ld
+
diff --git a/GPS/ld/stm32f103xF.ld b/GPS/ld/stm32f103xF.ld
new file mode 100644
index 0000000..62d47db
--- /dev/null
+++ b/GPS/ld/stm32f103xF.ld
@@ -0,0 +1,31 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2012 Karl Palsson <karlp@tweak.net.au>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Linker script for STM32F100x4, 16K flash, 4K RAM. */
+
+/* Define memory regions. */
+MEMORY
+{
+	rom (rx) : ORIGIN = 0x08000000, LENGTH = 768K
+	ram (rwx) : ORIGIN = 0x20000000, LENGTH = 96K
+}
+
+/* Include the common ld script. */
+INCLUDE libopencm3_stm32f1.ld
+
diff --git a/GPS/ld/stm32f103xG.ld b/GPS/ld/stm32f103xG.ld
new file mode 100644
index 0000000..0c0c968
--- /dev/null
+++ b/GPS/ld/stm32f103xG.ld
@@ -0,0 +1,31 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2012 Karl Palsson <karlp@tweak.net.au>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Linker script for STM32F100x4, 16K flash, 4K RAM. */
+
+/* Define memory regions. */
+MEMORY
+{
+	rom (rx) : ORIGIN = 0x08000000, LENGTH = 1024K
+	ram (rwx) : ORIGIN = 0x20000000, LENGTH =  96K
+}
+
+/* Include the common ld script. */
+INCLUDE libopencm3_stm32f1.ld
+
diff --git a/GPS/main.c b/GPS/main.c
new file mode 100644
index 0000000..c1c2804
--- /dev/null
+++ b/GPS/main.c
@@ -0,0 +1,98 @@
+/*
+ * main.c
+ *
+ * Copyright 2014 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#include "main.h"
+#include "hardware_ini.h"
+#include "cdcacm.h"
+#include "uart.h"
+#include "GPS.h"
+
+volatile uint32_t Ticks = 0; // global ticks (10kHz)
+volatile uint32_t Timer = 0; // global timer (milliseconds)
+usbd_device *usbd_dev;
+
+int main(){
+	uint32_t usb_timer = 0;
+	uint8_t *string;
+	// RCC clocking: 8MHz oscillator -> 72MHz system
+	rcc_clock_setup_in_hse_8mhz_out_72mhz();
+
+	GPIO_init();
+
+	usb_disconnect(); // turn off USB while initializing all
+
+	// USB
+	usbd_dev = USB_init();
+
+	// SysTick is a system timer with 1ms period
+	SysTick_init();
+	UART_init(USART2); // init GPS UART
+
+	// wait a little and then turn on USB pullup
+//	for (i = 0; i < 0x800000; i++)
+//		__asm__("nop");
+
+	usb_connect(); // turn on USB
+
+	GPS_send_start_seq();
+
+	while(1){
+		usbd_poll(usbd_dev);
+		if(usbdatalen){ // there's something in USB buffer
+			usbdatalen = parce_incoming_buf(usbdatabuf, usbdatalen);
+		}
+		if((string = check_UART2()))
+			GPS_parse_answer(string);
+		if(Ticks - usb_timer > 9){ // 1ms cycle
+			usb_timer += 10;
+			//usb_send_buffer();
+		}else if(Ticks < usb_timer){ // Timer overflow
+			usb_timer = 0;
+		}
+	}
+}
+
+
+/**
+ * SysTick interrupt: increment global time & send data buffer through USB
+ */
+void sys_tick_handler(){
+	static int T = 0; // 0..10 - for millisecond timer
+	++Ticks;
+	if(++T == 10){
+		usb_send_buffer();
+		++Timer;
+		T = 0;
+	}
+}
+
+// pause function, delay in ms
+void Delay(uint16_t _U_ time){
+	uint32_t waitto = Timer + time;
+	while(Timer < waitto);
+}
+
+/**
+ * print current time in milliseconds
+ */
+void print_time(){
+	print_int(Timer);
+}
diff --git a/GPS/main.h b/GPS/main.h
new file mode 100644
index 0000000..54c68ba
--- /dev/null
+++ b/GPS/main.h
@@ -0,0 +1,55 @@
+/*
+ * main.h
+ *
+ * Copyright 2014 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+
+#pragma once
+#ifndef __MAIN_H__
+#define __MAIN_H__
+
+#include <stdlib.h>
+#include <libopencm3/stm32/gpio.h>
+#include <libopencm3/stm32/usart.h>
+#include <libopencm3/cm3/nvic.h>
+#include <libopencm3/usb/cdc.h>
+#include <libopencm3/usb/usbd.h>
+#include <libopencm3/cm3/systick.h>
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/adc.h>
+#include <libopencm3/stm32/dma.h>
+#include <libopencm3/stm32/spi.h>
+
+#define ADC_CHANNELS_NUMBER    (10)
+
+#include "sync.h" // mutexes
+#include "user_proto.h"
+
+extern void *memcpy(void *dest, const void *src, int n);
+
+#define _U_    __attribute__((__unused__))
+#define  U8(x)  ((uint8_t)  x)
+#define U16(x)  ((uint16_t) x)
+#define U32(x)  ((uint32_t) x)
+
+extern volatile uint32_t Timer; // global timer (milliseconds)
+void Delay(uint16_t time);
+
+#endif // __MAIN_H__
+
diff --git a/GPS/sync.c b/GPS/sync.c
new file mode 100644
index 0000000..ba688c3
--- /dev/null
+++ b/GPS/sync.c
@@ -0,0 +1,93 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2012 Fergus Noble <fergusnoble@gmail.com>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * TODO:
+ *   implement mutexes for other type of MCU (which doesn't have strex & ldrex)
+ */
+
+#include <libopencm3/cm3/sync.h>
+
+/* DMB is supported on CM0 */
+void __dmb()
+{
+	__asm__ volatile ("dmb");
+}
+
+/* Those are defined only on CM3 or CM4 */
+#if defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7EM__)
+
+uint32_t __ldrex(volatile uint32_t *addr)
+{
+	uint32_t res;
+	__asm__ volatile ("ldrex %0, [%1]" : "=r" (res) : "r" (addr));
+	return res;
+}
+
+uint32_t __strex(uint32_t val, volatile uint32_t *addr)
+{
+	uint32_t res;
+	__asm__ volatile ("strex %0, %2, [%1]"
+			  : "=&r" (res) : "r" (addr), "r" (val));
+	return res;
+}
+
+void mutex_lock(mutex_t *m)
+{
+	uint32_t status = 0;
+
+	do {
+		/* Wait until the mutex is unlocked. */
+		while (__ldrex(m) != MUTEX_UNLOCKED);
+
+		/* Try to acquire it. */
+		status = __strex(MUTEX_LOCKED, m);
+
+	/* Did we get it? If not then try again. */
+	} while (status != 0);
+
+	/* Execute the mysterious Data Memory Barrier instruction! */
+	__dmb();
+}
+
+void mutex_unlock(mutex_t *m)
+{
+	/* Ensure accesses to protected resource are finished */
+	__dmb();
+
+	/* Free the lock. */
+	*m = MUTEX_UNLOCKED;
+}
+
+/*
+ * Try to lock mutex
+ * if it's already locked or there was error in STREX, return MUTEX_LOCKED
+ * else return MUTEX_UNLOCKED
+ */
+mutex_t mutex_trylock(mutex_t *m){
+	uint32_t status = 0;
+	mutex_t old_lock = __ldrex(m); // get mutex value
+	// set mutex
+	status = __strex(MUTEX_LOCKED, m);
+	if(status == 0) __dmb();
+	else old_lock = MUTEX_LOCKED;
+	return old_lock;
+}
+
+#endif
diff --git a/GPS/sync.h b/GPS/sync.h
new file mode 100644
index 0000000..bfe837b
--- /dev/null
+++ b/GPS/sync.h
@@ -0,0 +1,53 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2012 Fergus Noble <fergusnoble@gmail.com>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef LIBOPENCM3_CM3_SYNC_H
+#define LIBOPENCM3_CM3_SYNC_H
+
+void __dmb(void);
+
+/* Implements synchronisation primitives as discussed in the ARM document
+ * DHT0008A (ID081709) "ARM Synchronization Primitives" and the ARM v7-M
+ * Architecture Reference Manual.
+*/
+
+/* --- Exclusive load and store instructions ------------------------------- */
+
+/* Those are defined only on CM3 or CM4 */
+#if defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7EM__)
+
+uint32_t __ldrex(volatile uint32_t *addr);
+uint32_t __strex(uint32_t val, volatile uint32_t *addr);
+
+/* --- Convenience functions ----------------------------------------------- */
+
+/* Here we implement some simple synchronisation primitives. */
+
+typedef uint32_t mutex_t;
+
+#define MUTEX_UNLOCKED 0
+#define MUTEX_LOCKED   1
+
+void mutex_lock(mutex_t *m);
+void mutex_unlock(mutex_t *m);
+mutex_t mutex_trylock(mutex_t *m);
+
+#endif
+
+#endif
diff --git a/GPS/uart.c b/GPS/uart.c
new file mode 100644
index 0000000..7e83fbe
--- /dev/null
+++ b/GPS/uart.c
@@ -0,0 +1,265 @@
+/*
+ * uart.c - functions to work with UART
+ *
+ * Copyright 2014 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#include "main.h"
+#include "uart.h"
+#include "cdcacm.h"
+#include "hardware_ini.h"
+#include <string.h> // for memcpy
+
+// Buffers for Tx
+static UART_buff TX_buffer[2]; // Tx buffers for all three ports
+static UART_buff RX_buffer[2]; // Rx buffers for all three ports
+
+void fill_uart_RXbuff(uint32_t UART, uint8_t byte);
+
+/**
+ * Set UART speed
+ * @param lc - UART parameters or NULL for value from cdcacm.c (started - B115200,8,N,1)
+ */
+void UART_setspeed(uint32_t UART){
+	usart_set_baudrate(UART, 9600);
+	usart_set_databits(UART, 8);
+	usart_set_stopbits(UART, USART_STOPBITS_1);
+	usart_set_parity(UART, USART_PARITY_NONE);
+	usart_set_flow_control(UART, USART_FLOWCONTROL_NONE);
+	usart_set_mode(UART, USART_MODE_TX_RX);
+}
+
+/**
+ * Setup UART
+ */
+void UART_init(uint32_t UART){
+	uint32_t irq, rcc, rccgpio, gpioport, gpiopin;
+	switch(UART){
+		case USART2: // GPS UART
+			irq = NVIC_USART2_IRQ; // interrupt for given USART
+			rcc = RCC_USART2;      // RCC timing of USART
+			rccgpio = RCC_GPIOA;   // RCC timing of GPIO pin (for output)
+			TX_buffer[1].end = 0;  // reset counters
+			TX_buffer[1].start = 0;
+			RX_buffer[1].end = 0;
+			RX_buffer[1].start = 0;
+			// output pin setup
+			gpioport = GPIO_BANK_USART2_TX;
+			gpiopin  = GPIO_USART2_TX;
+		break;
+		case USART1:
+		default:
+			irq = NVIC_USART1_IRQ;
+			rcc = RCC_USART1;
+			rccgpio = RCC_GPIOA;
+			TX_buffer[0].end = 0;
+			TX_buffer[0].start = 0;
+			RX_buffer[0].end = 0;
+			RX_buffer[0].start = 0;
+			gpioport = GPIO_BANK_USART1_TX;
+			gpiopin  = GPIO_USART1_TX;
+	}
+	// enable clocking
+	rcc_periph_clock_enable(RCC_AFIO); // alternate functions
+	rcc_periph_clock_enable(rcc);      // USART
+	rcc_periph_clock_enable(rccgpio);  // GPIO pins
+	// enable output pin
+	gpio_set_mode(gpioport, GPIO_MODE_OUTPUT_50_MHZ,
+				GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, gpiopin);
+	// enable IRQ
+	nvic_enable_irq(irq);
+	UART_setspeed(UART);
+	// Enable UART receive interrupt
+	USART_CR1(UART) |= USART_CR1_RXNEIE;
+	// Enable UART
+	usart_enable(UART);
+}
+
+/*
+ * UART interrupts
+ */
+// common
+void UART_isr(uint32_t UART){
+	uint8_t bufidx = 0, data;
+	UART_buff *curbuff;
+	// Check if we were called because of RXNE
+	if(USART_SR(UART) & USART_SR_RXNE){
+		// parce incoming byte
+		data = usart_recv(UART);
+		fill_uart_RXbuff(UART, data);
+	}
+	// Check if we were called because of TXE -> send next byte in buffer
+	if((USART_CR1(UART) & USART_CR1_TXEIE) && (USART_SR(UART) & USART_SR_TXE)){
+		switch(UART){
+			case USART1:
+				bufidx = 0;
+			break;
+			case USART2:
+				bufidx = 1;
+			break;
+			default: // error - return
+				return;
+		}
+		curbuff = &TX_buffer[bufidx];
+		bufidx = curbuff->start; // start of data in buffer
+		if(bufidx != curbuff->end){ // there's data in buffer
+			// Put data into the transmit register
+			usart_send(UART, curbuff->buf[bufidx]);
+			if(++(curbuff->start) == UART_BUF_DATA_SIZE){ // reload start
+				curbuff->start = 0;
+			}
+		}else{ // Disable the TXE interrupt, it's no longer needed
+			USART_CR1(UART) &= ~USART_CR1_TXEIE;
+			// empty indexes
+			curbuff->start = 0;
+			curbuff->end = 0;
+		}
+	}
+}
+// particular interrupt handlers
+void usart1_isr(){
+	UART_isr(USART1);
+}
+void usart2_isr(){
+	UART_isr(USART2);
+}
+
+// put byte into Tx buffer
+void fill_uart_buff(uint32_t UART, uint8_t byte){
+	UART_buff *curbuff;
+	uint8_t bufidx = 0, endidx;
+	if(!(USART_CR1(UART) & USART_CR1_UE)) return; // UART disabled
+	USART_CR1(UART) &= ~USART_CR1_TXEIE; // disable TX interrupt while buffer filling
+	while ((USART_SR(UART) & USART_SR_TXE) == 0); // wait until last byte send
+	switch(UART){
+		case USART1:
+			bufidx = 0;
+		break;
+		case USART2:
+			bufidx = 1;
+		break;
+		case USART3:
+			bufidx = 2;
+		break;
+		default: // error - return
+			return;
+	}
+	curbuff = &TX_buffer[bufidx];
+	bufidx = curbuff->start; // start of data in buffer
+	endidx = curbuff->end; // end of data
+	curbuff->buf[endidx++] = byte; // put byte into buffer
+	// now check indexes
+	if(endidx != bufidx && endidx != UART_BUF_DATA_SIZE){ // all OK - there's enough place for data
+		(curbuff->end)++; // just increment index in buffer
+	}else{ // dangerous situation: possible overflow
+		if(endidx == UART_BUF_DATA_SIZE){ // end of buffer
+			if(bufidx != 0){ // no overflow
+				curbuff->end = 0;
+				goto end_of_fn;
+			}
+		}
+		// overflow: purge all data
+		bufidx = curbuff->start; // refresh data index
+		for(endidx = bufidx; endidx < UART_BUF_DATA_SIZE; endidx++) // first data porion
+			usart_send(UART, curbuff->buf[endidx]);
+		for(endidx = 0; endidx < bufidx; endidx++) // rest of data
+			usart_send(UART, curbuff->buf[endidx]);
+		curbuff->start = 0;
+		curbuff->end = 0;
+		return;
+	}
+	end_of_fn:
+	// enable interrupts to send data from buffer
+	USART_CR1(UART) |= USART_CR1_TXEIE;
+}
+
+/**
+ * send data over UART - one function for each uart
+ * @param byte - one byte to put in UART queue
+ */
+void uart1_send(uint8_t byte){
+	fill_uart_buff(USART1, byte);
+}
+void uart2_send(uint8_t byte){
+	fill_uart_buff(USART2, byte);
+}
+/*
+UART_buff *get_uart_buffer(uint32_t UART){
+	switch(UART){
+		case USART1:
+			return &RX_buffer[0];
+		break;
+		case USART2:
+			return &RX_buffer[1];
+		break;
+		default: // error - return
+			return NULL;
+	}
+	return NULL;
+}*/
+
+
+/**
+ * Check whether UART2 have a full text line
+ * @return string with data if data ready or NULL
+ */
+uint8_t *check_UART2(){
+	static int oldlen = 0;
+	static uint8_t buf[UART_BUF_DATA_SIZE+1];
+	UART_buff *curbuff = &RX_buffer[1];
+	uint8_t datalen = curbuff->end; // length of data in buffer - here we use param "end"
+	if(!datalen) return NULL; // buffer is empty
+	if(oldlen != datalen){
+		if(curbuff->buf[curbuff->end-1] != '\n'){ // string not full
+			oldlen = datalen;
+			return NULL;
+		}else{ // full string - copy it to buffer & clear indexes
+			memcpy(buf, curbuff->buf, datalen);
+			buf[datalen] = 0;
+			oldlen = curbuff->end = 0;
+			return buf;
+		}
+	}
+	return NULL;
+}
+
+/**
+ * Fill data in RX buffer to prepare it for further work
+ * we don't use "start" parameter here, it's 0 always
+ * @param UART - device to fill buffer
+ * @param byte - data byte
+ */
+void fill_uart_RXbuff(uint32_t UART, uint8_t byte){
+	UART_buff *curbuff;
+	uint8_t bufidx;
+	switch(UART){
+		case USART1:
+			bufidx = 0;
+		break;
+		case USART2:
+			bufidx = 1;
+		break;
+		default: // error - return
+			return;
+	}
+	curbuff = &RX_buffer[bufidx];
+	if(curbuff->end == UART_BUF_DATA_SIZE){ // end of buffer - forget about data
+		return;
+	}
+	curbuff->buf[curbuff->end++] = byte; // put byte into buffer
+}
diff --git a/GPS/uart.h b/GPS/uart.h
new file mode 100644
index 0000000..85715ca
--- /dev/null
+++ b/GPS/uart.h
@@ -0,0 +1,46 @@
+/*
+ * uart.h
+ *
+ * Copyright 2014 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#pragma once
+#ifndef __UART_H__
+#define __UART_H__
+
+// Size of buffers
+#define UART_BUF_DATA_SIZE            128
+
+typedef struct {
+	uint8_t buf[UART_BUF_DATA_SIZE];
+	uint8_t start; // index from where to start reading
+	uint8_t end;   // index from where to start writing
+} UART_buff;
+
+void UART_init(uint32_t UART);
+void UART_setspeed(uint32_t UART);
+
+void fill_uart_buff(uint32_t UART, uint8_t byte);
+void uart1_send(uint8_t byte);
+void uart2_send(uint8_t byte);
+
+uint8_t *check_UART2();
+
+UART_buff *get_uart_buffer(uint32_t UART);
+
+#endif // __UART_H__
diff --git a/GPS/user_proto.c b/GPS/user_proto.c
new file mode 100644
index 0000000..aa904ba
--- /dev/null
+++ b/GPS/user_proto.c
@@ -0,0 +1,198 @@
+/*
+ * user_proto.c
+ *
+ * Copyright 2014 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#include "cdcacm.h"
+#include "main.h"
+#include "hardware_ini.h"
+#include "GPS.h"
+
+// integer value given by user
+static volatile int32_t User_value = 0;
+enum{
+	UVAL_START,		// user start to write integer value
+	UVAL_ENTERED,	// value entered but not printed
+	UVAL_BAD		// entered bad value
+};
+uint8_t Uval_ready = UVAL_BAD;
+
+int read_int(char *buf, int cnt);
+
+intfun I = NULL; // function to process entered integer
+
+#define READINT() do{i += read_int(&buf[i+1], len-i-1);}while(0)
+
+void help(){
+	P("H\tshow this help\n");
+//	P("I\ttest entering integer value\n");
+	P("T\tshow current approx. time\n");
+}
+
+/**
+ * show entered integer value
+ */
+uint8_t show_int(int32_t v){
+	newline();
+	print_int(v);
+	newline();
+	return 0;
+}
+
+/**
+ * parce command buffer buf with length len
+ * return 0 if buffer processed or len if there's not enough data in buffer
+ */
+int parce_incoming_buf(char *buf, int len){
+	uint8_t command;
+	//uint32_t utmp;
+	int i = 0;
+	if(Uval_ready == UVAL_START){ // we are in process of user's value reading
+		i += read_int(buf, len);
+	}
+	if(Uval_ready == UVAL_ENTERED){
+		//print_int(User_value); // printout readed integer value for error control
+		Uval_ready = UVAL_BAD; // clear Uval
+		I(User_value);
+		return 0;
+	}
+	for(; i < len; i++){
+		command = buf[i];
+		if(!command) continue; // omit zero
+		switch (command){
+			case 'H': // show help
+				help();
+			break;
+/*			case 'I': // enter integer & show its value
+				I = show_int;
+				READINT();
+			break;*/
+			case 'T':
+				newline();
+				print_int(Timer); // be careful for Time >= 2^{31}!!!
+				newline();
+			break;
+			case '\n': // show newline, space and tab as is
+			case '\r':
+			case ' ':
+			case '\t':
+			break;
+			default:
+				command = '?'; // echo '?' on unknown command in byte mode
+		}
+		usb_send(command); // echo readed byte
+	}
+	return 0; // all data processed - 0 bytes leave in buffer
+}
+
+/**
+ * Send char array wrd thru USB or UART
+ */
+void prnt(uint8_t *wrd){
+	if(!wrd) return;
+	while(*wrd) usb_send(*wrd++);
+}
+
+/**
+ * Read from TTY integer value given by user (in DEC).
+ *    Reading stops on first non-numeric symbol.
+ *    To work with symbol terminals reading don't stops on buffer's end,
+ *    it waits for first non-numeric char.
+ *    When working on string terminals, terminate string by '\n', 0 or any other symbol
+ * @param buf - buffer to read from
+ * @param cnt - buffer length
+ * @return amount of readed symbols
+ */
+int read_int(char *buf, int cnt){
+	int readed = 0, i;
+	static int enteredDigits; // amount of entered digits
+	static int sign; // sign of readed value
+	if(Uval_ready){ // this is first run
+		Uval_ready = UVAL_START; // clear flag
+		enteredDigits = 0; // 0 digits entered
+		User_value = 0; // clear value
+		sign = 1; // clear sign
+	}
+	if(!cnt) return 0;
+	for(i = 0; i < cnt; i++, readed++){
+		uint8_t chr = buf[i];
+		if(chr == '-'){
+			if(enteredDigits == 0){ // sign should be first
+				sign = -1;
+				continue;
+			}else{ // '-' after number - reject entered value
+				Uval_ready = UVAL_BAD;
+				break;
+			}
+		}
+		if(chr < '0' || chr > '9'){
+			if(enteredDigits)
+				Uval_ready = UVAL_ENTERED;
+			else
+				Uval_ready = UVAL_BAD; // bad symbol
+			break;
+		}
+		User_value = User_value * 10 + (int32_t)(chr - '0');
+		enteredDigits++;
+	}
+	if(Uval_ready == UVAL_ENTERED) // reading has met an non-numeric character
+		User_value *= sign;
+	return readed;
+}
+
+/**
+ * Print buff as hex values
+ * @param buf - buffer to print
+ * @param l   - buf length
+ * @param s   - function to send a byte
+ */
+void print_hex(uint8_t *buff, uint8_t l){
+	void putc(uint8_t c){
+		if(c < 10)
+			usb_send(c + '0');
+		else
+			usb_send(c + 'a' - 10);
+	}
+	usb_send('0'); usb_send('x'); // prefix 0x
+	while(l--){
+		putc(buff[l] >> 4);
+		putc(buff[l] & 0x0f);
+	}
+}
+
+/**
+ * Print decimal integer value
+ * @param N - value to print
+ * @param s - function to send a byte
+ */
+void print_int(int32_t N){
+	uint8_t buf[10], L = 0;
+	if(N < 0){
+		usb_send('-');
+		N = -N;
+	}
+	if(N){
+		while(N){
+			buf[L++] = N % 10 + '0';
+			N /= 10;
+		}
+		while(L--) usb_send(buf[L]);
+	}else usb_send('0');
+}
+
diff --git a/GPS/user_proto.h b/GPS/user_proto.h
new file mode 100644
index 0000000..4b0fc3a
--- /dev/null
+++ b/GPS/user_proto.h
@@ -0,0 +1,47 @@
+/*
+ * user_proto.h
+ *
+ * Copyright 2014 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#pragma once
+#ifndef __USER_PROTO_H__
+#define __USER_PROTO_H__
+
+#include "cdcacm.h"
+
+// shorthand for prnt
+#define P(arg)   do{prnt((uint8_t*)arg);}while(0)
+// debug message - over USB
+#ifdef EBUG
+	#define DBG(a)    do{prnt((uint8_t*)a);}while(0)
+#else
+	#define DBG(a)
+#endif
+
+typedef uint8_t (*intfun)(int32_t);
+
+void prnt(uint8_t *wrd);
+#define newline()   usb_send('\n')
+
+void print_int(int32_t N);
+void print_hex(uint8_t *buff, uint8_t l);
+
+int parce_incoming_buf(char *buf, int len);
+
+#endif // __USER_PROTO_H__