diff --git a/F1:F103/FX3U/Makefile b/F1:F103/FX3U/Makefile
new file mode 100644
index 0000000..865c9a7
--- /dev/null
+++ b/F1:F103/FX3U/Makefile
@@ -0,0 +1,10 @@
+BINARY      := fx3u
+# MCU code
+MCU         ?= F103xC
+# change this linking script depending on particular MCU model,
+LDSCRIPT    ?= stm32f103xC.ld
+DEFINES     := -DSTM32F10X_HD
+INC_DIR     := ../inc
+
+include ../makefile.f1
+include ../../makefile.stm32
diff --git a/F1:F103/FX3U/adc.c b/F1:F103/FX3U/adc.c
new file mode 100644
index 0000000..ee10071
--- /dev/null
+++ b/F1:F103/FX3U/adc.c
@@ -0,0 +1,110 @@
+/*
+ * This file is part of the fx3u project.
+ * Copyright 2024 Edward V. Emelianov <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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "adc.h"
+
+uint16_t ADC_array[NUMBER_OF_ADC_CHANNELS*9];
+
+void adc_setup(){
+    uint32_t ctr = 0;
+    // Enable clocking
+    RCC->APB2ENR |= RCC_APB2ENR_ADC1EN;
+    RCC->AHBENR |= RCC_AHBENR_DMA1EN;
+    __DSB();
+    // DMA configuration
+    DMA1_Channel1->CPAR = (uint32_t) (&(ADC1->DR));
+    DMA1_Channel1->CMAR = (uint32_t)(ADC_array);
+    DMA1_Channel1->CNDTR = NUMBER_OF_ADC_CHANNELS * 9;
+    DMA1_Channel1->CCR = DMA_CCR_MINC | DMA_CCR_MSIZE_0 | DMA_CCR_PSIZE_0
+                          | DMA_CCR_CIRC | DMA_CCR_PL | DMA_CCR_EN;
+    RCC->CFGR = (RCC->CFGR & ~(RCC_CFGR_ADCPRE)) | RCC_CFGR_ADCPRE_DIV8; // ADC clock = RCC / 8
+    // sampling time - 239.5 cycles for channels 0, 16 and 17
+    ADC1->SMPR2 = ADC_SMPR2_SMP0;
+    ADC1->SMPR1 = ADC_SMPR1_SMP16 | ADC_SMPR1_SMP17;
+    // sequence order: 0 -> 16 -> 17
+    ADC1->SQR3 = (0 << 0) | (16<<5) | (17 << 10);
+    ADC1->SQR1 = (NUMBER_OF_ADC_CHANNELS - 1) << 20; // amount of conversions
+    ADC1->CR1 = ADC_CR1_SCAN; // scan mode
+    // DMA, continuous mode; enable vref & Tsens; enable SWSTART as trigger
+    ADC1->CR2 = ADC_CR2_DMA | ADC_CR2_TSVREFE | ADC_CR2_CONT | ADC_CR2_EXTSEL | ADC_CR2_EXTTRIG;
+    // wake up ADC
+    ADC1->CR2 |= ADC_CR2_ADON;
+    __DSB();
+    // wait for Tstab - at least 1us
+    while(++ctr < 0xff) nop();
+    // calibration
+    ADC1->CR2 |= ADC_CR2_RSTCAL;
+    ctr = 0; while((ADC1->CR2 & ADC_CR2_RSTCAL) && ++ctr < 0xfffff);
+    ADC1->CR2 |= ADC_CR2_CAL;
+    ctr = 0; while((ADC1->CR2 & ADC_CR2_CAL) && ++ctr < 0xfffff);
+    // clear possible errors and start
+    ADC1->SR = 0;
+    ADC1->CR2 |= ADC_CR2_SWSTART;
+}
+
+
+/**
+ * @brief getADCval - calculate median value for `nch` channel
+ * @param nch - number of channel
+ * @return
+ */
+uint16_t getADCval(int nch){
+    int i, addr = nch;
+#define PIX_SORT(a,b) { if ((a)>(b)) PIX_SWAP((a),(b)); }
+#define PIX_SWAP(a,b) { register uint16_t temp=(a);(a)=(b);(b)=temp; }
+    uint16_t p[9];
+    for(i = 0; i < 9; ++i, addr += NUMBER_OF_ADC_CHANNELS){ // first we should prepare array for optmed
+        p[i] = ADC_array[addr];
+    }
+    PIX_SORT(p[1], p[2]) ; PIX_SORT(p[4], p[5]) ; PIX_SORT(p[7], p[8]) ;
+    PIX_SORT(p[0], p[1]) ; PIX_SORT(p[3], p[4]) ; PIX_SORT(p[6], p[7]) ;
+    PIX_SORT(p[1], p[2]) ; PIX_SORT(p[4], p[5]) ; PIX_SORT(p[7], p[8]) ;
+    PIX_SORT(p[0], p[3]) ; PIX_SORT(p[5], p[8]) ; PIX_SORT(p[4], p[7]) ;
+    PIX_SORT(p[3], p[6]) ; PIX_SORT(p[1], p[4]) ; PIX_SORT(p[2], p[5]) ;
+    PIX_SORT(p[4], p[7]) ; PIX_SORT(p[4], p[2]) ; PIX_SORT(p[6], p[4]) ;
+    PIX_SORT(p[4], p[2]) ;
+    return p[4];
+#undef PIX_SORT
+#undef PIX_SWAP
+}
+
+// get voltage @input nch (1/100V)
+uint32_t getADCvoltage(int nch){
+    uint32_t v = getADCval(nch);
+    v *= getVdd();
+    v /= 0xfff; // 12bit ADC
+    return v;
+}
+
+// return MCU temperature (degrees of celsius * 10)
+int32_t getMCUtemp(){
+    // Temp = (V25 - Vsense)/Avg_Slope + 25
+    // V_25 = 1.45V,  Slope = 4.3e-3
+    int32_t Vsense = getVdd() * getADCval(CHTSENS);
+    int32_t temperature = 593920 - Vsense; // 593920 == 145*4096
+    temperature /= 172; // == /(4096*10*4.3e-3), 10 - to convert from *100 to *10
+    temperature += 250;
+    return(temperature);
+}
+
+// return Vdd * 100 (V)
+uint32_t getVdd(){
+    uint32_t vdd = 120 * 4096; // 1.2V
+    vdd /= getADCval(CHVDD);
+    return vdd;
+}
diff --git a/F1:F103/FX3U/adc.h b/F1:F103/FX3U/adc.h
new file mode 100644
index 0000000..b3539cd
--- /dev/null
+++ b/F1:F103/FX3U/adc.h
@@ -0,0 +1,44 @@
+/*
+ * This file is part of the fx3u project.
+ * Copyright 2024 Edward V. Emelianov <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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <stm32f1.h>
+
+#define NUMBER_OF_ADC_CHANNELS (3)
+
+// Vsen voltage channel
+#define CHVSEN  (0)
+// channels for Tsens and Vdd
+#define CHTSENS (1)
+#define CHVDD   (2)
+
+/**
+ * @brief ADC_array - array for ADC channels with median filtering:
+ * 0 - Isensor voltage
+ * 1 - internal Tsens
+ * 2 - Vdd
+ */
+extern uint16_t ADC_array[];
+
+void adc_setup();
+int32_t getMCUtemp();
+uint32_t getVdd();
+uint16_t getADCval(int nch);
+uint32_t getADCvoltage(int nch);
+
diff --git a/F1:F103/FX3U/can.c b/F1:F103/FX3U/can.c
new file mode 100644
index 0000000..ff837d4
--- /dev/null
+++ b/F1:F103/FX3U/can.c
@@ -0,0 +1,296 @@
+/*
+ * This file is part of the fx3u project.
+ * Copyright 2024 Edward V. Emelianov <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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "can.h"
+#include "hardware.h"
+#include "proto.h"
+#include "usart.h"
+
+// REMAPPED to PD0/PD1!!!
+
+#include <string.h> // memcpy
+
+// circular buffer for  received messages
+static CAN_message messages[CAN_INMESSAGE_SIZE];
+static uint8_t first_free_idx = 0;    // index of first empty cell
+static int8_t first_nonfree_idx = -1; // index of first data cell
+static uint16_t oldspeed = 100; // speed of last init
+
+static CAN_status can_status = CAN_STOP;
+
+static void can_process_fifo(uint8_t fifo_num);
+
+CAN_status CAN_get_status(){
+    int st = can_status;
+    can_status = CAN_OK;
+    return st;
+}
+
+// push next message into buffer; return 1 if buffer overfull
+static int CAN_messagebuf_push(CAN_message *msg){
+    //MSG("Try to push\n");
+#ifdef EBUG
+        usart_send("push\n");
+#endif
+    if(first_free_idx == first_nonfree_idx){
+#ifdef EBUG
+        usart_send("INBUF OVERFULL\n");
+#endif
+        return 1; // no free space
+    }
+    if(first_nonfree_idx < 0) first_nonfree_idx = 0;  // first message in empty buffer
+    memcpy(&messages[first_free_idx++], msg, sizeof(CAN_message));
+    // need to roll?
+    if(first_free_idx == CAN_INMESSAGE_SIZE) first_free_idx = 0;
+    return 0;
+}
+
+// pop message from buffer
+CAN_message *CAN_messagebuf_pop(){
+    if(first_nonfree_idx < 0) return NULL;
+    CAN_message *msg = &messages[first_nonfree_idx++];
+    if(first_nonfree_idx == CAN_INMESSAGE_SIZE) first_nonfree_idx = 0;
+    if(first_nonfree_idx == first_free_idx){ // buffer is empty - refresh it
+        first_nonfree_idx = -1;
+        first_free_idx = 0;
+    }
+    return msg;
+}
+
+void CAN_reinit(uint16_t speed){
+    CAN1->TSR |= CAN_TSR_ABRQ0 | CAN_TSR_ABRQ1 | CAN_TSR_ABRQ2;
+    RCC->APB1RSTR |= RCC_APB1RSTR_CAN1RST;
+    RCC->APB1RSTR &= ~RCC_APB1RSTR_CAN1RST;
+    CAN_setup(speed);
+}
+
+/*
+Can filtering: FSCx=0 (CAN1->FS1R) -> 16-bit identifiers
+MASK: FBMx=0 (CAN1->FM1R), two filters (n in FR1 and n+1 in FR2)
+    ID:   CAN1->sFilterRegister[x].FRn[0..15]
+    MASK: CAN1->sFilterRegister[x].FRn[16..31]
+    FR bits:  STID[10:0] RTR IDE EXID[17:15]
+LIST: FBMx=1, four filters (n&n+1 in FR1, n+2&n+3 in FR2)
+    IDn:   CAN1->sFilterRegister[x].FRn[0..15]
+    IDn+1: CAN1->sFilterRegister[x].FRn[16..31]
+*/
+
+/*
+Can timing: main freq - APB (PLL=48MHz)
+segment = 1sync + TBS1 + TBS2, sample point is between TBS1 and TBS2,
+so if TBS1=4 and TBS2=3, sum=8, bit sampling freq is 48/8 = 6MHz
+-> to get   100kbps we need prescaler=60
+            250kbps - 24
+            500kbps - 12
+            1MBps   - 6
+*/
+
+// speed - in kbps
+void CAN_setup(uint16_t speed){
+    if(speed == 0) speed = oldspeed;
+    else if(speed < 50) speed = 50;
+    else if(speed > 3000) speed = 3000;
+    oldspeed = speed;
+    uint32_t tmout = 16000000;
+    // Configure GPIO: PD0 - CAN_Rx, PD1 - CAN_Tx
+    AFIO->MAPR |= AFIO_MAPR_CAN_REMAP_REMAP3;
+    GPIOD->CRL = (GPIOD->CRL & ~(CRL(0,0xf)|CRL(1,0xf))) |
+                 CRL(0, CNF_FLINPUT | MODE_INPUT) | CRL(1, CNF_AFPP | MODE_NORMAL);
+    /* Enable the peripheral clock CAN */
+    RCC->APB1ENR |= RCC_APB1ENR_CAN1EN;
+    /* Configure CAN */
+    /* (1) Enter CAN init mode to write the configuration */
+    /* (2) Wait the init mode entering */
+    /* (3) Exit sleep mode */
+    /* (4) Normal mode, set timing to 100kb/s: TBS1 = 4, TBS2 = 3, prescaler = 60 */
+    /* (5) Leave init mode */
+    /* (6) Wait the init mode leaving */
+    /* (7) Enter filter init mode, (16-bit + mask, bank 0 for FIFO 0) */
+    /* (8) Acivate filter 0 for two IDs */
+    /* (9) Identifier list mode */
+    /* (10) Set the Id list */
+    /* (12) Leave filter init */
+    /* (13) Set error interrupts enable (& bus off) */
+    CAN1->MCR |= CAN_MCR_INRQ; /* (1) */
+    while((CAN1->MSR & CAN_MSR_INAK) != CAN_MSR_INAK) /* (2) */
+        if(--tmout == 0) break;
+    CAN1->MCR &=~ CAN_MCR_SLEEP; /* (3) */
+    CAN1->MCR |= CAN_MCR_ABOM; /* allow automatically bus-off */
+
+    CAN1->BTR =  2 << 20 | 3 << 16 | (4500/speed - 1); //| CAN_BTR_SILM | CAN_BTR_LBKM; /* (4) */
+    CAN1->MCR &= ~CAN_MCR_INRQ; /* (5) */
+    tmout = 16000000;
+    while((CAN1->MSR & CAN_MSR_INAK) == CAN_MSR_INAK) /* (6) */
+        if(--tmout == 0) break;
+    // accept ALL
+    CAN1->FMR = CAN_FMR_FINIT; /* (7) */
+    CAN1->FA1R = CAN_FA1R_FACT0 | CAN_FA1R_FACT1; /* (8) */
+    // set to 1 all needed bits of CAN1->FFA1R to switch given filters to FIFO1
+    CAN1->sFilterRegister[0].FR1 = (1<<21)|(1<<5); // all odd IDs
+    CAN1->FFA1R = 2; // filter 1 for FIFO1, filter 0 - for FIFO0
+    CAN1->sFilterRegister[1].FR1 = (1<<21); // all even IDs
+    CAN1->FMR &= ~CAN_FMR_FINIT; /* (12) */
+    CAN1->IER |= CAN_IER_ERRIE | CAN_IER_FOVIE0 | CAN_IER_FOVIE1 | CAN_IER_BOFIE; /* (13) */
+
+    /* Configure IT */
+    NVIC_SetPriority(USB_LP_CAN1_RX0_IRQn, 0); // RX FIFO0 IRQ
+    NVIC_SetPriority(CAN1_RX1_IRQn, 0); // RX FIFO1 IRQ
+    NVIC_SetPriority(CAN1_SCE_IRQn, 0); // RX status changed IRQ
+    NVIC_EnableIRQ(USB_LP_CAN1_RX0_IRQn);
+    NVIC_EnableIRQ(CAN1_RX1_IRQn);
+    NVIC_EnableIRQ(CAN1_SCE_IRQn);
+    CAN1->MSR = 0; // clear SLAKI, WKUI, ERRI
+    can_status = CAN_READY;
+}
+
+void can_proc(){
+    // check for messages in FIFO0 & FIFO1
+    if(CAN1->RF0R & CAN_RF0R_FMP0){
+        can_process_fifo(0);
+    }
+    if(CAN1->RF1R & CAN_RF1R_FMP1){
+        can_process_fifo(1);
+    }
+    IWDG->KR = IWDG_REFRESH;
+    if(CAN1->ESR & (CAN_ESR_BOFF | CAN_ESR_EPVF | CAN_ESR_EWGF)){ // much errors - restart CAN BUS
+        usart_send("\nToo much errors, restarting CAN!\n");
+        // request abort for all mailboxes
+        CAN1->TSR |= CAN_TSR_ABRQ0 | CAN_TSR_ABRQ1 | CAN_TSR_ABRQ2;
+        // reset CAN bus
+        RCC->APB1RSTR |= RCC_APB1RSTR_CAN1RST;
+        RCC->APB1RSTR &= ~RCC_APB1RSTR_CAN1RST;
+        CAN_setup(0);
+    }
+}
+
+CAN_status can_send(uint8_t *msg, uint8_t len, uint16_t target_id){
+    uint8_t mailbox = 0;
+    // check first free mailbox
+    if(CAN1->TSR & (CAN_TSR_TME)){
+        mailbox = (CAN1->TSR & CAN_TSR_CODE) >> 24;
+    }else{ // no free mailboxes
+        return CAN_BUSY;
+    }
+    CAN_TxMailBox_TypeDef *box = &CAN1->sTxMailBox[mailbox];
+    uint32_t lb = 0, hb = 0;
+    switch(len){
+        case 8:
+            hb |= (uint32_t)msg[7] << 24;
+            __attribute__((fallthrough));
+        case 7:
+            hb |= (uint32_t)msg[6] << 16;
+            __attribute__((fallthrough));
+        case 6:
+            hb |= (uint32_t)msg[5] << 8;
+            __attribute__((fallthrough));
+        case 5:
+            hb |= (uint32_t)msg[4];
+            __attribute__((fallthrough));
+        case 4:
+            lb |= (uint32_t)msg[3] << 24;
+            __attribute__((fallthrough));
+        case 3:
+            lb |= (uint32_t)msg[2] << 16;
+            __attribute__((fallthrough));
+        case 2:
+            lb |= (uint32_t)msg[1] << 8;
+            __attribute__((fallthrough));
+        default:
+            lb |= (uint32_t)msg[0];
+    }
+    box->TDLR = lb;
+    box->TDHR = hb;
+    box->TDTR = len;
+    box->TIR  = (target_id & 0x7FF) << 21 | CAN_TI0R_TXRQ;
+    return CAN_OK;
+}
+
+static void can_process_fifo(uint8_t fifo_num){
+    if(fifo_num > 1) return;
+    CAN_FIFOMailBox_TypeDef *box = &CAN1->sFIFOMailBox[fifo_num];
+    volatile uint32_t *RFxR = (fifo_num) ? &CAN1->RF1R : &CAN1->RF0R;
+    // read all
+    while(*RFxR & CAN_RF0R_FMP0){ // amount of messages pending
+        // CAN_RDTxR: (16-31) - timestamp, (8-15) - filter match index, (0-3) - data length
+        /* TODO: check filter match index if more than one ID can receive */
+        CAN_message msg;
+        uint8_t *dat = msg.data;
+        uint8_t len = box->RDTR & 0x0f;
+        msg.length = len;
+        msg.ID = box->RIR >> 21;
+        //msg.filterNo = (box->RDTR >> 8) & 0xff;
+        //msg.fifoNum = fifo_num;
+        if(len){ // message can be without data
+            uint32_t hb = box->RDHR, lb = box->RDLR;
+            switch(len){
+                case 8:
+                    dat[7] = hb>>24;
+                    __attribute__((fallthrough));
+                case 7:
+                    dat[6] = (hb>>16) & 0xff;
+                    __attribute__((fallthrough));
+                case 6:
+                    dat[5] = (hb>>8) & 0xff;
+                    __attribute__((fallthrough));
+                case 5:
+                    dat[4] = hb & 0xff;
+                    __attribute__((fallthrough));
+                case 4:
+                    dat[3] = lb>>24;
+                    __attribute__((fallthrough));
+                case 3:
+                    dat[2] = (lb>>16) & 0xff;
+                    __attribute__((fallthrough));
+                case 2:
+                    dat[1] = (lb>>8) & 0xff;
+                    __attribute__((fallthrough));
+                case 1:
+                    dat[0] = lb & 0xff;
+            }
+        }
+        if(CAN_messagebuf_push(&msg)) return; // error: buffer is full, try later
+        *RFxR |= CAN_RF0R_RFOM0; // release fifo for access to next message
+    }
+    //if(*RFxR & CAN_RF0R_FULL0) *RFxR &= ~CAN_RF0R_FULL0;
+    *RFxR = 0; // clear FOVR & FULL
+}
+
+void usb_lp_can_rx0_isr(){ // Rx FIFO0 (overrun)
+    if(CAN1->RF0R & CAN_RF0R_FOVR0){ // FIFO overrun
+        CAN1->RF0R &= ~CAN_RF0R_FOVR0;
+        can_status = CAN_FIFO_OVERRUN;
+    }
+}
+
+void can_rx1_isr(){ // Rx FIFO1 (overrun)
+    if(CAN1->RF1R & CAN_RF1R_FOVR1){
+        CAN1->RF1R &= ~CAN_RF1R_FOVR1;
+        can_status = CAN_FIFO_OVERRUN;
+    }
+}
+
+void can_sce_isr(){ // status changed
+    if(CAN1->MSR & CAN_MSR_ERRI){ // Error
+        CAN1->MSR &= ~CAN_MSR_ERRI;
+        // request abort for problem mailbox
+        if(CAN1->TSR & CAN_TSR_TERR0) CAN1->TSR |= CAN_TSR_ABRQ0;
+        if(CAN1->TSR & CAN_TSR_TERR1) CAN1->TSR |= CAN_TSR_ABRQ1;
+        if(CAN1->TSR & CAN_TSR_TERR2) CAN1->TSR |= CAN_TSR_ABRQ2;
+        can_status = CAN_ERR;
+    }
+}
diff --git a/F1:F103/FX3U/can.h b/F1:F103/FX3U/can.h
new file mode 100644
index 0000000..087bb75
--- /dev/null
+++ b/F1:F103/FX3U/can.h
@@ -0,0 +1,56 @@
+/*
+ * This file is part of the fx3u project.
+ * Copyright 2024 Edward V. Emelianov <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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+// amount of filter banks in STM32F0
+#define STM32F0FBANKNO      28
+// flood period in milliseconds
+#define FLOOD_PERIOD_MS     5
+
+// incoming message buffer size
+#define CAN_INMESSAGE_SIZE  (8)
+
+// CAN message
+typedef struct{
+    uint8_t data[8];    // up to 8 bytes of data
+    uint8_t length;     // data length
+    uint16_t ID;        // ID of receiver
+} CAN_message;
+
+typedef enum{
+    CAN_STOP,
+    CAN_READY,
+    CAN_BUSY,
+    CAN_OK,
+    CAN_ERR,
+    CAN_FIFO_OVERRUN
+} CAN_status;
+
+CAN_status CAN_get_status();
+
+void CAN_reinit(uint16_t speed);
+void CAN_setup(uint16_t speed);
+
+CAN_status can_send(uint8_t *msg, uint8_t len, uint16_t target_id);
+void can_proc();
+void printCANerr();
+
+CAN_message *CAN_messagebuf_pop();
diff --git a/F1:F103/FX3U/flash.c b/F1:F103/FX3U/flash.c
new file mode 100644
index 0000000..d81beea
--- /dev/null
+++ b/F1:F103/FX3U/flash.c
@@ -0,0 +1,191 @@
+/*
+ * This file is part of the fx3u project.
+ * Copyright 2024 Edward V. Emelianov <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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "stm32f1.h"
+
+#include "flash.h"
+#include "strfunc.h"
+#include "usart.h"
+#include <string.h> // memcpy
+
+extern const uint32_t __varsstart, _BLOCKSIZE;
+static const uint32_t FLASH_blocksize = (uint32_t)&_BLOCKSIZE;
+static uint32_t maxCnum = 1024 / sizeof(user_conf); // can't use blocksize here
+
+#define USERCONF_INITIALIZER  {         \
+     .userconf_sz = sizeof(user_conf)   \
+    ,.canspeed = 250                    \
+    ,.canID = 0xAA                      \
+    ,.rs232speed = 115200               \
+    }
+
+static int write2flash(const void*, const void*, uint32_t);
+const user_conf *Flash_Data = (const user_conf *)(&__varsstart);
+user_conf the_conf = USERCONF_INITIALIZER;
+
+static int currentconfidx = -1; // index of current configuration
+
+/**
+ * @brief binarySearch - binary search in flash for last non-empty cell
+ *          any struct searched should have its sizeof() @ the first field!!!
+ * @param l - left index
+ * @param r - right index (should be @1 less than last index!)
+ * @param start - starting address
+ * @param stor_size - size of structure to search
+ * @return index of non-empty cell or -1
+ */
+static int binarySearch(int r, const uint8_t *start, int stor_size){
+    int l = 0;
+    while(r >= l){
+        int mid = l + (r - l) / 2;
+        const uint8_t *s = start + mid * stor_size;
+        if(*((const uint16_t*)s) == stor_size){
+            if(*((const uint16_t*)(s + stor_size)) == 0xffff){ // next is free
+                return mid;
+            }else{ // element is to the right
+                l = mid + 1;
+            }
+        }else{ // element is to the left
+            r = mid - 1;
+        }
+    }
+    return -1; // not found
+}
+
+/**
+ * @brief flashstorage_init - initialization of user conf storage
+ * run in once @ start
+ */
+void flashstorage_init(){
+    if(FLASH_SIZE > 0 && FLASH_SIZE < 20000){
+        uint32_t flsz = FLASH_SIZE * 1024; // size in bytes
+        flsz -= (uint32_t)(&__varsstart) - FLASH_BASE;
+        maxCnum = flsz / sizeof(user_conf);
+    }
+    // -1 if there's no data at all & flash is clear; maxnum-1 if flash is full
+    currentconfidx = binarySearch((int)maxCnum-2, (const uint8_t*)Flash_Data, sizeof(user_conf));
+    if(currentconfidx > -1){
+        memcpy(&the_conf, &Flash_Data[currentconfidx], sizeof(user_conf));
+    }
+}
+
+// store new configuration
+// @return 0 if all OK
+int store_userconf(){
+    // maxnum - 3 means that there always should be at least one empty record after last data
+    // for binarySearch() checking that there's nothing more after it!
+    if(currentconfidx > (int)maxCnum - 3){ // there's no more place
+        currentconfidx = 0;
+        if(erase_storage(-1)) return 1;
+    }else ++currentconfidx; // take next data position (0 - within first run after firmware flashing)
+    return write2flash((const void*)&Flash_Data[currentconfidx], &the_conf, sizeof(the_conf));
+}
+
+static int write2flash(const void *start, const void *wrdata, uint32_t stor_size){
+    int ret = 0;
+    if (FLASH->CR & FLASH_CR_LOCK){ // unloch flash
+        FLASH->KEYR = FLASH_KEY1;
+        FLASH->KEYR = FLASH_KEY2;
+    }
+    while (FLASH->SR & FLASH_SR_BSY)  IWDG->KR = IWDG_REFRESH;
+    FLASH->SR = FLASH_SR_EOP | FLASH_SR_PGERR | FLASH_SR_WRPRTERR; // clear all flags
+    FLASH->CR |= FLASH_CR_PG;
+    const uint16_t *data = (const uint16_t*) wrdata;
+    volatile uint16_t *address = (volatile uint16_t*) start;
+    uint32_t i, count = (stor_size + 1) / 2;
+    for(i = 0; i < count; ++i){
+        *(volatile uint16_t*)(address + i) = data[i];
+        while(FLASH->SR & FLASH_SR_BSY) IWDG->KR = IWDG_REFRESH;
+        if(*(volatile uint16_t*)(address + i) != data[i]){
+            usart_send("DON'T MATCH!\n");
+            ret = 1;
+            break;
+        }
+        if(FLASH->SR & FLASH_SR_PGERR){
+            usart_send("Prog err\n");
+            ret = 1; // program error - meet not 0xffff
+            break;
+        }
+        FLASH->SR = FLASH_SR_EOP | FLASH_SR_PGERR | FLASH_SR_WRPRTERR;
+    }
+    FLASH->CR &= ~(FLASH_CR_PG);
+    return ret;
+}
+
+// erase Nth page of flash storage (flash should be prepared!)
+static int erase_pageN(int N){
+    int ret = 0;
+    FLASH->AR = (uint32_t)Flash_Data + N*FLASH_blocksize;
+    FLASH->CR |= FLASH_CR_STRT;
+    while(FLASH->SR & FLASH_SR_BSY) IWDG->KR = IWDG_REFRESH;
+    FLASH->SR = FLASH_SR_EOP;
+    if(FLASH->SR & FLASH_SR_WRPRTERR){ /* Check Write protection error */
+        ret = 1;
+        FLASH->SR = FLASH_SR_WRPRTERR; /* Clear the flag by software by writing it at 1*/
+    }
+    return ret;
+}
+
+// erase full storage (npage < 0) or its nth page; @return 0 if all OK
+int erase_storage(int npage){
+    int ret = 0;
+    uint32_t end = 1, start = 0, flsz = 0;
+    if(FLASH_SIZE > 0 && FLASH_SIZE < 20000){
+        flsz = FLASH_SIZE * 1024; // size in bytes
+        flsz -= (uint32_t)Flash_Data - FLASH_BASE;
+    }
+    end = flsz / FLASH_blocksize;
+#ifdef EBUG
+    usart_send("FLASH_SIZE="); usart_send(u2str(FLASH_SIZE));
+    usart_send("\nflsz="); usart_send(u2str(flsz));
+    usart_send("\nend="); usart_send(u2str(end));
+    usart_send("\ncurrentconfidx="); usart_send(u2str(currentconfidx));
+    usart_send("\nmaxCnum="); usart_send(u2str(maxCnum));
+    usart_send("\n");
+#endif
+    if(end == 0 || end >= FLASH_SIZE) return 1;
+    if(npage > -1){ // erase only one page
+        if((uint32_t)npage >= end) return 1;
+        start = npage;
+        end = start + 1;
+    }
+    if((FLASH->CR & FLASH_CR_LOCK) != 0){
+        FLASH->KEYR = FLASH_KEY1;
+        FLASH->KEYR = FLASH_KEY2;
+    }
+    while(FLASH->SR & FLASH_SR_BSY) IWDG->KR = IWDG_REFRESH;
+    FLASH->SR = FLASH_SR_EOP | FLASH_SR_PGERR | FLASH_SR_WRPRTERR;
+    FLASH->CR |= FLASH_CR_PER;
+    for(uint32_t i = start; i < end; ++i){
+        if(erase_pageN(i)){
+            ret = 1;
+            break;
+        }
+    }
+    FLASH->CR &= ~FLASH_CR_PER;
+    return ret;
+}
+
+void dump_userconf(){
+    usart_send("userconf_sz="); printu(the_conf.userconf_sz);
+    usart_send("\ncurrentconfidx="); usart_send(u2str(currentconfidx));
+    usart_send("\nCAN_speed="); printu(the_conf.canspeed);
+    usart_send("\nCAN_ID="); printu(the_conf.canID);
+    usart_send("\nRS_232_speed="); printu(the_conf.rs232speed);
+    usart_send("\n");
+}
diff --git a/F1:F103/FX3U/flash.h b/F1:F103/FX3U/flash.h
new file mode 100644
index 0000000..7e6baf8
--- /dev/null
+++ b/F1:F103/FX3U/flash.h
@@ -0,0 +1,41 @@
+/*
+ * This file is part of the fx3u project.
+ * Copyright 2024 Edward V. Emelianov <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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <stm32f1.h>
+
+#define FLASH_SIZE_REG      ((uint32_t)0x1FFFF7E0)
+#define FLASH_SIZE          *((uint16_t*)FLASH_SIZE_REG)
+
+/*
+ * struct to save user configurations
+ */
+typedef struct __attribute__((packed, aligned(4))){
+    uint16_t userconf_sz;       // "magick number"
+    uint16_t canspeed;          // CAN bus speed
+    uint16_t canID;             // CAN bus device ID
+    uint32_t rs232speed;        // speed of RS-232
+} user_conf;
+
+extern user_conf the_conf;
+
+void flashstorage_init();
+int store_userconf();
+int erase_storage(int npage);
+void dump_userconf();
diff --git a/F1:F103/FX3U/fx3u.cflags b/F1:F103/FX3U/fx3u.cflags
new file mode 100644
index 0000000..68d5165
--- /dev/null
+++ b/F1:F103/FX3U/fx3u.cflags
@@ -0,0 +1 @@
+-std=c17
\ No newline at end of file
diff --git a/F1:F103/FX3U/fx3u.config b/F1:F103/FX3U/fx3u.config
new file mode 100644
index 0000000..4a7b815
--- /dev/null
+++ b/F1:F103/FX3U/fx3u.config
@@ -0,0 +1,6 @@
+// Add predefined macros for your project here. For example:
+// #define THE_ANSWER 42
+#define EBUG
+#define STM32F1
+#define STM32F103xC
+#define STM32F10X_HD
diff --git a/F1:F103/FX3U/fx3u.creator b/F1:F103/FX3U/fx3u.creator
new file mode 100644
index 0000000..e94cbbd
--- /dev/null
+++ b/F1:F103/FX3U/fx3u.creator
@@ -0,0 +1 @@
+[General]
diff --git a/F1:F103/FX3U/fx3u.creator.user b/F1:F103/FX3U/fx3u.creator.user
new file mode 100644
index 0000000..2d3fcea
--- /dev/null
+++ b/F1:F103/FX3U/fx3u.creator.user
@@ -0,0 +1,180 @@
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diff --git a/F1:F103/FX3U/fx3u.creator.user.cf63021 b/F1:F103/FX3U/fx3u.creator.user.cf63021
new file mode 100644
index 0000000..ebefce4
--- /dev/null
+++ b/F1:F103/FX3U/fx3u.creator.user.cf63021
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diff --git a/F1:F103/FX3U/fx3u.cxxflags b/F1:F103/FX3U/fx3u.cxxflags
new file mode 100644
index 0000000..6435dfc
--- /dev/null
+++ b/F1:F103/FX3U/fx3u.cxxflags
@@ -0,0 +1 @@
+-std=c++17
\ No newline at end of file
diff --git a/F1:F103/FX3U/fx3u.files b/F1:F103/FX3U/fx3u.files
new file mode 100644
index 0000000..f964000
--- /dev/null
+++ b/F1:F103/FX3U/fx3u.files
@@ -0,0 +1,16 @@
+adc.c
+adc.h
+buttons.c
+can.c
+can.h
+flash.c
+flash.h
+hardware.c
+hardware.h
+main.c
+proto.c
+proto.h
+strfunc.c
+strfunc.h
+usart.c
+usart.h
diff --git a/F1:F103/FX3U/fx3u.includes b/F1:F103/FX3U/fx3u.includes
new file mode 100644
index 0000000..0dce01d
--- /dev/null
+++ b/F1:F103/FX3U/fx3u.includes
@@ -0,0 +1,7 @@
+.
+../inc
+../inc/Fx
+../inc/cm
+../inc/ld
+../inc/startup
+
diff --git a/F1:F103/FX3U/hardware.c b/F1:F103/FX3U/hardware.c
new file mode 100644
index 0000000..6b0a98f
--- /dev/null
+++ b/F1:F103/FX3U/hardware.c
@@ -0,0 +1,105 @@
+/*
+ * This file is part of the fx3u project.
+ * Copyright 2024 Edward V. Emelianov <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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "hardware.h"
+
+/* pinout:
+
+| **Pin #** | **Pin name ** | **function** | **settings**           | **comment **                            |
+| --------- | ------------- | ------------ | ---------------------- | --------------------------------------- |
+|  15       | PC0/adcin10   | ADC4         | ADC in                 |                                         |
+|  16       | PC1/adcin11   | ADC5         | ADC in                 |                                         |
+|  23       | PA0           | Y3           | PPOUT                  |                                         |
+|  24       | PA1/adcin1    | ADC0         | ADC in                 |                                         |
+|  25       | PA2           | Y11          | PPOUT                  |                                         |
+|  26       | PA3/adcin3    | ADC1         | ADC in                 |                                         |
+|  31       | PA6           | Y10          | PPOUT                  |                                         |
+|  32       | PA7           | Y7           | PPOUT                  |                                         |
+|  33       | PC4/adcin14   | ADC2         | ADC in                 |                                         |
+|  34       | PC5/adcin15   | ADC3         | ADC in                 |                                         |
+|  37       | PB2/boot1     | PROG SW      | PUIN                   |                                         |
+|  38       | PE7           | X14          | PUIN                   |                                         |
+|  39       | PE8           | X15          | PUIN                   |                                         |
+|  40       | PE9           | X12          | PUIN                   |                                         |
+|  41       | PE10          | X13          | PUIN                   |                                         |
+|  42       | PE11          | X10          | PUIN                   |                                         |
+|  43       | PE12          | X11          | PUIN                   |                                         |
+|  44       | PE13          | X6           | PUIN                   |                                         |
+|  45       | PE14          | X7           | PUIN                   |                                         |
+|  46       | PE15          | X4           | PUIN                   |                                         |
+|  47       | PB10          | X5           | PUIN                   |                                         |
+|  48       | PB11          | X2           | PUIN                   |                                         |
+|  51       | PB12          | X3           | PUIN                   |                                         |
+|  52       | PB13          | X0           | PUIN                   |                                         |
+|  53       | PB14          | X1           | PUIN                   |                                         |
+|  54       | PB15          | Y6           | PPOUT                  |                                         |
+|  59       | PD12          | Y5           | PPOUT                  |                                         |
+|  65       | PC8           | Y1           | PPOUT                  |                                         |
+|  66       | PC9           | Y0           | PPOUT                  |                                         |
+|  67       | PA8           | Y2           | PPOUT                  |                                         |
+|  68       | PA9           | RS TX        | AFPP                   |                                         |
+|  69       | PA10          | RS RX        | FLIN                   |                                         |
+|  76       | PA14/SWCLK    | 485 DE *     | (default)              | (Not now)                               |
+|  81       | PD0           | CAN RX       | FLIN                   |                                         |
+|  82       | PD1           | CAN TX       | AFPP                   |                                         |
+|  89       | PB3/JTDO      | Y4           | PPOUT                  |                                         |
+|           |               |              |                        |                                         |
+|           |               |              |                        |                                         |
+|           |               |              |                        |                                         |
+ */
+
+void gpio_setup(void){
+    // PD0 & PD1 (CAN) setup in can.c; PA9 & PA10 (USART) in usart.c
+    RCC->APB2ENR |= RCC_APB2ENR_IOPAEN | RCC_APB2ENR_IOPBEN | RCC_APB2ENR_IOPCEN | RCC_APB2ENR_IOPDEN |
+                    RCC_APB2ENR_IOPEEN | RCC_APB2ENR_AFIOEN;
+    // Turn off JTAG
+    AFIO->MAPR = AFIO_MAPR_SWJ_CFG_JTAGDISABLE;
+    GPIOA->CRL = CRL(0, CNF_PPOUTPUT|MODE_NORMAL) | CRL(1, CNF_ANALOG) | CRL(2, CNF_PPOUTPUT|MODE_NORMAL) |
+                 CRL(3, CNF_ANALOG) | CRL(6, CNF_PPOUTPUT|MODE_NORMAL) | CRL(7, CNF_PPOUTPUT|MODE_NORMAL);
+    GPIOA->CRH = 0;
+    GPIOB->CRL = CRL(2, CNF_PUDINPUT);
+    GPIOB->CRH = CRH(10, CNF_PUDINPUT) | CRH(11, CNF_PUDINPUT) | CRH(12, CNF_PUDINPUT) | CRH(13, CNF_PUDINPUT) |
+                 CRH(14, CNF_PUDINPUT) | CRH(15, CNF_PPOUTPUT|MODE_NORMAL);
+    GPIOC-> CRL = CRL(0, CNF_ANALOG) | CRL(1, CNF_ANALOG) | CRL(4, CNF_ANALOG) | CRL(5, CNF_ANALOG);
+    GPIOC->CRH = CRH(8, CNF_PPOUTPUT|MODE_NORMAL) | CRH(9, CNF_PPOUTPUT|MODE_NORMAL);
+    GPIOD->CRL = 0;
+    GPIOD->CRH = CRH(12, CNF_PPOUTPUT|MODE_NORMAL);
+    GPIOE->CRL = CRL(7, CNF_PUDINPUT);
+    GPIOE->CRH = CRH(8, CNF_PUDINPUT) | CRH(9, CNF_PUDINPUT) | CRH(10, CNF_PUDINPUT) | CRH(11, CNF_PUDINPUT) |
+                 CRH(12, CNF_PUDINPUT) | CRH(13, CNF_PUDINPUT) | CRH(14, CNF_PUDINPUT) | CRH(15, CNF_PUDINPUT);
+    // pullups & initial values
+    GPIOA->ODR = 0;
+    GPIOB->ODR = (1<<2) | (1<<10) | (1<<11) | (1<<12) | (1<<13) | (1<<14);
+    GPIOC->ODR = 0;
+    GPIOD->ODR = 0;
+    GPIOE->ODR = (1<<7) | (1<<8) | (1<<9) | (1<<10) | (1<<11) | (1<<12) | (1<<13) | (1<<14) | (1<<15);
+}
+
+
+void iwdg_setup(){
+    uint32_t tmout = 16000000;
+    RCC->CSR |= RCC_CSR_LSION;
+    while((RCC->CSR & RCC_CSR_LSIRDY) != RCC_CSR_LSIRDY){if(--tmout == 0) break;}
+    IWDG->KR = IWDG_START;
+    IWDG->KR = IWDG_WRITE_ACCESS;
+    IWDG->PR = IWDG_PR_PR_1;
+    IWDG->RLR = 1250;
+    tmout = 16000000;
+    while(IWDG->SR){if(--tmout == 0) break;}
+    IWDG->KR = IWDG_REFRESH;
+}
diff --git a/F1:F103/FX3U/hardware.h b/F1:F103/FX3U/hardware.h
new file mode 100644
index 0000000..d90dcec
--- /dev/null
+++ b/F1:F103/FX3U/hardware.h
@@ -0,0 +1,33 @@
+/*
+ * This file is part of the fx3u project.
+ * Copyright 2024 Edward V. Emelianov <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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <stm32f1.h>
+
+#define CONCAT(a,b)     a ## b
+#define STR_HELPER(s)   #s
+#define STR(s)          STR_HELPER(s)
+
+#define FORMUSART(X)    CONCAT(USART, X)
+#define USARTX          FORMUSART(USARTNUM)
+
+extern volatile uint32_t Tms;
+
+void gpio_setup(void);
+void iwdg_setup();
diff --git a/F1:F103/FX3U/main.c b/F1:F103/FX3U/main.c
new file mode 100644
index 0000000..61880d3
--- /dev/null
+++ b/F1:F103/FX3U/main.c
@@ -0,0 +1,84 @@
+/*
+ * This file is part of the fx3u project.
+ * Copyright 2024 Edward V. Emelianov <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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "adc.h"
+#include "can.h"
+#include "flash.h"
+#include "hardware.h"
+#include "proto.h"
+#include "strfunc.h"
+
+volatile uint32_t Tms = 0;
+
+/* Called when systick fires */
+void sys_tick_handler(void){
+    ++Tms;
+}
+
+int main(void){
+    uint32_t lastT = 0;
+    CAN_message *can_mesg;
+    StartHSE();
+    SysTick_Config(72000);
+    flashstorage_init();
+    gpio_setup(); // should be run before other peripherial setup
+    adc_setup();
+    usart_setup(the_conf.rs232speed);
+    CAN_setup(the_conf.canspeed);
+    RCC->CSR |= RCC_CSR_RMVF; // remove reset flags
+#ifndef EBUG
+    iwdg_setup();
+#endif
+    while (1){
+        IWDG->KR = IWDG_REFRESH; // refresh watchdog
+        if(Tms - lastT > 499){ // throw out short messages twice per second
+            usart_transmit();
+            lastT = Tms;
+        }
+        can_proc();
+        CAN_status st = CAN_get_status();
+        if(st == CAN_FIFO_OVERRUN){
+            usart_send("CAN bus fifo overrun occured!\n");
+        }else if(st == CAN_ERR){
+            usart_send("Some CAN error occured\n");
+        }
+        while((can_mesg = CAN_messagebuf_pop())){
+            IWDG->KR = IWDG_REFRESH;
+            // TODO: check ID and process messages
+            if(flags.can_monitor){
+                lastT = Tms;
+                if(!lastT) lastT = 1;
+                uint8_t len = can_mesg->length;
+                printu(Tms);
+                usart_send(" #");
+                printuhex(can_mesg->ID);
+                for(uint8_t ctr = 0; ctr < len; ++ctr){
+                    usart_putchar(' ');
+                    printuhex(can_mesg->data[ctr]);
+                }
+                usart_putchar('\n');
+            }
+        }
+        char *str;
+        int g = usart_getline(&str);
+        if(g < 0) usart_send("USART IN buffer overflow!\n");
+        else if(g > 0) cmd_parser(str);
+    }
+    return 0;
+}
+
diff --git a/F1:F103/FX3U/openocd.cfg b/F1:F103/FX3U/openocd.cfg
new file mode 100644
index 0000000..5f64fe2
--- /dev/null
+++ b/F1:F103/FX3U/openocd.cfg
@@ -0,0 +1,6 @@
+# STM32F103VC
+
+set FLASH_SIZE 0x40000
+
+source [find interface/stlink-v2-1.cfg]
+source [find target/stm32f1x.cfg]
diff --git a/F1:F103/FX3U/proto.c b/F1:F103/FX3U/proto.c
new file mode 100644
index 0000000..4b7e6b5
--- /dev/null
+++ b/F1:F103/FX3U/proto.c
@@ -0,0 +1,54 @@
+/*
+ * This file is part of the fx3u project.
+ * Copyright 2024 Edward V. Emelianov <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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "adc.h"
+#include "can.h"
+#include "hardware.h"
+#include "proto.h"
+#include "strfunc.h"
+#include "usart.h"
+#include "version.inc"
+
+flags_t flags = {
+    .can_monitor = 0
+};
+
+static void printans(int res){
+    if(res) usart_send("OK");
+    else usart_send("FAIL");
+}
+
+// setters of uint/int
+static void usetter(int(*fn)(uint32_t), char* str){
+    uint32_t d = 0;
+    if(str == getnum(str, &d)) printans(FALSE);
+    else printans(fn(d));
+}
+static void isetter(int(*fn)(int32_t), char* str){
+    int32_t d = 0;
+    if(str == getint(str, &d)) printans(FALSE);
+    else printans(fn(d));
+}
+
+/**
+ * @brief cmd_parser - command parsing
+ * @param txt   - buffer with commands & data
+ */
+void cmd_parser(char *txt){
+    (void)txt;
+}
diff --git a/F1:F103/FX3U/proto.h b/F1:F103/FX3U/proto.h
new file mode 100644
index 0000000..023471a
--- /dev/null
+++ b/F1:F103/FX3U/proto.h
@@ -0,0 +1,40 @@
+/*
+ * This file is part of the fx3u project.
+ * Copyright 2024 Edward V. Emelianov <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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <stm32f1.h>
+#include "hardware.h"
+
+#define BUFSZ   (64)
+
+typedef struct{
+    uint32_t can_monitor : 1;
+} flags_t;
+
+extern flags_t flags;
+
+#ifdef EBUG
+#define DBG(str)  do{usart_send(__FILE__ " (L" STR(__LINE__) "): " str); \
+    usart_putchar('\n'); usart_transmit(); }while(0)
+#else
+#define DBG(str)
+#endif
+
+
+void cmd_parser(char *buf);
diff --git a/F1:F103/FX3U/strfunc.c b/F1:F103/FX3U/strfunc.c
new file mode 100644
index 0000000..7c42a70
--- /dev/null
+++ b/F1:F103/FX3U/strfunc.c
@@ -0,0 +1,268 @@
+/*
+ * This file is part of the fx3u project.
+ * Copyright 2024 Edward V. Emelianov <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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stm32f1.h>
+#include <string.h>
+
+/**
+ * @brief hexdump - dump hex array by 16 bytes in string
+ * @param sendfun - function to send data
+ * @param arr - array to dump
+ * @param len - length of `arr`
+ */
+void hexdump(int (*sendfun)(const char *s), uint8_t *arr, uint16_t len){
+    char buf[52], *bptr = buf;
+    for(uint16_t l = 0; l < len; ++l, ++arr){
+        for(int16_t j = 1; j > -1; --j){
+            register uint8_t half = (*arr >> (4*j)) & 0x0f;
+            if(half < 10) *bptr++ = half + '0';
+            else *bptr++ = half - 10 + 'a';
+        }
+        if(l % 16 == 15){
+            *bptr++ = '\n';
+            *bptr = 0;
+            sendfun(buf);
+            bptr = buf;
+        }else *bptr++ = ' ';
+    }
+    if(bptr != buf){
+        *bptr++ = '\n';
+        *bptr = 0;
+        sendfun(buf);
+    }
+}
+
+/**
+ * @brief _2str - convert value into string buffer
+ * @param val - |value|
+ * @param minus - ==0 if value > 0
+ * @return buffer with number
+ */
+static char *_2str(uint32_t  val, uint8_t minus){
+    static char strbuf[12];
+    char *bufptr = &strbuf[11];
+    *bufptr = 0;
+    if(!val){
+        *(--bufptr) = '0';
+    }else{
+        while(val){
+            uint32_t x = val / 10;
+            *(--bufptr) = (val - 10*x) + '0';
+            val = x;
+            //*(--bufptr) = val % 10 + '0';
+            //val /= 10;
+        }
+    }
+    if(minus) *(--bufptr) = '-';
+    return bufptr;
+}
+
+// return string with number `val`
+char *u2str(uint32_t val){
+    return _2str(val, 0);
+}
+char *i2str(int32_t i){
+    uint8_t minus = 0;
+    uint32_t val;
+    if(i < 0){
+        minus = 1;
+        val = -i;
+    }else val = i;
+    return _2str(val, minus);
+}
+
+/**
+ * @brief uhex2str - print 32bit unsigned int as hex
+ * @param val - value
+ * @return string with number
+ */
+char *uhex2str(uint32_t val){
+    static char buf[12] = "0x";
+    int npos = 2;
+    uint8_t *ptr = (uint8_t*)&val + 3;
+    int8_t i, j, z=1;
+    for(i = 0; i < 4; ++i, --ptr){
+        if(*ptr == 0){ // omit leading zeros
+            if(i == 3) z = 0;
+            if(z) continue;
+        }
+        else z = 0;
+        for(j = 1; j > -1; --j){
+            uint8_t half = (*ptr >> (4*j)) & 0x0f;
+            if(half < 10) buf[npos++] = half + '0';
+            else buf[npos++] = half - 10 + 'a';
+        }
+    }
+    buf[npos] = 0;
+    return buf;
+}
+
+/**
+ * @brief omit_spaces - eliminate leading spaces and other trash in string
+ * @param buf - string
+ * @return - pointer to first character in `buf` > ' '
+ */
+const char *omit_spaces(const char *buf){
+    while(*buf){
+        if(*buf > ' ') break;
+        ++buf;
+    }
+    return buf;
+}
+
+/**
+ * @brief getdec - read decimal number & return pointer to next non-number symbol
+ * @param buf - string
+ * @param N - number read
+ * @return Next non-number symbol. In case of overflow return `buf` and N==0xffffffff
+ */
+static const char *getdec(const char *buf, uint32_t *N){
+    char *start = (char*)buf;
+    uint32_t num = 0;
+    while(*buf){
+        char c = *buf;
+        if(c < '0' || c > '9'){
+            break;
+        }
+        if(num > 429496729 || (num == 429496729 && c > '5')){ // overflow
+            *N = 0xffffff;
+            return start;
+        }
+        num *= 10;
+        num += c - '0';
+        ++buf;
+    }
+    *N = num;
+    return buf;
+}
+// read hexadecimal number (without 0x prefix!)
+static const char *gethex(const char *buf, uint32_t *N){
+    const char *start = buf;
+    uint32_t num = 0;
+    while(*buf){
+        char c = *buf;
+        uint8_t M = 0;
+        if(c >= '0' && c <= '9'){
+            M = '0';
+        }else if(c >= 'A' && c <= 'F'){
+            M = 'A' - 10;
+        }else if(c >= 'a' && c <= 'f'){
+            M = 'a' - 10;
+        }
+        if(M){
+            if(num & 0xf0000000){ // overflow
+                *N = 0xffffff;
+                return start;
+            }
+            num <<= 4;
+            num += c - M;
+        }else{
+            break;
+        }
+        ++buf;
+    }
+    *N = num;
+    return buf;
+}
+// read octal number (without 0 prefix!)
+static const char *getoct(const char *buf, uint32_t *N){
+    const char *start = (char*)buf;
+    uint32_t num = 0;
+    while(*buf){
+        char c = *buf;
+        if(c < '0' || c > '7'){
+            break;
+        }
+        if(num & 0xe0000000){ // overflow
+            *N = 0xffffff;
+            return start;
+        }
+        num <<= 3;
+        num += c - '0';
+        ++buf;
+    }
+    *N = num;
+    return buf;
+}
+// read binary number (without b prefix!)
+static const char *getbin(const char *buf, uint32_t *N){
+    const char *start = (char*)buf;
+    uint32_t num = 0;
+    while(*buf){
+        char c = *buf;
+        if(c < '0' || c > '1'){
+            break;
+        }
+        if(num & 0x80000000){ // overflow
+            *N = 0xffffff;
+            return start;
+        }
+        num <<= 1;
+        if(c == '1') num |= 1;
+        ++buf;
+    }
+    *N = num;
+    return buf;
+}
+
+/**
+ * @brief getnum - read uint32_t from string (dec, hex or bin: 127, 0x7f, 0b1111111)
+ * @param buf - buffer with number and so on
+ * @param N   - the number read
+ * @return pointer to first non-number symbol in buf
+ *      (if it is == buf, there's no number or if *N==0xffffffff there was overflow)
+ */
+const char *getnum(const char *txt, uint32_t *N){
+    const char *nxt = NULL;
+    const char *s = omit_spaces(txt);
+    if(*s == '0'){ // hex, oct or 0
+        if(s[1] == 'x' || s[1] == 'X'){ // hex
+            nxt = gethex(s+2, N);
+            if(nxt == s+2) nxt = (char*)txt;
+        }else if(s[1] > '0'-1 && s[1] < '8'){ // oct
+            nxt = getoct(s+1, N);
+            if(nxt == s+1) nxt = (char*)txt;
+        }else{ // 0
+            nxt = s+1;
+            *N = 0;
+        }
+    }else if(*s == 'b' || *s == 'B'){
+        nxt = getbin(s+1, N);
+        if(nxt == s+1) nxt = (char*)txt;
+    }else{
+        nxt = getdec(s, N);
+        if(nxt == s) nxt = (char*)txt;
+    }
+    return nxt;
+}
+
+// get signed integer
+const char *getint(const char *txt, int32_t *I){
+    const char *s = omit_spaces(txt);
+    int32_t sign = 1;
+    uint32_t U;
+    if(*s == '-'){
+    	sign = -1;
+    	++s;
+    }
+    const char *nxt = getnum(s, &U);
+    if(nxt == s) return txt;
+    if(U & 0x80000000) return txt; // overfull
+    *I = sign * (int32_t)U;
+    return nxt;
+}
diff --git a/F1:F103/FX3U/strfunc.h b/F1:F103/FX3U/strfunc.h
new file mode 100644
index 0000000..3be4040
--- /dev/null
+++ b/F1:F103/FX3U/strfunc.h
@@ -0,0 +1,37 @@
+/*
+ * This file is part of the fx3u project.
+ * Copyright 2024 Edward V. Emelianov <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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <string.h>
+
+#include "usart.h"
+
+void hexdump(int (*sendfun)(const char *s), uint8_t *arr, uint16_t len);
+char *u2str(uint32_t val);
+char *i2str(int32_t i);
+char *uhex2str(uint32_t val);
+const char *getnum(const char *txt, uint32_t *N);
+const char *omit_spaces(const char *buf);
+const char *getint(const char *txt, int32_t *I);
+
+#define newline() do{usart_putchar('\n');}while(0)
+#define printu(a) do{usart_send(u2str(a));}while(0)
+#define printi(a) do{usart_send(i2str(a));}while(0)
+#define printuhex(a) do{usart_send(uhex2str(a));}while(0)
diff --git a/F1:F103/FX3U/usart.c b/F1:F103/FX3U/usart.c
new file mode 100644
index 0000000..7dffdeb
--- /dev/null
+++ b/F1:F103/FX3U/usart.c
@@ -0,0 +1,152 @@
+/*
+ * This file is part of the fx3u project.
+ * Copyright 2024 Edward V. Emelianov <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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stm32f1.h>
+#include "usart.h"
+
+extern volatile uint32_t Tms;
+static volatile int idatalen[2] = {0,0}; // received data line length (including '\n')
+static volatile int odatalen[2] = {0,0};
+
+volatile int usart_txrdy = 1;   // transmission done
+
+static volatile int usart_linerdy = 0   // received data ready
+    ,dlen = 0                           // length of data (including '\n') in current buffer
+    ,usart_bufovr = 0                   // input buffer overfull
+
+;
+
+int rbufno = 0, tbufno = 0; // current rbuf/tbuf numbers
+static char rbuf[2][UARTBUFSZI], tbuf[2][UARTBUFSZO]; // receive & transmit buffers
+static char *recvdata = NULL;
+
+/**
+ * return length of received data (without trailing zero)
+ */
+int usart_getline(char **line){
+    if(usart_bufovr){
+        usart_bufovr = 0;
+        usart_linerdy = 0;
+        return -1;
+    }
+    if(!usart_linerdy) return 0;
+    *line = recvdata;
+    usart_linerdy = 0;
+    int x = dlen;
+    dlen = 0;
+    return x;
+}
+
+// transmit current tbuf and swap buffers
+int usart_transmit(){
+    register int l = odatalen[tbufno];
+    if(!l) return 0;
+    uint32_t tmout = 1600000;
+    while(!usart_txrdy){
+        IWDG->KR = IWDG_REFRESH;
+        if(--tmout == 0) return 0;
+    }; // wait for previos buffer transmission
+    usart_txrdy = 0;
+    odatalen[tbufno] = 0;
+    DMA1_Channel4->CCR &= ~DMA_CCR_EN;
+    DMA1_Channel4->CMAR = (uint32_t) tbuf[tbufno]; // mem
+    DMA1_Channel4->CNDTR = l;
+    DMA1_Channel4->CCR |= DMA_CCR_EN;
+    tbufno = !tbufno;
+    return l;
+}
+
+int usart_putchar(const char ch){
+    if(odatalen[tbufno] == UARTBUFSZO){
+        if(!usart_transmit()) return 0;
+    }
+    tbuf[tbufno][odatalen[tbufno]++] = ch;
+    return 1;
+}
+
+int usart_send(const char *str){
+    int l = 0;
+    while(*str){
+        if(odatalen[tbufno] == UARTBUFSZO){
+            if(!usart_transmit()) return 0;
+        }
+        tbuf[tbufno][odatalen[tbufno]++] = *str++;
+        ++l;
+    }
+    return l;
+}
+
+/*
+ * USART speed: baudrate = Fck/(USARTDIV)
+ * USARTDIV stored in USART->BRR
+ *
+ * for 72MHz USARTDIV=72000/f(kboud); so for 115200 USARTDIV=72000/115.2=625 -> BRR=0x271
+ *         9600: BRR = 7500 (0x1D4C)
+ */
+
+void usart_setup(uint32_t speed){
+    uint32_t tmout = 16000000;
+    // PA9 - Tx, PA10 - Rx
+    RCC->APB2ENR |= RCC_APB2ENR_USART1EN;
+    RCC->AHBENR |= RCC_AHBENR_DMA1EN;
+    GPIOA->CRH = (GPIOA->CRH & ~(CRH(9,0xf)|CRH(10,0xf))) |
+        CRH(9, CNF_AFPP|MODE_NORMAL) | CRH(10, CNF_FLINPUT|MODE_INPUT);
+    // USART1 Tx DMA - Channel4 (Rx - channel 5)
+    DMA1_Channel4->CPAR = (uint32_t) &USART1->DR; // periph
+    DMA1_Channel4->CCR |= DMA_CCR_MINC | DMA_CCR_DIR | DMA_CCR_TCIE; // 8bit, mem++, mem->per, transcompl irq
+    // Tx CNDTR set @ each transmission due to data size
+    NVIC_SetPriority(DMA1_Channel4_IRQn, 3);
+    NVIC_EnableIRQ(DMA1_Channel4_IRQn);
+    NVIC_SetPriority(USART1_IRQn, 0);
+    // setup usart1
+    USART1->BRR = 72000000 / speed;
+    USART1->CR1 = USART_CR1_TE | USART_CR1_RE | USART_CR1_UE; // 1start,8data,nstop; enable Rx,Tx,USART
+    while(!(USART1->SR & USART_SR_TC)){if(--tmout == 0) break;} // polling idle frame Transmission
+    USART1->SR = 0; // clear flags
+    USART1->CR1 |= USART_CR1_RXNEIE; // allow Rx IRQ
+    USART1->CR3 = USART_CR3_DMAT; // enable DMA Tx
+    NVIC_EnableIRQ(USART1_IRQn);
+}
+
+
+void usart1_isr(){
+    if(USART1->SR & USART_SR_RXNE){ // RX not emty - receive next char
+        uint8_t rb = USART1->DR;
+        if(idatalen[rbufno] < UARTBUFSZI){ // put next char into buf
+            if(rb == '\n'){ // got newline - line ready
+                rbuf[rbufno][idatalen[rbufno]] = 0;
+                usart_linerdy = 1;
+                dlen = idatalen[rbufno];
+                recvdata = rbuf[rbufno];
+                // prepare other buffer
+                rbufno = !rbufno;
+                idatalen[rbufno] = 0;
+            }else rbuf[rbufno][idatalen[rbufno]++] = rb;
+        }else{ // buffer overrun
+            usart_bufovr = 1;
+            idatalen[rbufno] = 0;
+        }
+    }
+}
+
+void dma1_channel4_isr(){
+    if(DMA1->ISR & DMA_ISR_TCIF4){ // Tx
+        DMA1->IFCR = DMA_IFCR_CTCIF4; // clear TC flag
+        usart_txrdy = 1;
+    }
+}
diff --git a/F1:F103/FX3U/usart.h b/F1:F103/FX3U/usart.h
new file mode 100644
index 0000000..ef767df
--- /dev/null
+++ b/F1:F103/FX3U/usart.h
@@ -0,0 +1,34 @@
+/*
+ * This file is part of the fx3u project.
+ * Copyright 2024 Edward V. Emelianov <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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+// input and output buffers size
+#define UARTBUFSZI  (64)
+#define UARTBUFSZO  (128)
+
+#define usartrx()  (usart_linerdy)
+#define usartovr() (usart_bufovr)
+
+extern volatile int usart_txrdy;
+
+int usart_transmit();
+void usart_setup(uint32_t speed);
+int usart_getline(char **line);
+int usart_send(const char *str);
+int usart_putchar(const char ch);
diff --git a/F1:F103/FX3U/version.inc b/F1:F103/FX3U/version.inc
new file mode 100644
index 0000000..249941c
--- /dev/null
+++ b/F1:F103/FX3U/version.inc
@@ -0,0 +1,2 @@
+#define BUILD_NUMBER "5"
+#define BUILD_DATE "2024-05-29"