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Add HTU-21d for NUCLEO

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eddyem 2017-03-01 21:58:33 +03:00
parent 89294084e6
commit 54a9e365ff
10 changed files with 762 additions and 1 deletions
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4
F0-nolib/Readme.md
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@ -4,6 +4,8 @@ Samples for STM32F042-nucleo and chinese STM32F030-based devboard
This directory contains examples for F0 without any library This directory contains examples for F0 without any library
- blink - simple LED blink - blink - simple LED blink
- htu21d_nucleo - operaing with HTU-21D in STM32F042-nucleo
- morze - for STM32F030, echo data from USART1 on TIM3CH1 (PA6) as Morze code
- uart - USART over DMA with hardware end-of-string detection - uart - USART over DMA with hardware end-of-string detection
- uart_blink - code for STM32F030F4, echo data on USART1 and blink LEDS on PA4 and PA5 - uart_blink - code for STM32F030F4, echo data on USART1 and blink LEDS on PA4 and PA5
- morze - for STM32F030, echo data from USART1 on TIM3CH1 (PA6) as Morze code - uart_nucleo - USART over DMA for STM32F042-nucleo

137
F0-nolib/htu21d_nucleo/Makefile Normal file
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BINARY = usart
BOOTPORT ?= /dev/ttyUSB0
BOOTSPEED ?= 115200
# MCU FAMILY
FAMILY = F0
# MCU code
MCU = F042x6
DEFS += -DEBUG
# change this linking script depending on particular MCU model,
# for example, if you have STM32F103VBT6, you should write:
LDSCRIPT = ld/stm32f042k.ld
INDEPENDENT_HEADERS=
FP_FLAGS ?= -msoft-float
ASM_FLAGS = -mthumb -mcpu=cortex-m0 -march=armv6-m -mtune=cortex-m0
ARCH_FLAGS = $(ASM_FLAGS) $(FP_FLAGS)
###############################################################################
# Executables
PREFIX ?= /opt/bin/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
OBJDIR = mk
LDSCRIPT ?= $(BINARY).ld
SRC := $(wildcard *.c)
OBJS := $(addprefix $(OBJDIR)/, $(SRC:%.c=%.o))
STARTUP = $(OBJDIR)/startup.o
OBJS += $(STARTUP)
DEPS := $(OBJS:.o=.d)
INC_DIR ?= ../inc
INCLUDE := -I$(INC_DIR)/F0 -I$(INC_DIR)/cm
LIB_DIR := $(INC_DIR)/ld
###############################################################################
# C flags
CFLAGS += -O2 -g -MD -D__thumb2__=1
CFLAGS += -Wall -Wextra -Wshadow -Wimplicit-function-declaration
CFLAGS += -Wredundant-decls $(INCLUDE)
# -Wmissing-prototypes -Wstrict-prototypes
CFLAGS += -fno-common -ffunction-sections -fdata-sections
###############################################################################
# Linker flags
LDFLAGS += --static -nostartfiles
#--specs=nano.specs
LDFLAGS += -L$(LIB_DIR)
LDFLAGS += -T$(LDSCRIPT)
LDFLAGS += -Wl,-Map=$(OBJDIR)/$(BINARY).map
LDFLAGS += -Wl,--gc-sections
###############################################################################
# Used libraries
LDLIBS += -Wl,--start-group -lc -lgcc -Wl,--end-group
LDLIBS += $(shell $(CC) $(CFLAGS) -print-libgcc-file-name)
DEFS += -DSTM32$(FAMILY) -DSTM32$(MCU)
#.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 list
elf: $(ELF)
bin: $(BIN)
hex: $(HEX)
list: $(LIST)
ifneq ($(MAKECMDGOALS),clean)
-include $(DEPS)
endif
$(OBJDIR):
mkdir $(OBJDIR)
$(STARTUP): $(INC_DIR)/startup/vector.c
$(CC) $(CFLAGS) $(DEFS) $(INCLUDE) $(ARCH_FLAGS) -o $@ -c $<
$(OBJDIR)/%.o: %.c
@echo " CC $<"
$(CC) $(CFLAGS) $(DEFS) $(INCLUDE) $(ARCH_FLAGS) -o $@ -c $<
#$(OBJDIR)/%.d: %.c $(OBJDIR)
# $(CC) -MM -MG $< | sed -e 's,^\([^:]*\)\.o[ ]*:,$(@D)/\1.o $(@D)/\1.d:,' >$@
$(BIN): $(ELF)
@echo " OBJCOPY $(BIN)"
$(OBJCOPY) -Obinary $(ELF) $(BIN)
$(HEX): $(ELF)
@echo " OBJCOPY $(HEX)"
$(OBJCOPY) -Oihex $(ELF) $(HEX)
$(LIST): $(ELF)
@echo " OBJDUMP $(LIST)"
$(OBJDUMP) -S $(ELF) > $(LIST)
$(ELF): $(OBJDIR) $(OBJS)
@echo " LD $(ELF)"
$(LD) $(LDFLAGS) $(ARCH_FLAGS) $(OBJS) $(LDLIBS) -o $(ELF)
clean:
@echo " CLEAN"
$(RM) $(OBJS) $(DEPS) $(ELF) $(HEX) $(LIST) $(OBJDIR)/*.map
@rmdir $(OBJDIR) 2>/dev/null || true
flash: $(BIN)
@echo " FLASH $(BIN)"
$(STFLASH) write $(BIN) 0x8000000
boot: $(BIN)
@echo " LOAD $(BIN) through bootloader"
$(STBOOT) -b$(BOOTSPEED) $(BOOTPORT) -w $(BIN)
.PHONY: clean flash boot

5
F0-nolib/htu21d_nucleo/Readme Normal file
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@ -0,0 +1,5 @@
Example for STM32F042 nucleo working with HTU-21D humidity/temperature sensor.
Every 1 second check humidity/temperature and show values by USART.
USART speed 115200.

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F0-nolib/htu21d_nucleo/i2c.c Normal file
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/*
* geany_encoding=koi8-r
* i2c.c
*
* Copyright 2017 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 "stm32f0.h"
#include "i2c.h"
/**
* I2C for HTU21D
* Speed <= 400kHz (200)
* t_SCLH ~ 0.6us
* t_SCLL ~ 1.3us
* t_SU >= 100ns
* t_HD <= 900ns
* t_VD <= 400ns
*
* After start 15ms pause for IDLE
* Start bit: SCK=1, DATA 1->0
* Stop bit: SCK 0->1, DATA 0->1
* Address: 0x40 (7bit), 0th bit - direction (0 - write, 1 - read)
* ACK: DATA->0 on 8th SCK clock
* Commands: 0xE3[F3] - temperature, 0xE5[F5] - humidity [No hold master]
* 0xE6 - write user register, 0xE7 - read user register, 0xFE - soft reset
* 7 6 5 4 3 2 1 0
* User register: |D1|Vbat|reserved|Htr|Odis|D0| default: 0x02
* D1D0 - resolution [H/T]: 00-12/14, 01-8/12, 10-10/13, 11-11/11
* Vbat=1 vhen Vdd<2.25V, Htr=1 to enable on-chip heater,
* Odis=0 to enable OTP reload (after each measurement reload defaults)
*
* in = in & 0xFFFC;
* Calculations: RH = -6 + 125*Hum/2^16
* T = -46.85 + 175.72*Temp/2^16
*/
/*
* Resources: I2C1_SCL - PA9, I2C1_SDA - PA10
* GPIOA->AFR[1] AF4 -- GPIOA->AFR[1] &= ~0xff0, GPIOA->AFR[1] |= 0x440
*/
extern volatile uint32_t Tms;
static uint32_t cntr;
void i2c_setup(){
// GPIO
RCC->AHBENR |= RCC_AHBENR_GPIOAEN; // clock
GPIOA->AFR[1] &= ~0xff0; // alternate function F4 for PA9/PA10
GPIOA->AFR[1] |= 0x440;
GPIOA->OTYPER |= GPIO_OTYPER_OT_9 | GPIO_OTYPER_OT_10; // opendrain
GPIOA->MODER &= ~(GPIO_MODER_MODER9 | GPIO_MODER_MODER10);
GPIOA->MODER |= GPIO_MODER_MODER9_AF | GPIO_MODER_MODER10_AF; // alternate function
// I2C
RCC->APB1ENR |= RCC_APB1ENR_I2C1EN; // timing
RCC->CFGR3 |= RCC_CFGR3_I2C1SW; // use sysclock for timing
// Clock = 6MHz, 0.16(6)us, need 5us (*30)
// PRESC=4 (f/5), SCLDEL=0 (t_SU=5/6us), SDADEL=0 (t_HD=5/6us), SCLL,SCLH=14 (2.(3)us)
I2C1->TIMINGR = (4<<28) | (14<<8) | (14); // 0x40000e0e
I2C1->CR1 = I2C_CR1_PE;// | I2C_CR1_RXIE; // Enable I2C & (interrupt on receive - not supported yet)
}
// I2C2->TIMINGR = (uint32_t)0x00B01A4B;
// PRECS=0 - tpresc=20.8(3)ns, SCLDEL=B (tSU 12tpresc), SDADEL=0 (tHD=0), SCLH=1a (27), SCLL=4B (76)
// https://github.com/mattbrejza/magnet-node/blob/master/firmware-basestation/htu21.c
// prescaler = 1, low period = 0x13, high period = 0xf, hold time = 2, setup = 4
// I2C_TIMINGR(H_I2C) = (1<<28) | (4<<20) | (2<<16) | (0xf<<8) | 0x13;
/* transmit:
* I2Cx_CR2:
* Addressing mode (7-bit or 10-bit): ADD10
* Slave address to be sent: SADD[9:0]
* Transfer direction: I2C_CR2_RD_WRN=0
* The number of bytes to be transferred: NBYTES[7:0] (NBYTES<<16)
* You must then set the START bit in I2Cx_CR2 register.
* Automatic end mode (AUTOEND = '1' in the I2Cx_CR2 register),
* I2C1->CR2 = I2C_CR2_HEAD10R | SLAVE_ADDR; // 7bit, slave address
*/
// return 1 if all OK, 0 if NACK
uint8_t htu_write_i2c(uint8_t data){
cntr = Tms;
while(I2C1->ISR & I2C_ISR_BUSY) if(Tms - cntr > 5) return 0; // check busy
cntr = Tms;
while(I2C1->CR2 & I2C_CR2_START) if(Tms - cntr > 5) return 0; // check start
I2C1->CR2 = 1<<16 | HTU21_ADDR | I2C_CR2_AUTOEND; // 1 byte, autoend
// now start transfer
I2C1->CR2 |= I2C_CR2_START;
cntr = Tms;
while(!(I2C1->ISR & I2C_ISR_TXIS)){ // ready to transmit
if(I2C1->ISR & I2C_ISR_NACKF){
I2C1->ICR |= I2C_ICR_NACKCF;
return 0;
}
if(Tms - cntr > 5) return 0;
}
I2C1->TXDR = data; // send data
return 1;
}
#define SHIFTED_DIVISOR 0x988000 //This is the 0x0131 polynomial shifted to farthest left of three bytes
// check CRC, return 0 if all OK
uint32_t htu_check_crc(uint16_t data, uint8_t crc){
uint32_t remainder = (uint32_t)data << 8;
remainder |= crc;
uint32_t divsor = (uint32_t)SHIFTED_DIVISOR;
int i;
for(i = 0; i < 16; i++) {
if (remainder & (uint32_t)1 << (23 - i))
remainder ^= divsor;
divsor >>= 1;
}
return remainder;
}
// return 1 if all OK, 0 if NACK
uint8_t htu_read_i2c(uint16_t *data){
uint8_t buf[3];
cntr = Tms;
while(I2C1->ISR & I2C_ISR_BUSY) if(Tms - cntr > 5) return 0; // check busy
cntr = Tms;
while(I2C1->CR2 & I2C_CR2_START) if(Tms - cntr > 5) return 0; // check start
// read three bytes
I2C1->CR2 = 3<<16 | HTU21_ADDR | 1 | I2C_CR2_AUTOEND | I2C_CR2_RD_WRN;
I2C1->CR2 |= I2C_CR2_START;
int i;
cntr = Tms;
for(i = 0; i < 3; ++i){
while(!(I2C1->ISR & I2C_ISR_RXNE)){ // wait for data
if(I2C1->ISR & I2C_ISR_NACKF){
I2C1->ICR |= I2C_ICR_NACKCF;
return 0;
}
if(Tms - cntr > 5) return 0;
}
buf[i] = I2C1->RXDR;
}
*data = (buf[0] << 8) | buf[1];
if(htu_check_crc(*data, buf[2])) return 1; // CRC error
return 1;
}
// return 0 if all OK
uint8_t htu_read_reg(uint8_t *data){
cntr = Tms;
while(I2C1->ISR & I2C_ISR_BUSY) if(Tms - cntr > 5) return 0; // check busy
cntr = Tms;
while(I2C1->CR2 & I2C_CR2_START) if(Tms - cntr > 5) return 0; // check start
I2C1->CR2 = 1<<16 | HTU21_ADDR; // 1 byte
I2C1->CR2 |= I2C_CR2_START;
cntr = Tms;
while(!(I2C1->ISR & I2C_ISR_TXIS)){ // ready to transmit
if(I2C1->ISR & I2C_ISR_NACKF){
I2C1->ICR |= I2C_ICR_NACKCF;
return 0;
}
if(Tms - cntr > 5) return 0;
}
I2C1->TXDR = HTU21_READ_REG;
cntr = Tms;
while(!(I2C1->ISR & I2C_ISR_TC)) if(Tms - cntr > 5) return 0; // wait transfer completion
I2C1->CR2 = 1<<16 | HTU21_ADDR | 1 | I2C_CR2_RD_WRN | I2C_CR2_AUTOEND; // receive, autoend
I2C1->CR2 |= I2C_CR2_START;
cntr = Tms;
while(!(I2C1->ISR & I2C_ISR_RXNE)){ // wait for data
if(I2C1->ISR & I2C_ISR_NACKF){
I2C1->ICR |= I2C_ICR_NACKCF;
return 0;
}
if(Tms - cntr > 5) return 0;
}
*data = I2C1->RXDR;
return 1;
}
uint8_t htu_write_reg(uint8_t data){
cntr = Tms;
while(I2C1->ISR & I2C_ISR_BUSY) if(Tms - cntr > 5) return 0; // check busy
cntr = Tms;
while(I2C1->CR2 & I2C_CR2_START) if(Tms - cntr > 5) return 0; // check start
I2C1->CR2 = 1<<16 | HTU21_ADDR; // 1 byte
I2C1->CR2 |= I2C_CR2_START;
cntr = Tms;
while(!(I2C1->ISR & I2C_ISR_TXIS)){ // ready to transmit
if(I2C1->ISR & I2C_ISR_NACKF){
I2C1->ICR |= I2C_ICR_NACKCF;
return 0;
}
if(Tms - cntr > 5) return 0;
}
I2C1->TXDR = HTU21_WRITE_REG;
cntr = Tms;
while(!(I2C1->ISR & I2C_ISR_TC)) if(Tms - cntr > 5) return 0; // wait transfer completion
I2C1->CR2 |= I2C_CR2_AUTOEND; // receive, autoend
I2C1->CR2 |= I2C_CR2_START;
cntr = Tms;
while(!(I2C1->ISR & I2C_ISR_TXIS)){ // ready to transmit
if(I2C1->ISR & I2C_ISR_NACKF){
I2C1->ICR |= I2C_ICR_NACKCF;
return 0;
}
if(Tms - cntr > 5) return 0;
}
I2C1->TXDR = data;
return 1;
}
//output in Cx10
int16_t convert_temperature(uint16_t in){
in = in & 0xFFFC;
uint32_t a = (uint32_t)in * 17572;
a >>= 16;
int16_t val = ((int16_t)a - 4685)/10;
return val;
}
//output in %x10
int16_t convert_humidity(uint16_t in){
in = in & 0xFFFC;
uint32_t a = (uint32_t)in * 1250;
a >>= 16;
int16_t val = (int16_t)a - 60;
return val;
}

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F0-nolib/htu21d_nucleo/i2c.h Normal file
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/*
* geany_encoding=koi8-r
* i2c.h
*
* Copyright 2017 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.
*
*/
#define HTU21_ADDR (0x40 << 1)
#define HTU21_READ_TEMP (0xF3)
#define HTU21_READ_HUMID (0xF5)
#define HTU21_READ_REG (0xE7)
#define HTU21_WRITE_REG (0xE6)
#define HTU21_SOFT_RESET (0xFE)
// user reg fields
#define HTU21_REG_VBAT (0x40)
#define HTU21_REG_D1 (0x80)
#define HTU21_REG_D0 (0x01)
#define HTU21_REG_HTR (0x04)
#define HTU21_REG_ODIS (0x02)
void i2c_setup();
int16_t convert_temperature(uint16_t in);
int16_t convert_humidity(uint16_t in);
uint8_t htu_write_reg(uint8_t data);
uint8_t htu_read_reg(uint8_t *data);
uint8_t htu_read_i2c(uint16_t *data);
uint8_t htu_write_i2c(uint8_t data);

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F0-nolib/htu21d_nucleo/ld/stm32f042k.ld Normal file
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/* Linker script for STM32F042x6, 32K flash, 6K RAM. */
/* Define memory regions. */
MEMORY
{
rom (rx) : ORIGIN = 0x08000000, LENGTH = 32K
ram (rwx) : ORIGIN = 0x20000000, LENGTH = 6K
}
/* Include the common ld script. */
INCLUDE stm32f0.ld

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F0-nolib/htu21d_nucleo/main.c Normal file
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/*
* main.c
*
* Copyright 2017 Edward V. Emelianoff <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 "stm32f0.h"
#include "usart.h"
#include "i2c.h"
volatile uint32_t Tms = 0;
/* Called when systick fires */
void sys_tick_handler(void){
++Tms;
}
static void gpio_setup(void){
// Set green led (PB3) as output
RCC->AHBENR |= RCC_AHBENR_GPIOBEN;
GPIOB->MODER = GPIO_MODER_MODER3_O;
}
void printi(int16_t val){
char buf[6], rbuf[5];
int l = 0, bpos = 0;
if(!val){
buf[0] = '0';
l = 1;
}else{
if(val < 0){
buf[0] = '-';
bpos = 1;
val = -val;
}
while(val){
rbuf[l++] = val % 10 + '0';
val /= 10;
}
int i;
bpos += l;
for(i = 0; i < l; ++i){
buf[--bpos] = rbuf[i];
}
}
while(ALL_OK != usart2_send_blocking(buf, l+bpos));
}
int main(void){
uint32_t lastT = 0;
int16_t L = 0;
int _1sec = 0, T_H = 0; // T_H - read t(1) or h(0)
uint32_t msctr = 0;
char *txt;
sysreset();
SysTick_Config(6000, 1);
gpio_setup();
usart2_setup();
i2c_setup();
while (1){
if(lastT > Tms || Tms - lastT > 499){
pin_toggle(GPIOB, 1<<3); // blink by onboard LED once per second
lastT = Tms;
}
if(usart2rx()){ // usart1 received data, store in in buffer
L = usart2_getline(&txt);
printi(L);
// do something with received data
}
if(L){ // text waits for sending
if(ALL_OK == usart2_send(txt, L)){
L = 0;
}
}
if(msctr != Tms){
msctr = Tms;
if(++_1sec >= 1000){ // once per 1 second
_1sec = 0;
// send H/T
uint8_t command = HTU21_READ_HUMID;
if(T_H) command = HTU21_READ_TEMP;
if(!htu_write_i2c(command))
while(ALL_OK != usart2_send_blocking("Error!\n", 7));
}
}
// poll I2C
uint16_t val = 0;
if(htu_read_i2c(&val)){ // got data
if(T_H){
while(ALL_OK != usart2_send_blocking("Temperature: ", 13));
int16_t t = convert_temperature(val);
printi(t);
while(ALL_OK != usart2_send_blocking("/10 degrC\n", 10));
}else{
while(ALL_OK != usart2_send_blocking("Humidity: ", 10));
int16_t h = convert_humidity(val);
printi(h);
while(ALL_OK != usart2_send_blocking("/10 %\n", 6));
}
T_H = !T_H;
}else{
if(val) // CRC error
while(ALL_OK != usart2_send_blocking("CRC error!\n", 11));
}
}
return 0;
}

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F0-nolib/htu21d_nucleo/usart.bin Executable file
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F0-nolib/htu21d_nucleo/usart.c Normal file
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/*us
* usart.c
*
* Copyright 2017 Edward V. Emelianoff <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 "stm32f0.h"
#include "usart.h"
#include <string.h>
extern volatile uint32_t Tms;
static int datalen[2] = {0,0}; // received data line length (including '\n')
int linerdy = 0, // received data ready
dlen = 0, // length of data (including '\n') in current buffer
bufovr = 0, // input buffer overfull
txrdy = 1 // transmission done
;
int rbufno = 0; // current rbuf number
static char rbuf[UARTBUFSZ][2], tbuf[UARTBUFSZ]; // receive & transmit buffers
static char *recvdata = NULL;
/**
* return length of received data (without trailing zero
*/
int usart2_getline(char **line){
if(bufovr){
bufovr = 0;
linerdy = 0;
return 0;
}
*line = recvdata;
linerdy = 0;
return dlen;
}
TXstatus usart2_send(const char *str, int len){
if(!txrdy) return LINE_BUSY;
if(len > UARTBUFSZ) return STR_TOO_LONG;
txrdy = 0;
memcpy(tbuf, str, len);
DMA1_Channel4->CCR &= ~DMA_CCR_EN;
DMA1_Channel4->CNDTR = len;
DMA1_Channel4->CCR |= DMA_CCR_EN; // start transmission
return ALL_OK;
}
TXstatus usart2_send_blocking(const char *str, int len){
if(!txrdy) return LINE_BUSY;
int i;
bufovr = 0;
for(i = 0; i < len; ++i){
USART2->TDR = *str++;
while(!(USART2->ISR & USART_ISR_TXE));
}
txrdy = 1;
return ALL_OK;
}
// Nucleo's USART2 connected to VCP proxy of st-link
void usart2_setup(){
// setup pins: PA2 (Tx - AF1), PA15 (Rx - AF1)
RCC->AHBENR |= RCC_AHBENR_GPIOAEN | RCC_AHBENR_DMAEN;
// AF mode (AF1)
GPIOA->MODER = (GPIOA->MODER & ~(GPIO_MODER_MODER2|GPIO_MODER_MODER15))\
| (GPIO_MODER_MODER2_1 | GPIO_MODER_MODER15_1);
GPIOA->AFR[0] = (GPIOA->AFR[0] &~GPIO_AFRH_AFRH2) | 1 << (2 * 4); // PA2
GPIOA->AFR[1] = (GPIOA->AFR[1] &~GPIO_AFRH_AFRH7) | 1 << (7 * 4); // PA15
// DMA: Tx - Ch4
DMA1_Channel4->CPAR = (uint32_t) &USART2->TDR; // periph
DMA1_Channel4->CMAR = (uint32_t) tbuf; // mem
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_5_IRQn, 3);
NVIC_EnableIRQ(DMA1_Channel4_5_IRQn);
NVIC_SetPriority(USART2_IRQn, 0);
// setup usart2
RCC->APB1ENR |= RCC_APB1ENR_USART2EN; // clock
// oversampling by16, 115200bps (fck=48mHz)
//USART2_BRR = 0x1a1; // 48000000 / 115200
USART2->BRR = 480000 / 1152;
USART2->CR3 = USART_CR3_DMAT; // enable DMA Tx
USART2->CR1 = USART_CR1_TE | USART_CR1_RE | USART_CR1_UE; // 1start,8data,nstop; enable Rx,Tx,USART
while(!(USART2->ISR & USART_ISR_TC)); // polling idle frame Transmission
USART2->ICR |= USART_ICR_TCCF; // clear TC flag
USART2->CR1 |= USART_CR1_RXNEIE;
NVIC_EnableIRQ(USART2_IRQn);
}
void dma1_channel4_5_isr(){
if(DMA1->ISR & DMA_ISR_TCIF4){ // Tx
DMA1->IFCR |= DMA_IFCR_CTCIF4; // clear TC flag
txrdy = 1;
}
}
void usart2_isr(){
#ifdef CHECK_TMOUT
static uint32_t tmout = 0;
#endif
if(USART2->ISR & USART_ISR_RXNE){ // RX not emty - receive next char
#ifdef CHECK_TMOUT
if(tmout && Tms >= tmout){ // set overflow flag
bufovr = 1;
datalen[rbufno] = 0;
}
tmout = Tms + TIMEOUT_MS;
if(!tmout) tmout = 1; // prevent 0
#endif
// read RDR clears flag
uint8_t rb = USART2->RDR;
if(datalen[rbufno] < UARTBUFSZ){ // put next char into buf
rbuf[rbufno][datalen[rbufno]++] = rb;
if(rb == '\n'){ // got newline - line ready
linerdy = 1;
dlen = datalen[rbufno];
recvdata = rbuf[rbufno];
// prepare other buffer
rbufno = !rbufno;
datalen[rbufno] = 0;
#ifdef CHECK_TMOUT
// clear timeout at line end
tmout = 0;
#endif
}
}else{ // buffer overrun
bufovr = 1;
datalen[rbufno] = 0;
#ifdef CHECK_TMOUT
tmout = 0;
#endif
}
}
}

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/*
* usart.h
*
* Copyright 2017 Edward V. Emelianoff <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 __USART_H__
#define __USART_H__
// input and output buffers size
#define UARTBUFSZ (64)
// timeout between data bytes
#ifndef TIMEOUT_MS
#define TIMEOUT_MS (1500)
#endif
typedef enum{
ALL_OK,
LINE_BUSY,
STR_TOO_LONG
} TXstatus;
#define usart2rx() (linerdy)
#define usart2ovr() (bufovr)
extern int linerdy, bufovr, txrdy;
void usart2_setup();
int usart2_getline(char **line);
TXstatus usart2_send(const char *str, int len);
TXstatus usart2_send_blocking(const char *str, int len);
#endif // __USART_H__