mirror of
https://github.com/eddyem/stm32samples.git
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107 lines
3.4 KiB
C
107 lines
3.4 KiB
C
/*
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* This file is part of the F303usart project.
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* Copyright 2021 Edward V. Emelianov <edward.emelianoff@gmail.com>.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "stm32f3.h"
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#include "hardware.h"
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#include "usart.h"
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#include <string.h>
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static volatile int idatalen = 0; // received data line length (including '\n')
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volatile int linerdy = 0, // received data ready
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dlen = 0, // length of data (including '\n') in current buffer
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bufovr = 0; // input buffer overfull
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static volatile int rbufno = 0; // current rbuf number
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static char rbuf[2][UARTBUFSZ]; // receive buffers
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static volatile char *recvdata = NULL;
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/**
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* return length of received data (without trailing zero)
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*/
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int usart_getline(char **line){
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if(bufovr){
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bufovr = 0;
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linerdy = 0;
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return 0;
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}
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if(!linerdy) return 0;
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*line = (char*)recvdata;
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linerdy = 0;
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return dlen;
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}
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void usart_putchar(const char ch){
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while(!(USART1->ISR & USART_ISR_TXE));
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USART1->TDR = ch;
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}
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void usart_sendn(const char *str, int L){
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if(!str) return;
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for(int i = 0; i < L; ++i){
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usart_putchar(str[i]);
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}
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}
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void usart_send(const char *str){
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if(!str) return;
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int L = 0;
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const char *ptr = str;
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while(*ptr++) ++L;
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usart_sendn(str, L);
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}
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void usart_setup(){
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// USART1: Rx - PA10 (AF7), Tx - PA9 (AF7)
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// setup pins:
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GPIOA->MODER = (GPIOA->MODER & ~(GPIO_MODER_MODER9 | GPIO_MODER_MODER10)) |
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GPIO_MODER_MODER9_AF | GPIO_MODER_MODER10_AF;
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GPIOA->AFR[1] = (GPIOA->AFR[1] & ~(GPIO_AFRH_AFRH1 | GPIO_AFRH_AFRH2)) |
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7 << (1 * 4) | 7 << (2 * 4); // PA9, PA10
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// clock
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RCC->APB2ENR |= RCC_APB2ENR_USART1EN;
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USART1->ICR = 0xffffffff; // clear all flags
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USART1->BRR = 720000 / 1152;
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USART1->CR1 = USART_CR1_TE | USART_CR1_RE | USART_CR1_UE | USART_CR1_RXNEIE; // 1start,8data,nstop; enable Rx,Tx,USART
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uint32_t tmout = 16000000;
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while(!(USART1->ISR & USART_ISR_TC)){if(--tmout == 0) break;} // polling idle frame Transmission
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USART1->ICR = 0xffffffff; // clear all flags again
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NVIC_SetPriority(USART1_IRQn, 0);
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NVIC_EnableIRQ(USART1_IRQn);
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}
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void usart1_exti25_isr(){
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if(USART1->ISR & USART_ISR_RXNE){ // RX not emty - receive next char
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// read RDR clears flag
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uint8_t rb = USART1->RDR;
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if(idatalen < UARTBUFSZ){ // put next char into buf
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rbuf[rbufno][idatalen++] = rb;
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if(rb == '\n'){ // got newline - line ready
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linerdy = 1;
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dlen = idatalen;
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recvdata = rbuf[rbufno];
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recvdata[dlen-1] = 0;
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// prepare other buffer
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rbufno = !rbufno;
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idatalen = 0;
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}
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}else{ // buffer overrun
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bufovr = 1;
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idatalen = 0;
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}
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}
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}
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