mirror of
https://github.com/eddyem/stm32samples.git
synced 2025-12-06 10:45:11 +03:00
115 lines
3.0 KiB
C
115 lines
3.0 KiB
C
/*
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* main.c
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*
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* Copyright 2017 Edward V. Emelianoff <eddy@sao.ru, 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 2 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, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*/
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#include "stm32f0.h"
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#include "usart.h"
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static uint32_t stk_ctr = 0;
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/* Called when systick fires */
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void sys_tick_handler(void){
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pin_toggle(GPIOB, GPIO3);
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++stk_ctr;
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}
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/*
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* Set up timer to fire every x milliseconds
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* This is a unusual usage of systick, be very careful with the 24bit range
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* of the systick counter! You can range from 1 to 2796ms with this.
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*/
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static void systick_setup(int xms){
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static int curms = 0;
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if(curms == xms) return;
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// 6MHz
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systick_set_clocksource(STK_CSR_CLKSOURCE_EXT);
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/* clear counter so it starts right away */
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STK_CVR = 0;
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systick_set_reload(6000 * xms);
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systick_counter_enable();
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systick_interrupt_enable();
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curms = xms;
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}
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/* set STM32 to clock by 48MHz from HSI oscillator */
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static void clock_setup(void){
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rcc_clock_setup_in_hsi_out_48mhz();
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//rcc_clock_setup_in_hse_8mhz_out_48mhz();
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/* Enable clocks to the GPIO subsystems (A&B) */
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RCC_AHBENR = RCC_AHBENR_GPIOAEN | RCC_AHBENR_GPIOBEN;
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}
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static void gpio_setup(void){
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// Set green led (PB3) as output
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gpio_mode_setup(GPIOB, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO3);
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}
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/**
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* reverce line
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*/
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char *rline(char *in, int L){
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static char out[UARTBUFSZ];
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if(L > UARTBUFSZ - 1) return in;
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char *optr = out, *iptr = &in[L-1];
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for(; L > 0; --L) *optr++ = *iptr--;
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*optr = '\n';
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return out;
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}
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int main(void){
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clock_setup();
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gpio_setup();
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usart2_setup();
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systick_setup(500); // 1Hz in normal mode
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const char dummy[] = "dummy text\n", err[] = "Error!\n";
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char *txt;
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int L = 0, dummyctr = 0;
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uint32_t ostctr = 0;
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while (1){
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if(L){ // there's something to send
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if(ALL_OK == usart2_send(txt, L)){
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L = 0;
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}else
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usart2_send_blocking(err, sizeof(err));
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}else if(ostctr != stk_ctr){
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ostctr = stk_ctr;
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if(++dummyctr > 10){ // once per 5 seconds
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dummyctr = 0;
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usart2_send(dummy, sizeof(dummy));
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}
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}
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if(usart2rx()){ // data received
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L = usart2_getline(&txt);
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if(L){
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txt = rline(txt, L);
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++L; // for trailing '\n'
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}
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}
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}
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return 0;
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}
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