mirror of
https://github.com/eddyem/stm32samples.git
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88 lines
2.6 KiB
C
88 lines
2.6 KiB
C
/*
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* systick_blink.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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static volatile uint32_t blink_ctr = 0;
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/* Called when systick fires */
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void sys_tick_handler(void){
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++blink_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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*/
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static void systick_setup(uint32_t xms){
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static uint32_t curms = 0;
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if(curms == xms) return;
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// 6MHz - HCLK/8 (due to HPRE=1 HCLK=SYSCLK)
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// this function also clears counter so it starts right away
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SysTick_Config(6000 * xms, 1);
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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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//StartHSE(RCC_CR_CSSON | RCC_CR_HSEBYP);
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//}
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static void gpio_setup(void){
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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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/* Set green led (PB3) as output */
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GPIOB->MODER = GPIO_MODER_MODER3_O;
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// gpio_mode_setup(GPIOB, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO3);
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/* D2 - PA12 - switch blink rate (pullup input) */
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GPIOA->PUPDR = GPIO_PUPDR_PUPDR12_0;
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//gpio_mode_setup(GPIOA, GPIO_MODE_INPUT, GPIO_PUPD_PULLUP, GPIO12);
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}
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static const uint32_t L[] = {125,100,125,100,125,200, 350,100,350,100,350,200, 125,100,125,100,125, 1000};
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int main(void){
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sysreset();
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// set divider by 8
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SysTick->CTRL &= ~SysTick_CTRL_CLKSOURCE_Msk;
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//StartHSE();
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//StartHSI48();
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// clock_setup();
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gpio_setup();
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/* 500ms ticks => 1000ms period => 1Hz blinks */
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systick_setup(100);
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/* Do nothing in main loop */
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while (1){
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if(pin_read(GPIOA, 1<<12)){
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uint32_t T = blink_ctr % 18;
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systick_setup(L[T]);
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if(T & 1) pin_clear(GPIOB, 1<<3);
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else pin_set(GPIOB, 1<<3);
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}else{
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systick_setup(2000);
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if(blink_ctr & 1) pin_clear(GPIOB, 1<<3);
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else pin_set(GPIOB, 1<<3);
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}
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}
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}
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