mirror of
https://github.com/eddyem/stm32samples.git
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78 lines
2.3 KiB
C
78 lines
2.3 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 "stm32g0.h"
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// KEY (intpullup->0) - PC0
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// LED - PC7
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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){ // xms < 1864!!!
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static uint32_t curms = 0;
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if(curms == xms) return;
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// 9MHz - HCLK/8
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// this function also clears counter so it starts right away
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SysTick_Config(9000 * xms); // arg should be < 0xffffff, so ms should be < 1864
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curms = xms;
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}
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static void gpio_setup(void){
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RCC->IOPENR = RCC_IOPENR_GPIOCEN; // enable PC
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// set PC7 as opendrain output, PC0 is pullup input
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GPIOC->MODER = GPIO_MODER_MODER7_O;
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GPIOC->PUPDR = GPIO_PUPDR_PUPD0;
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GPIOC->OTYPER = GPIO_OTYPER_OT7;
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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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StartHSE();
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//StartHSI48();
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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(GPIOC, 1<<7)){ // key not pressed - 'sos'
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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(GPIOC, 1<<7);
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else pin_set(GPIOC, 1<<7);
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}else{ // key pressed - blink with period of 1s
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systick_setup(500);
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if(blink_ctr & 1) pin_clear(GPIOC, 1<<7);
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else pin_set(GPIOC, 1<<7);
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}
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}
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}
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