mirror of
https://github.com/eddyem/stm32samples.git
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116 lines
3.7 KiB
Plaintext
116 lines
3.7 KiB
Plaintext
/*
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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 "stm32f1.h"
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static volatile uint8_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);
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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->APB2ENR |= RCC_APB2ENR_IOPBEN | RCC_APB2ENR_IOPCEN;
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/* Set leds (PB8/PB9) as opendrain output */
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GPIOB->CRH = CRH(8, CNF_ODOUTPUT|MODE_SLOW) | CRH(9, CNF_ODOUTPUT|MODE_SLOW);
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/* Set buttons (PC0/1) as inputs with weak pullups */
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GPIOC->ODR = 3; // pullups for PC0/1
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GPIOC->CRL = CRL(0, CNF_PUDINPUT|MODE_INPUT) | CRL(1, CNF_PUDINPUT|MODE_INPUT);
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}
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static const uint16_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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// AFIO->MAPR = AFIO_MAPR_SWJ_CFG_DISABLE; // turn off jtag and swim
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// StartHSE();
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RCC->CFGR &= ~RCC_CFGR_SW; // Change System Clock to HSI
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while ((RCC->CFGR & RCC_CFGR_SWS) != 0x00) {
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__NOP();
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};
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RCC->CR &= ~RCC_CR_PLLON; // Disable Pll
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while ((RCC->CR & RCC_CR_PLLON)) {
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__NOP();
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};
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RCC->CFGR &= ~0x3C0000;
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RCC->CFGR |= RCC_CFGR_PLLMULL4; // Set Pll Mul to 4
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RCC->CFGR |= RCC_CFGR_USBPRE;
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RCC->CFGR |= RCC_CFGR_PLLSRC;
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RCC->CR |= RCC_CR_PLLON;
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while (!(RCC->CR & RCC_CR_PLLON)) {
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__NOP();
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};
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RCC->CFGR |= RCC_CFGR_SW_1; // Change System Clock to PLL
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while ((RCC->CFGR & RCC_CFGR_SWS) != RCC_CFGR_SWS_1) {
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__NOP();
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};
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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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uint8_t oldctr = blink_ctr+1;
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pin_clear(GPIOB, 1<<8);
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pin_clear(GPIOB, 1<<9);
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for(int i = 0; i < 1000000; ++i) nop();
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/* Do nothing in main loop */
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while (1){
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if(pin_read(GPIOC, 1) && pin_read(GPIOC, 2)){ // no buttons present - morze @ LED1 (PB9)
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if(oldctr != blink_ctr){
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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_set(GPIOB, 1<<9);
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else pin_clear(GPIOB, 1<<9);
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oldctr = blink_ctr;
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}
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}else{ // button pressed: turn ON given LED
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if(pin_read(GPIOC, 1)){ // PC0 pressed (button S2)
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pin_clear(GPIOB, 1<<8);
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}else pin_set(GPIOB, 1<<8);
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if(pin_read(GPIOC, 2)){ // PC1 pressed (button S3)
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pin_clear(GPIOB, 1<<9);
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}else pin_set(GPIOB, 1<<8);
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}
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}
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}
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