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systick blink

This commit is contained in:
olikraus 2017-04-05 06:04:25 +02:00
parent 791583ada2
commit a61498aa63
1 changed files with 27 additions and 2 deletions
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29
sys/arm/stm32l031x6/blink/main.c
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@ -1,22 +1,47 @@
// stm32flash -e 255 -w blink.hex -v /dev/ttyUSB0
#include "stm32l031xx.h"
volatile unsigned long SysTickCount = 0;
void __attribute__ ((interrupt, used)) SysTick_Handler(void)
{
SysTickCount++;
if ( SysTickCount & 1 )
GPIOA->BSRR = GPIO_BSRR_BS_13; /* atomic set PA13 */
else
GPIOA->BSRR = GPIO_BSRR_BR_13; /* atomic clr PA13 */
}
int main()
{
//RCC->CFGR &=
RCC->IOPENR |= RCC_IOPENR_IOPAEN; /* Enable clock for GPIO Port A */
__NOP();
RCC->IOPRSTR |= RCC_IOPRSTR_IOPARST; /* reset GPIO Port A */
__NOP();
GPIOA->MODER &= ~GPIO_MODER_MODE13; /* clear mode for PA13 */
GPIOA->MODER |= GPIO_MODER_MODE13_1; /* Output mode for PA13 */
GPIOA->MODER |= GPIO_MODER_MODE13_0; /* Output mode for PA13 */
GPIOA->OTYPER &= ~GPIO_OTYPER_OT_13; /* no Push/Pull for PA13 */
GPIOA->OSPEEDR &= ~GPIO_OSPEEDER_OSPEED13; /* low speed for PA13 */
GPIOA->PUPDR &= ~GPIO_PUPDR_PUPD13; /* no pullup/pulldown for PA13 */
//GPIOA->BSRR = GPIO_BSRR_BS_13; /* atomic set PA13 */
GPIOA->BSRR = GPIO_BSRR_BR_13; /* atomic clr PA13 */
//SysTick->LOAD = (SystemCoreClock/1000UL*(unsigned long)SYS_TICK_PERIOD_IN_MS) - 1;
SysTick->LOAD = 2000*500 - 1;
SysTick->VAL = 0;
SysTick->CTRL = 7; /* enable, generate interrupt (SysTick_Handler), do not divide by 2 */
for(;;)
;
}