You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
52 lines
1.6 KiB
52 lines
1.6 KiB
/* LED blink project for the STM32L031 */ |
|
|
|
#include "stm32l031xx.h" |
|
|
|
volatile unsigned long SysTickCount = 0; |
|
|
|
void __attribute__ ((interrupt, used)) SysTick_Handler(void) |
|
{ |
|
SysTickCount++; |
|
switch ( SysTickCount & 3 ) |
|
{ |
|
case 0: |
|
GPIOA->BSRR = GPIO_BSRR_BS_13; /* atomic set PA13 */ |
|
break; |
|
case 1: |
|
GPIOA->BSRR = GPIO_BSRR_BR_13; /* atomic clr PA13 */ |
|
break; |
|
case 2: |
|
GPIOA->BSRR = GPIO_BSRR_BS_14; /* atomic set PA13 */ |
|
break; |
|
case 3: |
|
GPIOA->BSRR = GPIO_BSRR_BR_14; /* atomic clr PA13 */ |
|
break; |
|
} |
|
} |
|
|
|
int main() |
|
{ |
|
RCC->IOPENR |= RCC_IOPENR_IOPAEN; /* Enable clock for GPIO Port A */ |
|
__NOP(); |
|
__NOP(); |
|
GPIOA->MODER &= ~GPIO_MODER_MODE13; /* clear 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_BR_13; /* atomic clr PA13 */ |
|
|
|
GPIOA->MODER &= ~GPIO_MODER_MODE14; /* clear mode for PA14 */ |
|
GPIOA->MODER |= GPIO_MODER_MODE14_0; /* Output mode for PA14 */ |
|
GPIOA->OTYPER &= ~GPIO_OTYPER_OT_14; /* no Push/Pull for PA14 */ |
|
GPIOA->OSPEEDR &= ~GPIO_OSPEEDER_OSPEED14; /* low speed for PA14 */ |
|
GPIOA->PUPDR &= ~GPIO_PUPDR_PUPD14; /* no pullup/pulldown for PA14 */ |
|
GPIOA->BSRR = GPIO_BSRR_BR_14; /* atomic clr PA14 */ |
|
|
|
SysTick->LOAD = 2000*500 - 1; |
|
SysTick->VAL = 0; |
|
SysTick->CTRL = 7; /* enable, generate interrupt (SysTick_Handler), do not divide by 2 */ |
|
|
|
for(;;) |
|
; |
|
}
|
|
|