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34 lines
1018 B
34 lines
1018 B
/* LED blink project for the STM32L031 */ |
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#include "stm32l031xx.h" |
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volatile unsigned long SysTickCount = 0; |
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void __attribute__ ((interrupt, used)) SysTick_Handler(void) |
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{ |
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SysTickCount++; |
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if ( SysTickCount & 1 ) |
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GPIOA->BSRR = GPIO_BSRR_BS_13; /* atomic set PA13 */ |
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else |
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GPIOA->BSRR = GPIO_BSRR_BR_13; /* atomic clr PA13 */ |
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} |
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int main() |
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{ |
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RCC->IOPENR |= RCC_IOPENR_IOPAEN; /* Enable clock for GPIO Port A */ |
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__NOP(); |
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__NOP(); |
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GPIOA->MODER &= ~GPIO_MODER_MODE13; /* clear mode for PA13 */ |
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GPIOA->MODER |= GPIO_MODER_MODE13_0; /* Output mode for PA13 */ |
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GPIOA->OTYPER &= ~GPIO_OTYPER_OT_13; /* no Push/Pull for PA13 */ |
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GPIOA->OSPEEDR &= ~GPIO_OSPEEDER_OSPEED13; /* low speed for PA13 */ |
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GPIOA->PUPDR &= ~GPIO_PUPDR_PUPD13; /* no pullup/pulldown for PA13 */ |
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GPIOA->BSRR = GPIO_BSRR_BR_13; /* atomic clr PA13 */ |
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SysTick->LOAD = 2000*500 - 1; |
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SysTick->VAL = 0; |
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SysTick->CTRL = 7; /* enable, generate interrupt (SysTick_Handler), do not divide by 2 */ |
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for(;;) |
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; |
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}
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