Posted on September 20, 2012 at 01:42
After figuring out how to configure ARM GCC and Eclipse, I wrote the shortest demo program I could come up with. My program is supposed to light one LED when the user button is pressed, and the other LED when the button is not pressed.
You can probably figure that since I'm posting here, my code isn't working. Neither LED lights up. I'm probably missing something very simple but I can't figure it out. My code is below; I simplified it as much as possible. I've verified in the debugger that I'm hitting one of the GREEN_LED_PORT->BSRR = lines when the button is pressed, and the other when the button is not pressed, yet neither LED illuminates.
Any assistance would be greatly appreciated.
/* Includes ------------------------------------------------------------------*/
#include ''stm32f0xx.h''
/* Private define ------------------------------------------------------------*/
#define GREEN_LED_PIN GPIO_Pin_9
#define GREEN_LED_PORT GPIOC
#define BLUE_LED_PIN GPIO_Pin_8
#define BLUE_LED_PORT GPIOC
#define USER_BUTTON_PIN GPIO_Pin_0
#define USER_BUTTON_PORT GPIOA
#define GREEN_LED_PERIPH_CLOCK RCC_AHBPeriph_GPIOC
#define BLUE_LED_PERIPH_CLOCK RCC_AHBPeriph_GPIOC
#define USER_BUTTON_PERIPH_CLOCK RCC_AHBPeriph_GPIOA
#define USER_BUTTON_IS_PRESSED (USER_BUTTON_PORT->IDR & USER_BUTTON_PIN)
int
main(
void
)
{
//Set up the pins for the LEDs and user button
GPIO_InitTypeDef GPIOInit;
GPIOInit.GPIO_Mode = GPIO_Mode_OUT;
GPIOInit.GPIO_OType = GPIO_OType_PP;
GPIOInit.GPIO_Pin = GREEN_LED_PIN;
GPIOInit.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIOInit.GPIO_Speed = GPIO_Speed_Level_3;
GPIO_Init(GREEN_LED_PORT, &GPIOInit);
GPIOInit.GPIO_Pin = BLUE_LED_PIN;
GPIO_Init(BLUE_LED_PORT, &GPIOInit);
GPIOInit.GPIO_Mode = GPIO_Mode_IN;
GPIOInit.GPIO_Pin = USER_BUTTON_PIN;
GPIO_Init(USER_BUTTON_PORT, &GPIOInit);
//enable clocking to the GPIO ports
RCC_AHBPeriphClockCmd(GREEN_LED_PERIPH_CLOCK, ENABLE);
RCC_AHBPeriphClockCmd(BLUE_LED_PERIPH_CLOCK, ENABLE);
RCC_AHBPeriphClockCmd(USER_BUTTON_PERIPH_CLOCK, ENABLE);
//loop forever
while
(1)
{
if
(USER_BUTTON_IS_PRESSED)
{
GREEN_LED_PORT->BSRR = (GREEN_LED_PIN << 16) + BLUE_LED_PIN;
}
else
{
GREEN_LED_PORT->BSRR = (GREEN_LED_PIN << 16) + BLUE_LED_PIN;
}
}
}
