STM32L_Discovery Blinking LEDS

[chuck_moore]

Posted on August 21, 2013 at 09:12

I have an STM32L-Discovery Board, I found this program compiled it and loaded it on my board but nothing happens.  What am I miising..  Thanks in Advanced. 

CM.GPIO_InitTypeDef (GPIO_InitStructure); int main() { GPIO_InitTypeDef ledInit; long i = 0;  // enable the GPIOB peripheralRCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE);RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6; // GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //  push-pull output GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz; GPIO_Init (GPIOB, & GPIO_InitStructure); // B port GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7; //GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //  push-pull output GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz; GPIO_Init (GPIOB, & GPIO_InitStructure); // B port    // configure pins 6 and 7 as GPIO output ledInit.GPIO_Pin = GPIO_Pin_7 | GPIO_Pin_6; ledInit.GPIO_Mode = GPIO_Mode_OUT;  // initialize the peripheral GPIO_Init(GPIOB, &ledInit);   // turn pins 6 and 7 on GPIO_SetBits(GPIOB, GPIO_Pin_7 | GPIO_Pin_6);  // loop forever for (;;) {           // toggle pins 6 and 7               GPIOB->BSRRL = GPIO_Pin_7;         GPIOB->BSRRH = GPIO_Pin_7;       GPIOB->BSRRL = GPIO_Pin_6;           GPIOB->BSRRH = GPIO_Pin_6; // waste time        for (i=0; i<25000; i++);      return 0;       }

[waclawek.jan]

Posted on August 21, 2013 at 09:30

In fact, the LED blink, but you can't see it.

This GPIOB->BSRRL = GPIO_Pin_7;          GPIOB->BSRRH = GPIO_Pin_7; sets then resets PB.7 in rapid succession, producing a very short pulse on it. The same in the following two lines for PB.6. You won't see the LED to blink for a fraction of microsecond. (Also, get rid of the second initialization of the GPIO) JW

[ran2]

Posted on August 21, 2013 at 17:04

Hi, Jan is right.

Try this: GPIOB->BSRRL = GPIO_Pin_7;        for (i=0; i<25000; i++);         GPIOB->BSRRH = GPIO_Pin_7;GPIOB->BSRRL = GPIO_Pin_6;                 for (i=0; i<25000; i++);                GPIOB->BSRRH = GPIO_Pin_6;

[chuck_moore]

Posted on August 21, 2013 at 19:44

You guys Rock :)...  This works for the STM32L-Discovery Boards compiled with Keil..

Not sure why this isn't in the SDK Project files...  Again many thanks for you quick response.Chuck

[Tesla DeLorean]

Posted on August 21, 2013 at 23:51

I'd recommend looking at both the L1 Discovery examples, and those in the L1 Firmware Library. While the latter is targeting the EVAL series boards, it is still useful.

See also \Keil\ARM\Boards\ST\STM32L-Discovery\Blinky\Blinky.c and examples posted to the forum.