Yet another blink a led question

[qwer.asdf]

Posted on March 12, 2017 at 16:56

I'm sorry in advance for such a stupid question, yet i can't find my error.

I have some chinese nameless 'stm32f103c8t6 system board' with F103C8T6 on board. I also use Coocoox IDE and ST-Link v2 programmer. The following code should blink a led, which is pulled up through 1k resistor. Also pin A1 is giving me only ~1.830 Volts when set to HIGH; however, when i set A1 to LOW it still shows ~1.830 Volts. Other pins are showing zero results. Did i get shady MC or am i missing something?

Also, i don't have oscilloscope, so i can't check what is going on with MCO pin, yet i get ~20-30 mVolts, which is not above ground level.

void InitGPIO()

{    RCC-> APB2ENR |= RCC_APB2ENR_AFIOEN;    RCC-> APB2ENR |= RCC_APB2ENR_IOPAEN;    GPIOA-> CRL &= ~GPIO_CRL_MODE1; // push-pull output    GPIOA-> CRL &= ~GPIO_CRL_CNF1; // led init on pin a1    GPIOA-> CRL |= GPIO_CRL_MODE1_1; // 2mhz output    GPIOA-> BSRR |= GPIO_BSRR_BR1; // rst a1 led pin    GPIOA-> CRL &= ~GPIO_CRL_MODE2; // push-pull output    GPIOA-> CRL &= ~GPIO_CRL_CNF2; // pin a2    GPIOA-> CRL |= GPIO_CRL_MODE2_0; // 10mhz output    GPIOA-> BSRR |= GPIO_BSRR_BS2; // set a2 pin

   GPIOA-> CRH &= ~GPIO_CRH_MODE8;

   GPIOA-> CRH &= ~GPIO_CRH_CNF8;    GPIOA-> CRH |= GPIO_CRH_CNF8_1; // af push pull output    GPIOA-> CRH |= (GPIO_CRH_MODE8_1                            | GPIO_CRH_MODE8_0); // 50mhz output

   // RCC-> CFGR |= RCC_CFGR_MCO_HSE; // hse clk on mco pin

   // RCC-> CFGR |= RCC_CFGR_MCO_PLL; // pll clk on mco pin    RCC-> CFGR |= RCC_CFGR_MCO_SYSCLK;// sysclk on mco pin}

int main(void)

{    InitGPIO();; while(1) {}  return 1;}

[S.Ma]

Posted on March 12, 2017 at 17:09

If you are using a debugger, show the HW register and manually edit them. No SW needed to toggle or read a pin level directly by hand. Read the schematic of the board and make sure the pin is the correct one as push pull setting. Check also the memory content such as the Chip ID 96 bit signature content.

[gbm]

Posted on March 12, 2017 at 18:41

1. LED is on PC13, you are trying to program PA.

2. Don't use |= when writing to BSRR registers, = is enough

[qwer.asdf · Accepted solution]

Posted on March 15, 2017 at 14:47

Well, totally my fault here. I should have checked all the reset functions and other ticks in program. If someone would ever fall into such an easy trap, here's the answer for Keil:

Options for Target > Debug > Debugger Settings > Flash Download > 'Reset and Run'.

Thanks for your time, folks.