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stm32f030: PF0/PF1 as GPIO

Question asked by DeKoepi on Sep 6, 2014
Latest reply on Sep 6, 2014 by DeKoepi
Dear forum members,

I hope you can help solving a mystery. I stumbled upon these cute stm32f030f4 µCs and built minimalistic boards with it. No external oscillator used, thus pins PF0 and PF1 should be useable as GPIOs.

I tried several things already. Current state is explicitly disabling HSE, deinit the clock system and setting it up correctly:

// ---- Setup PLL for 48 MHz :) ----
RCC_PLLConfig(RCC_PLLSource_HSI, RCC_PLLMul_12);
// Flash: 1 WaitState for 24MHz < SysCLK < 48 MHz
// Set ADC clock to internal 14MHz HSI source
// and turn the PLL back on again
// set PLL as system clock source
// ---- End of Setup PLL for 48 MHz :) ----

It doesn't make a difference whether the HSE-Disable is before or after deinit. I also modified CMSIS/stm32f0xx.c -> SysCLKinit so HSE was disabled by all means, but that didn't help either.

Further pin setup:

    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOF, ENABLE);
    // LED: Configure PF0 and PF1 in output pushpull mode
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_Init(GPIOF, &GPIO_InitStructure);
// and in main loop:
    GPIOF->BRR = (GPIO_Pin_0);  // Set PF0 to GND
    uint32_t my_counter = 0;
    int step = 10;
    uint32_t border=10000;
    while (1) {
        my_counter += step;
        if ((my_counter == border) | (my_counter==0)) {
            step = -step;
        GPIOF->BSRR = GPIO_Pin_1;  // Set PF1 HIGH  (LED on)
        GPIOF->BRR = GPIO_Pin_1;  // Set PF1 to GND (LED off)

Setup for the pins as Alternative Function, AF0 or AF1, didn't make a difference.

I'm running out of ideas what else to do to get all 15 GPIOs working. Maybe someone already managed that and has a pointer to the solution.

Thanks for taking the time to read through all this! :)