Solved
Unable to use PC15 as GPIO input
Hello everyone,
I'm working on a project using an stm32f030rc. I need to use PC15 as a GPIO input but it appears I'm unable to.
I understand the couple PC14/PC15 is shared with the LFE oscillator, but of course I'm not using that function. Moreover, I am able to read the correct pin level on the PC14 GPIO. In the datasheed regarding my model the PC15 pin is marked as a I/O with OSC32_OUT as additional function: can it be used as input at all?
For reference, this is the C code I'm using to test the functionality; I'm using libopencm3 for initialization.
#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/gpio.h>
static void clock_setup(void)
{
rcc_clock_setup_in_hsi_out_48mhz();
/* Enable GPIOA, GPIOB, GPIOC clock. */
rcc_periph_clock_enable(RCC_GPIOA);
rcc_periph_clock_enable(RCC_GPIOB);
rcc_periph_clock_enable(RCC_GPIOC);
rcc_periph_clock_enable(RCC_DBGMCU);
/* Enable clocks for GPIO port B and C*/
gpio_mode_setup(GPIOA, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO5);
gpio_mode_setup(GPIOC, GPIO_MODE_INPUT, GPIO_PUPD_NONE, GPIO15);
gpio_mode_setup(GPIOC, GPIO_MODE_INPUT, GPIO_PUPD_NONE, GPIO14);
}
int main(void)
{
unsigned long long i = 0;
clock_setup();
/* Blink the LED (PA8) on the board with every transmitted byte. */
while (1)
{
gpio_toggle(GPIOA, GPIO5); /* LED on/off */
for (i = 0; i < 400000; i++) /* Wait a bit. */
__asm__("nop");
// This conditional is never entered
if (gpio_get(GPIOC, GPIO15) == 0) {
__asm__("nop");
__asm__("nop");
__asm__("nop");
}
// This one works
if (gpio_get(GPIOC, GPIO14) == 0) {
__asm__("nop");
__asm__("nop");
__asm__("nop");
}
}
return 0;
}