Hello,
I figured out an issue with the code itself but I want to describe it here to get more clarification on what's really going on.
I used to have code that looks like this:
In file bsp_io.h:
typedef struct
{
GPIO_TypeDef *port; /*!< IO port */
uint32_t pin; /*!< IO pin */
uint32_t mode; /*!< IO mode - IN/OUT/AF */
uint32_t otype /*!< IO output type - PP/OD */
uint32_t af; /*!< IO alternate mode # */
uint32_t speed; /*!< IO speed - LO/MED/HI */
uint32_t pull; /*!< IO pull res. - UP/DOWN/NONE */
} bsp_io_handle_t;
In file bsp_usr_ctrl.c (where variables in all CAPS are #defined and their exact values are unimportant):
#include bsp_io.h
static bsp_io_handle_t io_handle;
void bsp_usr_ctrl_init(void)
{
io_handle.mode = BSP_IO_MODE_IN;
io_handle.pin = MENU_BTN_PIN | BACK_BTN_PIN;
io_handle.port = USR_BTNS_PORT;
io_handle.pull = BSP_IO_NOPULL;
io_handle.speed = BSP_IO_SPEED_LOW;
bsp_io_init(&io_handle); // Configures I/Os accordingly
}
void bsp_usr_ctrl_deinit(void)
{
bsp_io_deinit(&io_handle); // Return I/Os to reset state
}
And in my main.c I have something like this:
__NO_RETURN int main(void)
{
bsp_usr_ctrl_init();
// Some other code...
bsp_usr_ctrl_deinit();
// Other code...
}
And I've seen the io_handle structure, whose fields should have remained untouched since when it was initialized with bsp_usr_ctrl_init(), get reset mainly to 0's when bsp_usr_ctrl_deinit() is called. This raises an exception and stops the code to avoid writing values to any illegal memory locations. I've also seen this cause hard fault type exceptions which I haven't exactly been able to trace since I'm not sure what code was being executed when the hard fault(s) occurred.
I managed to fix these problems by allocating memory for io_handle with malloc() as follows:
#include bsp_io.h
#include <stdlib.h> // For malloc(), free()
static bsp_io_handle_t *io_handle;
void bsp_usr_ctrl_init(void)
{
io_handle = malloc(sizeof(bsp_io_handle_t));
io_handle->mode = BSP_IO_MODE_IN;
io_handle->pin = MENU_BTN_PIN | BACK_BTN_PIN;
io_handle->port = CAL_BTNS_PORT;
io_handle->pull = BSP_IO_NOPULL;
io_handle->speed = BSP_IO_SPEED_LOW;
bsp_io_init(io_handle);
}
void bsp_usr_ctrl_deinit(void)
{
bsp_io_deinit(io_handle);
free(io_handle);
}
OK, here's the thing I don't understand (and I don't know if this is an STM issue or just a vanilla C programming issue):
Since the structure was declared with "static" in the original code, why did that code allow the structure to be overwritten? BTW the original code was working without any issues on an STM32F3* family MCU. That's why I suspected that I may have set something up incorrectly in the memory specification in project settings. Like a stack vs. heap issue or something like that?
If anyone can shed any light on this it would be great!
