Hi everyone,
I am new to the embedded world and I currently have a STM32 Nucleo L4R5ZI board. I am trying to print "Hello World" to the SWV ITM Data Console through port 0. I am following the Fastbit tutorial on Udemy which uses a STM32F407VG board.
I created a empty project that doesn't use any HALs or generated code from the CubeMX software. I included the stdio.h header file and have the printf("Hello World\n"); in the main loop of main.c file:
#include <stdint.h>
#include <stdio.h>
#if !defined(__SOFT_FP__) && defined(__ARM_FP)
#warning "FPU is not initialized, but the project is compiling for an FPU. Please initialize the FPU before use."
#endif
int main(void)
{
printf("Hello World\n");
/* Loop forever */
for(;;);
}
In the syscalls.c files, I created a new function as stated below which I got from the tutorial:
//Debug Exception and Monitor Control Register base address
#define DEMCR *((volatile uint32_t*) 0xE000EDFCU )
/* ITM register addresses */
#define ITM_STIMULUS_PORT0 *((volatile uint32_t*) 0xE0000000 )
#define ITM_TRACE_EN *((volatile uint32_t*) 0xE0000E00 )
void ITM_SendChar(uint8_t ch)
{
//Enable TRCENA
DEMCR |= ( 1 << 24);
//enable stimulus port 0
ITM_TRACE_EN |= ( 1 << 0);
// read FIFO status in bit [0]:
while(!(ITM_STIMULUS_PORT0 & 1));
//Write to ITM stimulus port0
ITM_STIMULUS_PORT0 = ch;
}
I then changed my write function as well:
__attribute__((weak)) int _write(int file, char *ptr, int len)
{
(void)file;
int DataIdx;
for (DataIdx = 0; DataIdx < len; DataIdx++)
{
// __io_putchar(*ptr++);
ITM_SendChar(*ptr++);
}
return len;
}
I then created a debug configuration using the following settings:
I then open the debugger and have a SWV ITM Data Console with port 0 enabled and have the trace started. When I run the code, nothing appears on the console.
What could be the issue? I thought it was an issue with the registers, but I verified the ITM_STIMULUS_PORT0
and ITM_TRACE_EN registers. I couldn't find the address for the DEMCR register.
Any help with be greatly appreciated!
