fix: add full ITM initialization for STM32F4 SWD trace compatibility

All_source_codes/target/itm_send_data.c

@@ -1,31 +1,36 @@
+/* Defines for ITM */
+#define DEMCR_TRCENA         (1U << 24)
+#define DEMCR                *((volatile uint32_t*) 0xE000EDFCU)
+
+#define ITM_STIMULUS_PORT0   *((volatile uint32_t*) 0xE0000000)
+#define ITM_TRACE_ENABLE     *((volatile uint32_t*) 0xE0000E00)
+#define ITM_TRACE_EN_PORT0   (1U << 0)
+
+
+/**
+  * @brief  Initializes the ITM hardware for tracing.
+  * @brief  This function should be called ONCE from your main() function.
+  * @param  None
+  * @retval None
+  */
+void ITM_Init(void)
+{
+    DEMCR |= DEMCR_TRCENA;          // Enable TRCENA
+    ITM_TRACE_ENABLE |= ITM_TRACE_EN_PORT0; // Enable ITM stimulus port 0
+}
 
-/////////////////////////////////////////////////////////////////////////////////////////////////////////
-//					Implementation of printf like feature using ARM Cortex M3/M4/ ITM functionality
-//					This function will not work for ARM Cortex M0/M0+
-//					If you are using Cortex M0, then you can use semihosting feature of openOCD
-/////////////////////////////////////////////////////////////////////////////////////////////////////////
-
-
-//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 )
-
+/**
+  * @brief  Transmits a single character over ITM stimulus port 0.
+  * @param  ch: The character to transmit
+  * @retval None
+  */
 void ITM_SendChar(uint8_t ch)
 {
+    // Wait until ITM TxFIFO is ready (bit 0 is 1)
+    while (!(ITM_STIMULUS_PORT0 & 1));
 
-	//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;
+    // Write to ITM stimulus port 0
+    // Note: The port is 32-bit, but we only write a byte.
+    ITM_STIMULUS_PORT0 = (uint32_t)ch;
 }
 

All_source_codes/target/main.c

@@ -0,0 +1,22 @@
+//main.c
+#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
+
+// Add this prototype for the function in syscalls.c
+void ITM_Init(void);
+
+int main(void)
+{
+    ITM_Init(); // Initialize the ITM hardware
+    while(1){
+    /* Loop forever */
+    printf("Hello World\n"); 
+    }
+
+    for(;;);
+}
+

All_source_codes/target/syscalls.c

@@ -0,0 +1,199 @@
+//syscalls.c
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdio.h>
+#include <signal.h>
+#include <time.h>
+#include <sys/time.h>
+#include <sys/times.h>
+#include <stdint.h> // This include defines int8_t, uint8_t, uint32_t etc.
+
+/* Defines for ITM */
+#define DEMCR_TRCENA         (1U << 24)
+#define DEMCR                *((volatile uint32_t*) 0xE000EDFCU)
+
+#define ITM_STIMULUS_PORT0   *((volatile uint32_t*) 0xE0000000)
+#define ITM_TRACE_ENABLE     *((volatile uint32_t*) 0xE0000E00)
+#define ITM_TRACE_EN_PORT0   (1U << 0)
+
+
+/**
+  * @brief  Initializes the ITM hardware for tracing.
+  * @brief  This function should be called ONCE from your main() function.
+  * @param  None
+  * @retval None
+  */
+void ITM_Init(void)
+{
+    DEMCR |= DEMCR_TRCENA;          // Enable TRCENA
+    ITM_TRACE_ENABLE |= ITM_TRACE_EN_PORT0; // Enable ITM stimulus port 0
+}
+
+/**
+  * @brief  Transmits a single character over ITM stimulus port 0.
+  * @param  ch: The character to transmit
+  * @retval None
+  */
+void ITM_SendChar(uint8_t ch)
+{
+    // Wait until ITM TxFIFO is ready (bit 0 is 1)
+    while (!(ITM_STIMULUS_PORT0 & 1));
+
+    // Write to ITM stimulus port 0
+    // Note: The port is 32-bit, but we only write a byte.
+    ITM_STIMULUS_PORT0 = (uint32_t)ch;
+}
+
+
+/* Variables */
+extern int __io_putchar(int ch) __attribute__((weak));
+extern int __io_getchar(void) __attribute__((weak));
+
+
+char *__env[1] = { 0 };
+char **environ = __env;
+
+
+/* Functions */
+void initialise_monitor_handles()
+{
+}
+
+int _getpid(void)
+{
+  return 1;
+}
+
+int _kill(int pid, int sig)
+{
+  (void)pid;
+  (void)sig;
+  errno = EINVAL;
+  return -1;
+}
+
+void _exit (int status)
+{
+  _kill(status, -1);
+  while (1) {}    /* Make sure we hang here */
+}
+
+__attribute__((weak)) int _read(int file, char *ptr, int len)
+{
+  (void)file;
+  int DataIdx;
+
+  for (DataIdx = 0; DataIdx < len; DataIdx++)
+  {
+    *ptr++ = __io_getchar();
+  }
+
+  return len;
+}
+
+__attribute__((weak)) int _write(int file, char *ptr, int len)
+{
+  (void)file; // Suppress unused parameter warning
+  int DataIdx;
+
+  // ******************************************************************
+  // ** This is the function that routes printf to ITM_SendChar.
+  // **
+  // ** REMINDER: You must call ITM_Init() once in your main.c
+  // ** before using printf() for the first time.
+  // ******************************************************************
+
+  for (DataIdx = 0; DataIdx < len; DataIdx++)
+  {
+    // __io_putchar(*ptr++); // Default behavior
+    ITM_SendChar(*ptr++); // Redirect to ITM
+  }
+  return len;
+}
+
+int _close(int file)
+{
+  (void)file;
+  return -1;
+}
+
+
+int _fstat(int file, struct stat *st)
+{
+  (void)file;
+  st->st_mode = S_IFCHR; // Corrected: removed extra 'st->'
+  return 0;
+}
+
+int _isatty(int file)
+{
+  (void)file;
+  return 1;
+}
+
+int _lseek(int file, int ptr, int dir)
+{
+  (void)file;
+  (void)ptr;
+  (void)dir;
+  return 0;
+}
+
+int _open(char *path, int flags, ...)
+{
+  (void)path;
+  (void)flags;
+  /* Pretend like we always fail */
+  return -1;
+}
+
+int _wait(int *status)
+{
+  (void)status;
+  errno = ECHILD;
+  return -1;
+}
+
+int _unlink(char *name)
+{
+  (void)name;
+  errno = ENOENT;
+  return -1;
+}
+
+int _times(struct tms *buf)
+{
+  (void)buf;
+  return -1;
+}
+
+int _stat(char *file, struct stat *st)
+{
+  (void)file;
+  st->st_mode = S_IFCHR;
+  return 0;
+}
+
+int _link(char *old, char *new)
+{
+  (void)old;
+  (void)new;
+  errno = EMLINK;
+  return -1;
+}
+
+int _fork(void)
+{
+  errno = EAGAIN;
+  return -1;
+}
+
+int _execve(char *name, char **argv, char **env)
+{
+  (void)name;
+  (void)argv;
+  (void)env;
+  errno = ENOMEM;
+  return -1;
+}