feat: usart retarget

Core/Inc/retarget.h

@@ -0,0 +1,22 @@
+#ifndef _RETARGET_H__
+#define _RETARGET_H__
+
+#include "stm32f1xx_hal.h"
+#include <sys/stat.h>
+#include <stdio.h>
+
+void RetargetInit(UART_HandleTypeDef *huart);
+
+int _isatty(int fd);
+
+int _write(int fd, char *ptr, int len);
+
+int _close(int fd);
+
+int _lseek(int fd, int ptr, int dir);
+
+int _read(int fd, char *ptr, int len);
+
+int _fstat(int fd, struct stat *st);
+
+#endif //#ifndef _RETARGET_H__

Core/Src/main.c

@@ -27,6 +27,7 @@
 /* USER CODE BEGIN Includes */
 #include <stdio.h>
 
+#include "retarget.h"
 #include "oled.h"
 #include "rc522.h"
 /* USER CODE END Includes */
@@ -119,13 +120,19 @@ int main(void)
   MX_USART1_UART_Init();
   MX_SPI1_Init();
   /* USER CODE BEGIN 2 */
+  // Retarget uart
+  RetargetInit(&huart1);
+
+  // Init RC522
   MFRC_Init();
   PCD_Reset();
 
+  // Init OLED
   OLED_Init();
   OLED_Clear();
 
   OLED_ShowString(0,0,"Card scan...",12);
+  printf("startup\n");
   /* USER CODE END 2 */
 
   /* Infinite loop */

Core/Src/retarget.c

@@ -0,0 +1,98 @@
+#include <_ansi.h>
+#include <_syslist.h>
+#include <errno.h>
+#include <sys/time.h>
+#include <sys/times.h>
+#include <retarget.h>
+#include <stdint.h>
+
+#if !defined(OS_USE_SEMIHOSTING)
+
+#define STDIN_FILENO  0
+#define STDOUT_FILENO 1
+#define STDERR_FILENO 2
+
+UART_HandleTypeDef *gHuart;
+
+void RetargetInit(UART_HandleTypeDef *huart)
+{
+    gHuart = huart;
+    
+        /* Disable I/O buffering for STDOUT stream, so that
+         * chars are sent out as soon as they are printed. */
+        setvbuf(stdout, NULL, _IONBF, 0);
+}
+
+int _isatty(int fd)
+{
+    if (fd >= STDIN_FILENO && fd <= STDERR_FILENO)
+        return 1;
+    
+        errno = EBADF;
+    return 0;
+}
+
+int _write(int fd, char *ptr, int len)
+{
+    HAL_StatusTypeDef hstatus;
+    
+        if (fd == STDOUT_FILENO || fd == STDERR_FILENO)
+        {
+            hstatus = HAL_UART_Transmit(gHuart, (uint8_t *) ptr, len, HAL_MAX_DELAY);
+            if (hstatus == HAL_OK)
+                return len;
+            else
+                return EIO;
+        }
+    errno = EBADF;
+    return -1;
+}
+
+int _close(int fd)
+{
+    if (fd >= STDIN_FILENO && fd <= STDERR_FILENO)
+        return 0;
+    
+        errno = EBADF;
+    return -1;
+}
+
+int _lseek(int fd, int ptr, int dir)
+{
+    (void) fd;
+    (void) ptr;
+    (void) dir;
+    
+        errno = EBADF;
+    return -1;
+}
+
+int _read(int fd, char *ptr, int len)
+{
+    HAL_StatusTypeDef hstatus;
+    
+        if (fd == STDIN_FILENO)
+        {
+            hstatus = HAL_UART_Receive(gHuart, (uint8_t *) ptr, 1, HAL_MAX_DELAY);
+            if (hstatus == HAL_OK)
+                return 1;
+            else
+                return EIO;
+        }
+    errno = EBADF;
+    return -1;
+}
+
+int _fstat(int fd, struct stat *st)
+{
+    if (fd >= STDIN_FILENO && fd <= STDERR_FILENO)
+    {
+        st->st_mode = S_IFCHR;
+        return 0;
+    }
+    
+        errno = EBADF;
+    return 0;
+}
+
+#endif //#if !defined(OS_USE_SEMIHOSTING)

Core/Src/syscalls.c

@@ -89,33 +89,33 @@ __attribute__((weak)) int _write(int file, char *ptr, int len)
   return len;
 }
 
-int _close(int file)
-{
-  (void)file;
-  return -1;
-}
-
-
-int _fstat(int file, struct stat *st)
-{
-  (void)file;
-  st->st_mode = S_IFCHR;
-  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 _close(int file)
+// {
+//   (void)file;
+//   return -1;
+// }
+//
+//
+// int _fstat(int file, struct stat *st)
+// {
+//   (void)file;
+//   st->st_mode = S_IFCHR;
+//   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, ...)
 {