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docs/GD32F1x0_Firmware_Library_v3.1.0/Examples/USART/Printf/main.c

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+/*!
+    \file  main.c
+    \brief USART printf
+*/
+
+/*
+    Copyright (C) 2017 GigaDevice
+
+    2014-12-26, V1.0.0, platform GD32F1x0(x=3,5)
+    2016-01-15, V2.0.0, platform GD32F1x0(x=3,5,7,9)
+    2016-04-30, V3.0.0, firmware update for GD32F1x0(x=3,5,7,9)
+    2017-06-19, V3.1.0, firmware update for GD32F1x0(x=3,5,7,9)
+*/
+
+#include "gd32f1x0.h"
+#include <stdio.h>
+#include "gd32f1x0_eval.h"
+
+/*!
+    \brief      main function
+    \param[in]  none
+    \param[out] none
+    \retval     none
+*/
+int main(void)
+{
+    gd_eval_com_init(EVAL_COM1);
+    
+    printf("a usart transmit test example!");
+    while (1);
+}
+
+/* retarget the C library printf function to the USART */
+int fputc(int ch, FILE *f)
+{
+    usart_data_transmit(EVAL_COM1, (uint8_t)ch);
+    while(RESET == usart_flag_get(EVAL_COM1, USART_FLAG_TBE));
+    return ch;
+}