1 files changed, 85 insertions, 0 deletions
diff --git a/usart_irq/main.c b/usart_irq/main.c
new file mode 100644
index 0000000..c3e7966
--- /dev/null
+++ b/usart_irq/main.c
@@ -0,0 +1,85 @@
+
+
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/gpio.h>
+
+#include "usart.h"
+
+
+#define DELAY 1000000
+
+
+void clock_init(void);
+void gpio_init(void);
+void delay(void);
+int _write(int file, char *ptr, int len);
+
+
+USART usart3;
+
+
+int main(void)
+{
+	clock_init();
+	gpio_init();
+	usart_init(&usart3);
+
+	gpio_set(GPIOC, GPIO13);
+
+	char welcome[] = "Hallo Freunde!\r";
+	usart_write(&usart3, welcome);
+
+	uint8_t buff;
+
+	while(1){
+		if (usart_read_bytes(&usart3, &buff, 1)){
+			usart_write_bytes(&usart3, &buff, 1);
+		}
+	}
+
+	return 0;
+}
+
+
+void clock_init(void)
+{
+	rcc_periph_clock_enable(RCC_GPIOC);  // for PC13 blinking
+}
+
+
+void gpio_init(void)
+{
+	gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO13);
+	gpio_clear(GPIOC, GPIO13);
+}
+
+
+void delay(void)
+{
+	for (int i = 0; i < DELAY; i++) {
+		__asm__("nop");
+	}
+}
+
+
+int _write(int file, char *ptr, int len)
+{
+	int i;
+
+	if (file == STDOUT_FILENO || file == STDERR_FILENO) {
+		for (i = 0; i < len; i++) {
+			if (ptr[i] == '\n') {
+				uint8_t cr = (uint8_t)'\r';
+				usart_write_bytes(&usart3, &cr, 1);
+			}
+			usart_write_bytes(&usart3, (uint8_t *)&ptr[i], 1);
+		}
+		return i;
+	}
+	errno = EIO;
+	return -1;
+}