1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
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;
}
|
