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
86
87
88
|
#include "project.h"
#define BUFFER_SIZE 512
ring_t usart_rx_ring;
static uint8_t usart_rx_ring_buf[BUFFER_SIZE];
ring_t usart_tx_ring;
static uint8_t usart_tx_ring_buf[BUFFER_SIZE];
void
usart1_isr (void)
{
uint8_t data;
/* Check if we were called because of RXNE. */
if (((USART_CR1 (USART1) & USART_CR1_RXNEIE) != 0) &&
((USART_SR (USART1) & USART_SR_RXNE) != 0)) {
/* Retrieve the data from the peripheral. */
data = usart_recv (USART1);
ring_write_byte (&usart_rx_ring, data);
}
/* Check if we were called because of TXE. */
if (((USART_CR1 (USART1) & USART_CR1_TXEIE) != 0) &&
((USART_SR (USART1) & USART_SR_TXE) != 0)) {
if (ring_read_byte (&usart_tx_ring, &data)) {
/*No more data, Disable the TXE interrupt, it's no longer needed. */
USART_CR1 (USART1) &= ~USART_CR1_TXEIE;
} else
usart_send (USART1, data);
}
}
void usart_kick (void)
{
if (!ring_empty (&usart_tx_ring))
USART_CR1 (USART1) |= USART_CR1_TXEIE;
}
int
_write (int file, char *ptr, int len)
{
int ret;
if (file == 1) {
ret = ring_write (&usart_tx_ring, (uint8_t *) ptr, len);
usart_kick();
ring_write (&cdcacm_tx_ring, (uint8_t *) ptr, len);
if (ret < 0)
ret = -ret;
return ret;
}
errno = EIO;
return -1;
}
void
usart_init (void)
{
ring_init (&usart_rx_ring, usart_rx_ring_buf, sizeof (usart_rx_ring_buf));
ring_init (&usart_tx_ring, usart_tx_ring_buf, sizeof (usart_tx_ring_buf));
/* Enable the USART1 interrupt. */
nvic_enable_irq (NVIC_USART1_IRQ);
/* Map pins */
gpio_set_mode (GPIOA, GPIO_MODE_OUTPUT_50_MHZ,
GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART1_TX);
gpio_set_mode (GPIOA, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT,
GPIO_USART1_RX);
/* Setup UART1 parameters. */
usart_set_baudrate (USART1, 115200);
usart_set_databits (USART1, 8);
usart_set_stopbits (USART1, USART_STOPBITS_1);
usart_set_parity (USART1, USART_PARITY_NONE);
usart_set_flow_control (USART1, USART_FLOWCONTROL_NONE);
usart_set_mode (USART1, USART_MODE_TX_RX);
/* Enable USART1 Receive interrupt. */
USART_CR1 (USART1) |= USART_CR1_RXNEIE;
/* Finally enable USART1. */
usart_enable (USART1);
}
|
