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
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
|
/******************************************************************************
* The MIT License
*
* Copyright (c) 2010 Perry Hung.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy,
* modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*****************************************************************************/
/**
* @file libmaple/usart.c
* @author Marti Bolivar <mbolivar@leaflabs.com>,
* Perry Hung <perry@leaflabs.com>
* @brief Portable USART routines
*/
#include <libmaple/usart.h>
/**
* @brief Initialize a serial port.
* @param dev Serial port to be initialized
*/
void usart_init(usart_dev *dev) {
rb_init(dev->rb, USART_RX_BUF_SIZE, dev->rx_buf);
rcc_clk_enable(dev->clk_id);
nvic_irq_enable(dev->irq_num);
}
/**
* @brief Enable a serial port.
*
* USART is enabled in single buffer transmission mode, multibuffer
* receiver mode, 8n1.
*
* Serial port must have a baud rate configured to work properly.
*
* @param dev Serial port to enable.
* @see usart_set_baud_rate()
*/
void usart_enable(usart_dev *dev) {
usart_reg_map *regs = dev->regs;
regs->CR1 = (USART_CR1_TE | USART_CR1_RE | USART_CR1_RXNEIE |
USART_CR1_M_8N1);
regs->CR1 |= USART_CR1_UE;
}
/**
* @brief Turn off a serial port.
* @param dev Serial port to be disabled
*/
void usart_disable(usart_dev *dev) {
/* FIXME this misbehaves (on F1) if you try to use PWM on TX afterwards */
usart_reg_map *regs = dev->regs;
/* TC bit must be high before disabling the USART */
while((regs->CR1 & USART_CR1_UE) && !(regs->SR & USART_SR_TC))
;
/* Disable UE */
regs->CR1 &= ~USART_CR1_UE;
/* Clean up buffer */
usart_reset_rx(dev);
}
/**
* @brief Nonblocking USART transmit
* @param dev Serial port to transmit over
* @param buf Buffer to transmit
* @param len Maximum number of bytes to transmit
* @return Number of bytes transmitted
*/
uint32 usart_tx(usart_dev *dev, const uint8 *buf, uint32 len) {
usart_reg_map *regs = dev->regs;
uint32 txed = 0;
while ((regs->SR & USART_SR_TXE) && (txed < len)) {
regs->DR = buf[txed++];
}
return txed;
}
/**
* @brief Nonblocking USART receive.
* @param dev Serial port to receive bytes from
* @param buf Buffer to store received bytes into
* @param len Maximum number of bytes to store
* @return Number of bytes received
*/
uint32 usart_rx(usart_dev *dev, uint8 *buf, uint32 len) {
uint32 rxed = 0;
while (usart_data_available(dev) && rxed < len) {
*buf++ = usart_getc(dev);
rxed++;
}
return rxed;
}
/**
* @brief Transmit an unsigned integer to the specified serial port in
* decimal format.
*
* This function blocks until the integer's digits have been
* completely transmitted.
*
* @param dev Serial port to send on
* @param val Number to print
*/
void usart_putudec(usart_dev *dev, uint32 val) {
char digits[12];
int i = 0;
do {
digits[i++] = val % 10 + '0';
val /= 10;
} while (val > 0);
while (--i >= 0) {
usart_putc(dev, digits[i]);
}
}
|
