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
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
|
/******************************************************************************
* 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 usart.c
* @brief USART control routines
*/
#include "usart.h"
/*
* Devices
*/
static ring_buffer usart1_rb;
static usart_dev usart1 = {
.regs = USART1_BASE,
.rb = &usart1_rb,
.max_baud = 4500000UL,
.clk_id = RCC_USART1,
.irq_num = NVIC_USART1
};
usart_dev *USART1 = &usart1;
static ring_buffer usart2_rb;
static usart_dev usart2 = {
.regs = USART2_BASE,
.rb = &usart2_rb,
.max_baud = 2250000UL,
.clk_id = RCC_USART2,
.irq_num = NVIC_USART2
};
usart_dev *USART2 = &usart2;
static ring_buffer usart3_rb;
static usart_dev usart3 = {
.regs = USART3_BASE,
.rb = &usart3_rb,
.max_baud = 2250000UL,
.clk_id = RCC_USART3,
.irq_num = NVIC_USART3
};
usart_dev *USART3 = &usart3;
#ifdef STM32_HIGH_DENSITY
static ring_buffer uart4_rb;
static usart_dev uart4 = {
.regs = UART4_BASE,
.rb = &uart4_rb,
.max_baud = 2250000UL,
.clk_id = RCC_UART4,
.irq_num = NVIC_UART4
};
usart_dev *UART4 = &uart4;
static ring_buffer uart5_rb;
static usart_dev uart5 = {
.regs = UART5_BASE,
.rb = &uart5_rb,
.max_baud = 2250000UL,
.clk_id = RCC_UART5,
.irq_num = NVIC_UART5
};
usart_dev *UART5 = &uart5;
#endif
/**
* @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 Configure a serial port's baud rate.
*
* @param dev Serial port to be configured
* @param clock_speed Clock speed, in megahertz.
* @param baud Baud rate for transmit/receive.
*/
void usart_set_baud_rate(usart_dev *dev, uint32 clock_speed, uint32 baud) {
uint32 integer_part;
uint32 fractional_part;
uint32 tmp;
/* See ST RM0008 for the details on configuring the baud rate register */
integer_part = (25 * clock_speed) / (4 * baud);
tmp = (integer_part / 100) << 4;
fractional_part = integer_part - (100 * (tmp >> 4));
tmp |= (((fractional_part * 16) + 50) / 100) & ((uint8)0x0F);
dev->regs->BRR = (uint16)tmp;
}
/**
* @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;
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 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 Call a function on each USART.
* @param fn Function to call.
*/
void usart_foreach(void (*fn)(usart_dev *dev)) {
fn(USART1);
fn(USART2);
fn(USART3);
#ifdef STM32_HIGH_DENSITY
fn(UART4);
fn(UART5);
#endif
}
/**
* @brief Print a null-terminated string to the specified serial port.
* @param dev Serial port to send the string on
* @param str String to send
*/
void usart_putstr(usart_dev *dev, const char* str) {
char ch;
while ((ch = *(str++)) != '\0') {
usart_putc(dev, ch);
}
}
/**
* @brief Print an unsigned integer to the specified serial port.
*
* @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]);
}
}
/*
* Interrupt handlers.
*/
static inline void usart_irq(usart_dev *dev) {
#ifdef USART_SAFE_INSERT
/* If the buffer is full and the user defines USART_SAFE_INSERT,
* ignore new bytes. */
rb_safe_insert(dev->rb, (uint8)dev->regs->DR);
#else
/* By default, push bytes around in the ring buffer. */
rb_push_insert(dev->rb, (uint8)dev->regs->DR);
#endif
}
void __irq_usart1(void) {
usart_irq(USART1);
}
void __irq_usart2(void) {
usart_irq(USART2);
}
void __irq_usart3(void) {
usart_irq(USART3);
}
#ifdef STM32_HIGH_DENSITY
void __irq_uart4(void) {
usart_irq(UART4);
}
void __irq_uart5(void) {
usart_irq(UART5);
}
#endif
|
