blob: 4e8fd3bcdfb152fab3a2f02ca649dd544999f49a (
plain)
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
|
/* Copyright 2020
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include "spi_master.h"
#include "timer.h"
#if defined(__AVR_AT90USB162__) || defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__) || defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__) || defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__)
# define SPI_SCK_PIN B1
# define SPI_MOSI_PIN B2
# define SPI_MISO_PIN B3
#elif defined(__AVR_ATmega32A__)
# define SPI_SCK_PIN B7
# define SPI_MOSI_PIN B5
# define SPI_MISO_PIN B6
#elif defined(__AVR_ATmega328P__) || defined(__AVR_ATmega328__)
# define SPI_SCK_PIN B5
# define SPI_MOSI_PIN B3
# define SPI_MISO_PIN B4
#endif
#ifndef SPI_TIMEOUT
# define SPI_TIMEOUT 100
#endif
static pin_t currentSlavePin = NO_PIN;
static uint8_t currentSlaveConfig = 0;
static bool currentSlave2X = false;
void spi_init(void) {
writePinHigh(SPI_SS_PIN);
setPinOutput(SPI_SCK_PIN);
setPinOutput(SPI_MOSI_PIN);
setPinInput(SPI_MISO_PIN);
SPCR = (_BV(SPE) | _BV(MSTR));
}
bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor) {
if (currentSlavePin != NO_PIN || slavePin == NO_PIN) {
return false;
}
currentSlaveConfig = 0;
if (lsbFirst) {
currentSlaveConfig |= _BV(DORD);
}
switch (mode) {
case 1:
currentSlaveConfig |= _BV(CPHA);
break;
case 2:
currentSlaveConfig |= _BV(CPOL);
break;
case 3:
currentSlaveConfig |= (_BV(CPOL) | _BV(CPHA));
break;
}
uint16_t roundedDivisor = 1;
while (roundedDivisor < divisor) {
roundedDivisor <<= 1;
}
switch (roundedDivisor) {
case 16:
currentSlaveConfig |= _BV(SPR0);
break;
case 64:
currentSlaveConfig |= _BV(SPR1);
break;
case 128:
currentSlaveConfig |= (_BV(SPR1) | _BV(SPR0));
break;
case 2:
currentSlave2X = true;
break;
case 8:
currentSlave2X = true;
currentSlaveConfig |= _BV(SPR0);
break;
case 32:
currentSlave2X = true;
currentSlaveConfig |= _BV(SPR1);
break;
}
SPCR |= currentSlaveConfig;
if (currentSlave2X) {
SPSR |= _BV(SPI2X);
}
currentSlavePin = slavePin;
setPinOutput(currentSlavePin);
writePinLow(currentSlavePin);
return true;
}
spi_status_t spi_write(uint8_t data) {
SPDR = data;
uint16_t timeout_timer = timer_read();
while (!(SPSR & _BV(SPIF))) {
if ((timer_read() - timeout_timer) >= SPI_TIMEOUT) {
return SPI_STATUS_TIMEOUT;
}
}
return SPDR;
}
spi_status_t spi_read() {
SPDR = 0x00; // Dummy
uint16_t timeout_timer = timer_read();
while (!(SPSR & _BV(SPIF))) {
if ((timer_read() - timeout_timer) >= SPI_TIMEOUT) {
return SPI_STATUS_TIMEOUT;
}
}
return SPDR;
}
spi_status_t spi_transmit(const uint8_t *data, uint16_t length) {
spi_status_t status;
for (uint16_t i = 0; i < length; i++) {
status = spi_write(data[i]);
if (status < 0) {
return status;
}
}
return SPI_STATUS_SUCCESS;
}
spi_status_t spi_receive(uint8_t *data, uint16_t length) {
spi_status_t status;
for (uint16_t i = 0; i < length; i++) {
status = spi_read();
if (status >= 0) {
data[i] = status;
} else {
return status;
}
}
return SPI_STATUS_SUCCESS;
}
void spi_stop(void) {
if (currentSlavePin != NO_PIN) {
setPinOutput(currentSlavePin);
writePinHigh(currentSlavePin);
currentSlavePin = NO_PIN;
SPSR &= ~(_BV(SPI2X));
SPCR &= ~(currentSlaveConfig);
currentSlaveConfig = 0;
currentSlave2X = false;
}
}
|
