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
|
#include "driver/soft_i2c.h"
#include "driver/gpio.h"
#include "arch.h"
#ifndef F_I2C
#define F_I2C 100000
#endif
#ifdef SOFTI2C_TIMER
#ifdef TIMER_CYCLES
#error "SOFTI2C_TIMER and TIMER_CYCLES are mutually exclusive"
#endif
#include "driver/timer.h"
volatile unsigned char timer_done = 0;
#endif
#ifdef SOFTI2C_PULLUP_INTERNAL
#define SDA_HIGH gpio.input(sda, 1)
#define SDA_LOW gpio.output(sda, 0)
#define SCL_HIGH gpio.input(scl, 1)
#define SCL_LOW gpio.output(scl, 0)
#elif SOFTI2C_PULLUP_EXTERNAL
#define SDA_HIGH { gpio.input(sda); gpio.write(sda_pull, 1); }
#define SDA_LOW { gpio.write(sda_pull, 0); gpio.output(sda); }
#define SCL_HIGH { gpio.input(scl); gpio.write(scl_pull, 1); }
#define SCL_LOW { gpio.write(scl_pull, 0); gpio.output(scl); }
#else /* !SOFTI2C_PULLUP_{INTERNAL,EXTERNAL} */
#define SDA_HIGH gpio.input(sda)
#define SDA_LOW gpio.output(sda)
#define SCL_HIGH gpio.input(scl)
#define SCL_LOW gpio.output(scl)
#endif /* SOFTI2C_PULLUP */
inline void i2c_wait()
{
#ifdef SOFTI2C_TIMER
/*
* Note: On MSP430, if F_CPU / F_I2C < 60 (approx.), i2c_wait() does not
* work. Probably related to missed interrupts / not enough cycles between
* start and idle? We work around this for now by simulating an immediate
* return in these cases.
*/
#if MULTIPASS_ARCH_msp430fr5969lp && ((F_CPU / F_I2C) < 60)
#else
timer_done = 0;
timer.start(1);
while (!timer_done) {
arch.idle();
}
timer.stop();
#endif
#else /* !SOFTI2C_TIMER */
#if (500000UL / F_I2C) > 11
arch.delay_us((500000UL / F_I2C) - 10);
#else
arch.delay_us(500000UL / F_I2C);
#endif
#endif /* SOFTI2C_TIMER */
}
signed char SoftI2C::setup()
{
#ifdef SOFTI2C_PULLUP_EXTERNAL
gpio.output(sda_pull);
gpio.output(scl_pull);
#endif
#ifdef SOFTI2C_PULLUP_FIXED_GPIO
#if MULTIPASS_ARCH_msp430fr5969lp
gpio.output(GPIO::p1_4, 1);
gpio.output(GPIO::p1_5, 1);
#elif MULTIPASS_ARCH_msp430fr5994lp
gpio.output(GPIO::p8_2, 1);
gpio.output(GPIO::p8_3, 1);
#else
#error "softi2c_pullup=gpio not supported on this architecture"
#endif /* MULTIPASS_ARCH_* */
#endif /* SOFTI2C_PULLUP_FIXED_GPIO */
SDA_HIGH;
SCL_HIGH;
#ifdef SOFTI2C_TIMER
/*
* I2C frequency is the time between two SCL low->high transitions
* (or high->low, whatever you prefer). For the timer, we need to set the
* time between SCL low->high and the following high->low transition
* (and vice versa), which is twice the desired I2C frequency. Also,
* timer.setup wants kHz and not Hz, so we have
* Timer Freq [kHz] = I2C Freq [Hz] * 2 / 1000
*/
timer.setup_khz(F_I2C / 500);
#endif
return 0;
}
void SoftI2C::start()
{
SDA_HIGH;
SCL_HIGH;
i2c_wait(); // t_{SU,STA} >= 4.7 µs (für Sr)
SDA_LOW;
i2c_wait(); // t_{HD,STA} >= 4 µs
SCL_LOW;
i2c_wait();
}
void SoftI2C::stop()
{
SCL_LOW;
SDA_LOW;
i2c_wait();
SCL_HIGH;
i2c_wait(); // t_{SU,STO} >= 4 µs
SDA_HIGH;
i2c_wait(); // t_{BUF} >= 4.7 µs
}
bool SoftI2C::tx(unsigned char byte)
{
unsigned char got_ack = 0;
for (unsigned char i = 0; i <= 8; i++) {
if ((byte & 0x80) || (i == 8)) {
SDA_HIGH;
} else {
SDA_LOW;
}
byte <<= 1;
i2c_wait();
SCL_HIGH;
i2c_wait();
while (!gpio.read(scl)) ;
if (i == 8) {
if (!gpio.read(sda)) {
got_ack = 1;
}
}
SCL_LOW;
}
return got_ack;
}
unsigned char SoftI2C::rx(bool send_ack)
{
unsigned char byte = 0;
SDA_HIGH;
for (unsigned char i = 0; i <= 8; i++) {
i2c_wait();
SCL_HIGH;
i2c_wait();
while (!gpio.read(scl)) ;
if ((i < 8) && gpio.read(sda)) {
byte |= 1 << (7 - i);
}
SCL_LOW;
if ((i == 7) && send_ack) {
SDA_LOW;
} else if ((i == 8) && send_ack) {
SDA_HIGH;
}
}
return byte;
}
void SoftI2C::scan(unsigned int *results)
{
unsigned char i2caddr;
for (unsigned char address = 0; address < 128; address++) {
i2caddr = (address << 1) | 0;
start();
if (tx(i2caddr)) {
results[address / (8 * sizeof(unsigned int))] |= 1 << (address % (8 * sizeof(unsigned int)));
stop();
}
}
stop();
}
signed char SoftI2C::xmit(unsigned char address,
unsigned char tx_len, unsigned char *tx_buf,
unsigned char rx_len, unsigned char *rx_buf)
{
unsigned char i;
if (tx_len) {
start();
tx((address << 1) | 0);
for (i = 0; i < tx_len; i++) {
tx(tx_buf[i]);
}
}
if (rx_len) {
start();
tx((address << 1) | 1);
for (i = 1; i <= rx_len; i++) {
rx_buf[i-1] = rx((i < rx_len) * 1);
}
}
stop();
return 0;
}
#ifdef SOFTI2C_TIMER
ON_TIMER_INTERRUPT_head
timer_done = 1;
ON_TIMER_INTERRUPT_tail
#endif
#if SOFTI2C_PULLUP_EXTERNAL
#ifdef MULTIPASS_ARCH_msp430fr5969lp
SoftI2C i2c(GPIO::p1_6, GPIO::p1_7, GPIO::p1_4, GPIO::p1_5);
#elif MULTIPASS_ARCH_msp430fr5969lp
SoftI2C i2c(GPIO::p5_0, GPIO::p5_1, GPIO::p8_2, GPIO::p8_3);
#else
#error "softi2c_pullup = external not supported on this architecture"
#endif /* MULTIPASS_ARCH_* */
#else
#ifdef MULTIPASS_ARCH_esp8266
SoftI2C i2c(GPIO::d6, GPIO::d7);
#elif MULTIPASS_ARCH_arduino_nano
SoftI2C i2c(GPIO::pc4, GPIO::pc5);
#elif MULTIPASS_ARCH_blinkenrocket
SoftI2C i2c(GPIO::pc4, GPIO::pc5);
#elif MULTIPASS_ARCH_msp430fr5969lp
SoftI2C i2c(GPIO::p1_6, GPIO::p1_7);
#elif MULTIPASS_ARCH_msp430fr5994lp
SoftI2C i2c(GPIO::p5_0, GPIO::p5_1);
#elif MULTIPASS_ARCH_posix
SoftI2C i2c(GPIO::px00, GPIO::px01);
#endif /* MULTIPASS_ARCH_* */
#endif /* !SOFTI2C_PULLUP_EXTERNAL */
|
