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
|
/*
Copyright (C) 2009 Jeff Hoefs. All rights reserved.
Copyright (C) 2009 Shigeru Kobayashi. All rights reserved.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
See file LICENSE.txt for further informations on licensing terms.
*/
#include <Wire.h>
#include <Firmata.h>
#define I2C_WRITE B00000000
#define I2C_READ B00001000
#define I2C_READ_CONTINUOUSLY B00010000
#define I2C_STOP_READING B00011000
#define I2C_READ_WRITE_MODE_MASK B00011000
#define MAX_QUERIES 8
unsigned long currentMillis; // store the current value from millis()
unsigned long nextExecuteMillis; // for comparison with currentMillis
unsigned int samplingInterval = 32; // default sampling interval is 33ms
unsigned int i2cReadDelayTime = 0; // default delay time between i2c read request and Wire.requestFrom()
unsigned int powerPinsEnabled = 0; // use as boolean to prevent enablePowerPins from being called more than once
#define MINIMUM_SAMPLING_INTERVAL 10
#define REGISTER_NOT_SPECIFIED -1
struct i2c_device_info {
byte addr;
byte reg;
byte bytes;
};
i2c_device_info query[MAX_QUERIES];
byte i2cRxData[32];
boolean readingContinuously = false;
byte queryIndex = 0;
void readAndReportData(byte address, int theRegister, byte numBytes)
{
if (theRegister != REGISTER_NOT_SPECIFIED) {
Wire.beginTransmission(address);
Wire.send((byte)theRegister);
Wire.endTransmission();
delayMicroseconds(i2cReadDelayTime); // delay is necessary for some devices such as WiiNunchuck
}
else {
theRegister = 0; // fill the register with a dummy value
}
Wire.requestFrom(address, numBytes);
// check to be sure correct number of bytes were returned by slave
if(numBytes == Wire.available()) {
i2cRxData[0] = address;
i2cRxData[1] = theRegister;
for (int i = 0; i < numBytes; i++) {
i2cRxData[2 + i] = Wire.receive();
}
// send slave address, register and received bytes
Firmata.sendSysex(I2C_REPLY, numBytes + 2, i2cRxData);
}
else {
if(numBytes > Wire.available()) {
Firmata.sendString("I2C Read Error: Too many bytes received");
} else {
Firmata.sendString("I2C Read Error: Too few bytes received");
}
}
}
void sysexCallback(byte command, byte argc, byte *argv)
{
byte mode;
byte slaveAddress;
byte slaveRegister;
byte data;
int delayTime;
if (command == I2C_REQUEST) {
mode = argv[1] & I2C_READ_WRITE_MODE_MASK;
slaveAddress = argv[0];
switch(mode) {
case I2C_WRITE:
Wire.beginTransmission(slaveAddress);
for (byte i = 2; i < argc; i += 2) {
data = argv[i] + (argv[i + 1] << 7);
Wire.send(data);
}
Wire.endTransmission();
delayMicroseconds(70); // TODO is this needed?
break;
case I2C_READ:
if (argc == 6) {
// a slave register is specified
slaveRegister = argv[2] + (argv[3] << 7);
data = argv[4] + (argv[5] << 7); // bytes to read
readAndReportData(slaveAddress, (int)slaveRegister, data);
}
else {
// a slave register is NOT specified
data = argv[2] + (argv[3] << 7); // bytes to read
readAndReportData(slaveAddress, (int)REGISTER_NOT_SPECIFIED, data);
}
break;
case I2C_READ_CONTINUOUSLY:
if ((queryIndex + 1) >= MAX_QUERIES) {
// too many queries, just ignore
Firmata.sendString("too many queries");
break;
}
query[queryIndex].addr = slaveAddress;
query[queryIndex].reg = argv[2] + (argv[3] << 7);
query[queryIndex].bytes = argv[4] + (argv[5] << 7);
readingContinuously = true;
queryIndex++;
break;
case I2C_STOP_READING:
readingContinuously = false;
queryIndex = 0;
break;
default:
break;
}
}
else if (command == SAMPLING_INTERVAL) {
samplingInterval = argv[0] + (argv[1] << 7);
if (samplingInterval < MINIMUM_SAMPLING_INTERVAL) {
samplingInterval = MINIMUM_SAMPLING_INTERVAL;
}
samplingInterval -= 1;
Firmata.sendString("sampling interval");
}
else if (command == I2C_CONFIG) {
delayTime = (argv[4] + (argv[5] << 7)); // MSB
delayTime = (delayTime << 8) + (argv[2] + (argv[3] << 7)); // add LSB
if((argv[0] + (argv[1] << 7)) > 0) {
enablePowerPins(PORTC3, PORTC2);
}
if(delayTime > 0) {
i2cReadDelayTime = delayTime;
}
if(argc > 6) {
// If you extend I2C_Config, handle your data here
}
}
}
void systemResetCallback()
{
readingContinuously = false;
queryIndex = 0;
}
/* reference: BlinkM_funcs.h by Tod E. Kurt, ThingM, http://thingm.com/ */
// Enables Pins A2 and A3 to be used as GND and Power
// so that I2C devices can be plugged directly
// into Arduino header (pins A2 - A5)
static void enablePowerPins(byte pwrpin, byte gndpin)
{
if(powerPinsEnabled == 0) {
DDRC |= _BV(pwrpin) | _BV(gndpin);
PORTC &=~ _BV(gndpin);
PORTC |= _BV(pwrpin);
powerPinsEnabled = 1;
Firmata.sendString("Power pins enabled");
delay(100);
}
}
void setup()
{
Firmata.setFirmwareVersion(2, 0);
Firmata.attach(START_SYSEX, sysexCallback);
Firmata.attach(SYSTEM_RESET, systemResetCallback);
for (int i = 0; i < TOTAL_DIGITAL_PINS; ++i) {
pinMode(i, OUTPUT);
}
/* I2C data is not reliable at higher baud rates, you'll need to change the
baud rate on the host computer as well. To get a firmware running with
minimal effort, you can try using the default baud rate (115200) */
Firmata.begin(38400);
Wire.begin();
}
void loop()
{
while (Firmata.available()) {
Firmata.processInput();
}
currentMillis = millis();
if (currentMillis > nextExecuteMillis) {
nextExecuteMillis = currentMillis + samplingInterval;
for (byte i = 0; i < queryIndex; i++) {
readAndReportData(query[i].addr, query[i].reg, query[i].bytes);
}
}
}
|
