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/*
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(PC3, PC2);
}
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);
}
}
}
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