We are working on rapid response vent project and are coming across an issue with the I2C on the Due. The Adafruit Motor Shield V2 uses SCL1 and SDA1, which do not have pull up resistors. Therefore we cut those pins and rewired to use SCL and SDA (Pins 21 and 20).
After reviewing the Adafruit_MotorShield.cpp file (link below) we noticed that you could pass argument wire or wire1 into the below function to define which I2C bus to use. However, trying both arguments it is still using the SCL1 and SDA1 bus.
Below is the function from Adafruit_MotorShield.cpp
/**************************************************************************/
/*!
@brief Initialize the I2C hardware and PWM driver, then turn off all pins.
@param freq
The PWM frequency for the driver, used for speed control and microstepping.
By default we use 1600 Hz which is a little audible but efficient.
@param theWire
A pointer to an optional I2C interface. If not provided, we use Wire or
Wire1 (on Due)
*/
/**************************************************************************/
void Adafruit_MotorShield::begin(uint16_t freq, TwoWire *theWire) {
if (!theWire) {
#if defined(ARDUINO_SAM_DUE)
_i2c = &Wire1;
#else
_i2c = &Wire;
#endif
} else {
_i2c = theWire;
}
// init PWM w/_freq
_i2c->begin();
_pwm.begin();
_freq = freq;
_pwm.setPWMFreq(_freq); // This is the maximum PWM frequency
for (uint8_t i = 0; i < 16; i++)
_pwm.setPWM(i, 0, 0);
}
Our code for testing bus is:
/*
This is a test sketch for the Adafruit assembled Motor Shield for Arduino v2
It won't work with v1.x motor shields! Only for the v2's with built in PWM
control
For use with the Adafruit Motor Shield v2
----> http://www.adafruit.com/products/1438
*/
#include <Wire.h>
#include <Adafruit_MotorShield.h>
// Create the motor shield object with the default I2C address
Adafruit_MotorShield AFMS = Adafruit_MotorShield();
// Or, create it with a different I2C address (say for stacking)
// Adafruit_MotorShield AFMS = Adafruit_MotorShield(0x61);
// Select which 'port' M1, M2, M3 or M4. In this case, M1
Adafruit_DCMotor *myMotor = AFMS.getMotor(1);
// You can also make another motor on port M2
//Adafruit_DCMotor *myOtherMotor = AFMS.getMotor(2);
void setup() {
Serial.begin(9600); // set up Serial library at 9600 bps
Serial.println("Adafruit Motorshield v2 - DC Motor test!");
AFMS.begin(1600, &Wire); // create with the default frequency 1.6KHz
//AFMS.begin(1000); // OR with a different frequency, say 1KHz
// Set the speed to start, from 0 (off) to 255 (max speed)
myMotor->setSpeed(150);
myMotor->run(FORWARD);
// turn on motor
myMotor->run(RELEASE);
}
void loop() {
uint8_t i;
Serial.print("tick");
myMotor->run(FORWARD);
for (i=0; i<255; i++) {
myMotor->setSpeed(i);
delay(10);
}
for (i=255; i!=0; i--) {
myMotor->setSpeed(i);
delay(10);
}
Serial.print("tock");
myMotor->run(BACKWARD);
for (i=0; i<255; i++) {
myMotor->setSpeed(i);
delay(10);
}
for (i=255; i!=0; i--) {
myMotor->setSpeed(i);
delay(10);
}
Serial.print("tech");
myMotor->run(RELEASE);
delay(1000);
}