Micro-controller : SainSmart Mega 2560
Motor Shield: Osepp Motor Shield V1.0
I am trying to implement Radio Frequency communication on my wheeled robot however when the motors are running the radio frequency code will not receive messages.
The motor shield uses pins 4,7,8,12
I have setup the radio frequency to occur on pins 22,23 ,5
I see this reference to Why does VirtualWire conflicts with PWM signal in Arduino/ATmega328 pin D10? but am not sure if this applies to my situation.
How do I get Radio Frequency receiver/transmitter to work while motor shield in use?
code demonstrating the situation:
#include <RH_ASK.h>
#include <SPI.h> // Not actually used but needed to compile
RH_ASK driver(2000, 22, 23, 5,true); // ESP8266: do not use pin 11
/// *************************
// MOTOR SETUP
/// *************************
// Arduino pins for the shift register
#define MOTORLATCH 12
#define MOTORCLK 4
#define MOTORENABLE 7
#define MOTORDATA 8
// 8-bit bus after the 74HC595 shift register
// (not Arduino pins)
// These are used to set the direction of the bridge driver.
#define MOTOR1_A 2
#define MOTOR1_B 3
#define MOTOR2_A 1
#define MOTOR2_B 4
#define MOTOR3_A 5
#define MOTOR3_B 7
#define MOTOR4_A 0
#define MOTOR4_B 6
// Arduino pins for the PWM signals.
#define MOTOR1_PWM 11
#define MOTOR2_PWM 3
#define MOTOR3_PWM 6
#define MOTOR4_PWM 5
#define SERVO1_PWM 10
#define SERVO2_PWM 9
// Codes for the motor function.
#define FORWARD 1
#define BACKWARD 2
#define BRAKE 3
#define RELEASE 4
void setup()
{
Serial.begin(9600); // Debugging only
if (!driver.init())
Serial.println("init failed");
//comment out code below to allow receiver to read radio frequency communication
//BEGIN
motor(1, FORWARD, 255);
motor(2, FORWARD, 255);
motor(4, FORWARD, 255);
motor(3, FORWARD, 255);
//END
}
void loop()
{
uint8_t buf[RH_ASK_MAX_MESSAGE_LEN];
uint8_t buflen = sizeof(buf);
if (driver.recv(buf, &buflen)) // Non-blocking
{
int i=0;
// Message with a good checksum received, dump it.
driver.printBuffer("Got:", buf, buflen);
buf[5]= '\0';
Serial.println((char*)buf);
}
}
void motor(int nMotor, int command, int speed)
{
int motorA, motorB;
if (nMotor >= 1 && nMotor <= 4)
{
switch (nMotor)
{
case 1:
motorA = MOTOR1_A;
motorB = MOTOR1_B;
break;
case 2:
motorA = MOTOR2_A;
motorB = MOTOR2_B;
break;
case 3:
motorA = MOTOR3_A;
motorB = MOTOR3_B;
break;
case 4:
motorA = MOTOR4_A;
motorB = MOTOR4_B;
break;
default:
break;
}
switch (command)
{
case FORWARD:
motor_output (motorA, HIGH, speed);
motor_output (motorB, LOW, -1); // -1: no PWM set
break;
case BACKWARD:
motor_output (motorA, LOW, speed);
motor_output (motorB, HIGH, -1); // -1: no PWM set
break;;
case RELEASE:
motor_output (motorA, LOW, 0); // 0: output floating.
motor_output (motorB, LOW, -1); // -1: no PWM set
break;
default:
break;
}
}
}
void motor_output (int output, int high_low, int speed)
{
int motorPWM;
switch (output)
{
case MOTOR1_A:
case MOTOR1_B:
motorPWM = MOTOR1_PWM;
break;
case MOTOR2_A:
case MOTOR2_B:
motorPWM = MOTOR2_PWM;
break;
case MOTOR3_A:
case MOTOR3_B:
motorPWM = MOTOR3_PWM;
break;
case MOTOR4_A:
case MOTOR4_B:
motorPWM = MOTOR4_PWM;
break;
default:
speed = -3333;
break;
}
if (speed != -3333)
{
shiftWrite(output, high_low);
if (speed >= 0 && speed <= 255)
{
analogWrite(motorPWM, speed);
}
}
}
void shiftWrite(int output, int high_low)
{
static int latch_copy;
static int shift_register_initialized = false;
if (!shift_register_initialized)
{
// Set pins for shift register to output
pinMode(MOTORLATCH, OUTPUT);
pinMode(MOTORENABLE, OUTPUT);
pinMode(MOTORDATA, OUTPUT);
pinMode(MOTORCLK, OUTPUT);
// Set pins for shift register to default value (low);
digitalWrite(MOTORDATA, LOW);
digitalWrite(MOTORLATCH, LOW);
digitalWrite(MOTORCLK, LOW);
// Enable the shift register, set Enable pin Low.
digitalWrite(MOTORENABLE, LOW);
// start with all outputs (of the shift register) low
latch_copy = 0;
shift_register_initialized = true;
}
bitWrite(latch_copy, output, high_low);
shiftOut(MOTORDATA, MOTORCLK, MSBFIRST, latch_copy);
delayMicroseconds(5); // For safety, not really needed.
digitalWrite(MOTORLATCH, HIGH);
delayMicroseconds(5); // For safety, not really needed.
digitalWrite(MOTORLATCH, LOW);
}
