I have also found this code from the examples on the website I bought it from using serial:
/****************************************************************
* Arduino MD25 example code *
* MD25 running in serial mode *
* *
* by James Henderson 2012 *
*****************************************************************/
#include <SoftwareSerial.h>
// Values of 0 being sent using serial.write() have to be cast as a byte to stop them being misinterpereted as NULL
// This is a bug with arduino 1
#define CMD (byte)0x00 // MD25 command byte of 0
#define WRITESP1 0x31 // Byte writes speed to motor 1
#define WRITEACCEL 0x33 // Byte writes a value of acceleration
#define RESETREG 0x35 // Byte resets encoders
#define SETMODE 0x34 // Byte sets mode
#define READIVS 0x2C // Byte reads motor currents and battery voltage
#define READENCS 0x25 // Byte reads both encoders
#define GET_VER 0x29
#define LCD_RX 0x02 // RX and TX pins used for LCD0303 serial port
#define LCD_TX 0x03
#define LCD03_HIDE_CUR 0x04
#define LCD03_CLEAR 0x0C
#define LCD03_SET_CUR 0x02
SoftwareSerial lcd03 = SoftwareSerial(LCD_RX, LCD_TX); // Define the serial port for the LCD03
long encValue = 0;
byte softwareRev = 0;
void setup(){
Serial.begin(38400);
lcd03.begin(9600);
Serial.write(CMD); // Set MD25 accelleration value
Serial.write(WRITEACCEL);
Serial.write(10);
delayMicroseconds(10); // Wait for this to be processed
Serial.write(CMD); // Reset the encoder registers to 0
Serial.write(RESETREG);
Serial.write(CMD); // Set mode to 2, Both motors controlled by writing to speed 1
Serial.write(SETMODE);
Serial.write(2);
Serial.write(CMD); // Get software version of MD25
Serial.write(GET_VER);
while(Serial.available() < 1){} // Wait for byte to become available
softwareRev = Serial.read();
lcd03.write(LCD03_CLEAR); // Clear the LCD03 screen
lcd03.write(LCD03_HIDE_CUR); // Hide the LCD03 cursor
}
void loop(){
while(encValue < 3000){ // While encoder 1 value less than 3000 move forward
Serial.write(CMD); // Set motors to drive forward at full speed
Serial.write(WRITESP1);
Serial.write(150);
encValue = readEncoder();
readVolts();
}
delay(100);
while(encValue > 100){
Serial.write(CMD); // Drive motors reverse at full speed
Serial.write(WRITESP1);
Serial.write(100);
encValue = readEncoder();
readVolts();
}
delay(100);
}
long readEncoder(){ // Function to read and display the value of both encoders, returns value of first encoder
long result1 = 0;
long result2 = 0;
Serial.write(CMD);
Serial.write(READENCS);
while(Serial.available() < 8){} // Wait for 8 bytes, first 4 encoder 1 values second 4 encoder 2 values
result1 = Serial.read(); // First byte for encoder 1, HH.
result1 <<= 8;
result1 += Serial.read(); // Second byte for encoder 1, HL
result1 <<= 8;
result1 += Serial.read(); // Third byte for encoder 1, LH
result1 <<= 8;
result1 += Serial.read(); // Fourth byte for encoder 1, LL
result2 = Serial.read();
result2 <<= 8;
result2 += Serial.read();
result2 <<= 8;
result2 += Serial.read();
result2 <<= 8;
result2 += Serial.read();
lcd03.write(LCD03_SET_CUR); // Set the LCD03 cursor position
lcd03.write(21);
lcd03.print("Encoder 1:"); // Displays data to the LCD03 screen
lcd03.print(result1,DEC);
lcd03.print(" "); // Print a blank space to clear any unwanted characters that are leftover on the LCD03 display
delay(5); // Delay for LCD03 to process data
lcd03.write(LCD03_SET_CUR);
lcd03.write(41);
lcd03.print("Encoder 2:");
lcd03.print(result2,DEC);
lcd03.print(" ");
return result1;
}
void readVolts(){ // Function reads current for both motors and battery voltage
byte batteryVolts, mot1_current, mot2_current = 0;
Serial.write(CMD);
Serial.write(READIVS); // Send byte to readbattery voltage and motor currents
while(Serial.available() < 3){} // Wait for the 3 bytes to become available then get them
batteryVolts = Serial.read();
mot1_current = Serial.read();
mot2_current = Serial.read();
lcd03.write(LCD03_SET_CUR);
lcd03.write(61);
lcd03.print("Mot1 I:");
lcd03.print(mot1_current,DEC);
lcd03.print(" Mot2 I:");
lcd03.print(mot2_current,DEC);
lcd03.print(" ");
delay(5);
lcd03.write(LCD03_SET_CUR);
lcd03.write(1);
lcd03.print("Rev:");
lcd03.print(softwareRev, DEC);
lcd03.print(" ");
lcd03.print("Volts:");
lcd03.print(batteryVolts/10,DEC); // Seperate whole number and descimal place of battery voltage and display
lcd03.print(".");
lcd03.print(batteryVolts%10,DEC);
lcd03.print(" ");
}