Here is a picture of the prototype with a MSP430F5529 on top running things:
Here is the test code and a description of the circuit for those that are interested:
/*
This is a motor control circuit using a TI L293DNE motor
controller used with a MSP432-F5529LP to drive
a toy Tamiya tank with two motors.
Note that the Tamiya motors operate at 3V and the feed is
routed through LD1117AV33's to get the voltage down.
Note: Do not use PWM below about 50% or motors can stall -
suggest using PWM to balance motor speed only.
L293DNE
-------
1 MCU 39 (P2.4) - Enable pin
2 MCU 2 (P6.5) - Left Motor Logic pin 1
3 Left Motor Terminal 1
4 Heat sink / ground
5 Heat sink / ground
6 Left Motor Terminal 2
7 MCU 3 (P3.4) - Left Motor Logic pin 2
8 Motor Power Supply - 5.0V reduced to 3.3V for Tamiya
9 MCU 40 (P2.5) - Enable pin
10 MCU 4 (P3.3) - Right Motor Logic pin 1
11 Right Motor Terminal 1
12 Heat sink / ground
13 Heat sink / ground
14 Right Motor Terminal 2
15 MCU 5 (P1.6) - Right Motor Logic pin 2
16 IC Power Supply - 5.0V (used separate supply than LP)
LD1117AV33 - connect all motor terminal through these (4)
----------
1 5.0 V
2 GND
3 3.3 V
Tamiya Motors
-------------
Connect terminals to 3.3 V output from LD1117AV33 above
Capacitors
----------
See LD1117AV33 datasheet
suggests 10uF on output and 100nF on input
Frank Milburn 22 Feb 2015
*/
const int leftMotor1Pin = 2;
const int leftMotor2Pin = 3;
const int leftEnablePin = 39;
const int rightMotor1Pin = 4;
const int rightMotor2Pin = 5;
const int rightEnablePin = 40;
void setup()
{
pinMode(leftMotor1Pin, OUTPUT);
pinMode(leftMotor2Pin, OUTPUT);
pinMode(leftEnablePin, OUTPUT);
pinMode(rightMotor1Pin, OUTPUT);
pinMode(rightMotor2Pin, OUTPUT);
pinMode(rightEnablePin, OUTPUT);
Serial.begin(9600);
Serial.println("Starting motor test");
}
void loop()
{
Serial.println("Forward"); // start with left side
digitalWrite(leftMotor1Pin, LOW); // set leg 1 of H-bridge low
digitalWrite(leftMotor2Pin, HIGH); // set leg 2 of the H-bridge high
digitalWrite(rightMotor1Pin, LOW); // now right side
digitalWrite(rightMotor2Pin, HIGH);
digitalWrite(leftEnablePin, HIGH); // enable motors on
digitalWrite(rightEnablePin, HIGH);
delay(2000);
Serial.println("Stop");
digitalWrite(leftEnablePin, LOW); // disable the motors
digitalWrite(rightEnablePin, LOW);
delay(1000);
Serial.println("Backwards");
digitalWrite(leftMotor1Pin, HIGH); // Reverse the motors
digitalWrite(leftMotor2Pin, LOW);
digitalWrite(rightMotor1Pin, HIGH);
digitalWrite(rightMotor2Pin, LOW);
digitalWrite(leftEnablePin, HIGH); // enable motors on
digitalWrite(rightEnablePin, HIGH);
delay(2000);
Serial.println("Stop");
digitalWrite(leftEnablePin, LOW); // disable the motors
digitalWrite(rightEnablePin, LOW);
delay(1000);
Serial.println("Forward 3/4 speed");
digitalWrite(leftMotor1Pin, LOW); // Set both sides forward
digitalWrite(leftMotor2Pin, HIGH);
digitalWrite(rightMotor1Pin, LOW);
digitalWrite(rightMotor2Pin, HIGH);
analogWrite(leftEnablePin, 192); // enable motors on at reduced speed with PWM
analogWrite(rightEnablePin, 192);
delay(2000);
Serial.println("Stop");
digitalWrite(leftEnablePin, LOW); // disable the motors
digitalWrite(rightEnablePin, LOW);
delay(1000);
}
