Code:

# L298n H-Bridge Test Script
# Author: Rich Pyke
# Version: 1.3
# Last Updated: 2014-09-01

# Set Enable pins high
Set(D4, On)
Set(D5, On)

# Move Channel 1 Direction 1 for 5 seconds
Print("Channel 1 Forwards")
Set(D0, On)
Set(D1, Off)
Sleep(5000)

# Move Channel 1 Direction 2 for 5 seconds
Print("Channel 1 Reverse")
Set(D0, Off)
Set(D1, On)
Sleep(5000)

# Stop Channel 1
Print("Channel 1 Stopped")
Set(D0, Off)
Set(D1, Off)

# Move Channel 2 Direction 1 for 5 seconds
Print("Channel 2 Forwards")
Set(D2, On)
Set(D3, Off)
Sleep(5000)

# Move Channel 2 Direction 2 for 5 seconds
Print("Channel 2 Reverse")
Set(D2, Off)
Set(D3, On)
Sleep(5000)

# Stop Channel 2
Print("Channel 2 Stopped")
Set(D2, Off)
Set(D3, Off)

# PWM Ramping Test
# Kill both Enables
Set(D4, Off)
Set(D5, Off)

# Set H-Bridge Channels 1 and 2 for Direction 1
Set(D0, On)
Set(D1, Off)
Set(D2, On)
Set(D3, Off)

# Begin slow ramp up of PWM from 0 to 100
Print("Ramp Up Test")
$PWM_Speed = 0
RepeatWhile($PWM_Speed < 100)
$PWM_Speed++
PWM(D4, $PWM_Speed)
PWM(D5, $PWM_Speed)
Print("Speed: " + $PWM_Speed)
Sleep(50)
EndRepeatWhile

# Begin slow ramp down of PWM from 100 to 0
Print("Ramp Down Test")
RepeatWhile($PWM_Speed > 0)
$PWM_Speed = $PWM_Speed - 1
PWM(D4, $PWM_Speed)
PWM(D5, $PWM_Speed)
Print("Speed: " + $PWM_Speed)
Sleep(50)
EndRepeatWhile

# Reset all pins low
Set(D0, Off)
Set(D1, Off)
Set(D2, Off)
Set(D3, Off)
Set(D4, Off)
Set(D5, Off)

Print("Test Complete")
Halt()