Overview | Main | State Machine | Events | IR | Tape | Drivetrain | PWM | Flash | Two Minute Timer | Bump
void drivetrainInit(void): initialize the drivetrain subsystem
void commandMotion(char cmd): send a new movement command to the drive wheels
void main(void): test harness for the drivetrain module
The drivetrain module provides a public function to accept and execute movement commands from other modules. The available commands are rotate counter-clockwise, rotate clockwise, drive forward, drive in reverse, and stop. Each movement command has two available speeds, fast and slow. The module uses two PWM pins for PWM and two output pins for direction control.
PSEUDOCODE
(Download Pseudocode .doc 27kb)
void drivetrainInit(void)
Initialize the PWM module
Initialize the PWM channels used by the motors
Set the data direction of the pins used for direction control to be outputs
Make sure the robot starts stopped
void commandMotion(char cmd)
Stop is both wheels at 0% duty cycle
CCW fast is left backward fast and right forward fast
CCW slow is left backward slow and right forward slow
CW fast is left forward fast and right backward fast
CW slow is left forward slow and right backward slow
Forward fast is both wheels forward fast
Forward slow is both wheels forward slow
Backward fast is both wheels backward fast
Backward slow is both wheels backward slow
void main(void) **Test Harness**
Initialize the terminal I/O subsystem
Initialize the drivetrain module
Repeat forever
Get a character from the keyboard
If the character is ‘w’
Drive forward fast
Else if the character is ‘a’
Rotate counter-clockwise fast
Else if the character is ‘s’
Drive reverse fast
Else if the character is ‘d’
Rotate clockwise fast
Else if the character is ‘x’
Stop
Else if the character is ‘i’
Drive forward slow
Else if the character is ‘j’
Rotate counter-clockwise slow
Else if the character is ‘k’
Drive reverse slow
Else if the character is ‘l’
Rotate clockwise slow
Else if the character is ‘m’
Stop
Else
Complain about an invalid character
Stop