Also, the "default code" that comes from IFI contains a few lines of code that copy values from the joystick ports (connected to the Operator Interface) to the PWM outputs. PWM outputs are wired to Victor speed controllers, and these to the motors.
In user_routines.c is the "Default_Routine()" function where most people do their programming. The following lines copy joystick values to the PWM outputs. 127 is the 'neutral' or 'stop' value for the Victor speed controllers ... sending the PWM a 0 value would operate the attached motor at full speed, sending 254 would operated at full speed in the opposite direction.
Code:
p1_x = 255 - p1_y;
p1_y = 255 - pwm05;
pwm13 = pwm14 = Limit_Mix(2000 + p1_y + p1_x - 127);
pwm15 = pwm16 = Limit_Mix(2000 + p1_y - p1_x + 127);
In ifi_aliases.h you find the definitions for the p1_x, p1_y, etc, etc defined-constants:
Code:
#define p1_y rxdata.oi_analog01
#define p2_y rxdata.oi_analog02
#define p3_y rxdata.oi_analog03
#define p4_y rxdata.oi_analog04
#define p1_x rxdata.oi_analog05
#define p2_x rxdata.oi_analog06
#define p3_x rxdata.oi_analog07
#define p4_x rxdata.oi_analog08
#define p1_wheel rxdata.oi_analog09
#define p2_wheel rxdata.oi_analog10
#define p3_wheel rxdata.oi_analog11
#define p4_wheel rxdata.oi_analog12
#define p1_aux rxdata.oi_analog13
#define p2_aux rxdata.oi_analog14
#define p3_aux rxdata.oi_analog15
#define p4_aux rxdata.oi_analog16