Potentiometer with ADC

[Ken Streeter]

Originally Posted by Shinigami2057

I have a dumb question - I Just hooked up a 100K pot to analog input 01, but Get_Analog_Value(rc_ana_in01) is only returning values from 0-9, and it definitely is not linear. This is the (very simple) code we're using just to test:

printf("%u\n", Get_Analog_Value(rc_ana_in01));

Am I missing something important here? Is there something wrong with the pot? (It's wired correctly)

Thanks

The problem is that Get_Analog_Value returns a 10-bit value, rather than an 8-bit value. In general, we discarded the lowest 2 bits of the potentiometer value as "noise" and just used the top 8 bits via the following code:

 int Get_Robot_Pot(void) {
    unsigned char robot_pot_8bits;
 
    // analog inputs on the robot are returned as 10 bit values, the line below
    // drops off the bottom two bits to give a one-byte value for the elevation
    robot_pot_8bits = (unsigned char) (Get_Analog_Value( rc_ana_in01 ) >> 2);
    printf("Pot Value: %3d\r\n", (int) robot_pot_8bits);
    return ((int) robot_pot_8bits);
 }