///////////////////////////////////////////////////////////////////////// //// main01.c //// //// //// //// Copyright 2007 by James K Beard and Rowan University. //// //// //// //// This program reads two A to D converters and uses them as //// //// inputs for two PWM outputs. Two pushbuttons are used to //// //// toggle outputs of the PWM between I/O pins, so that motor //// //// direction can be reversed. An additional pushbutton is passed //// //// through to an I/O pin as a magnet driver. //// //// //// //// I/O Pins: //// //// Pin No. Function //// //// A0 2 INPUT Speed thumbwheel input //// //// A1 3 INPUT Lift thumbwheel input //// //// B1 22 INPUT Auxiliary pushbutton, 0 => down //// //// B2 23 INPUT Auxiliary toggle, intially 0 //// //// C0 11 OUTPUT Lifft up-down, 0 => down (initially down) //// //// C1 12 OUTPUT Lift PWM output //// //// C2 13 OUTPUT Propulsion PWM output //// //// C3 14 OUTPUT Propulsion fwd-bk, 0 => backw (init. fwd.) //// //// C4 15 OUTPUT Magnet drive, 0 => off (initially off) //// //// C5 16 INPUT Magnet toggle, 0 => down (initially off) //// //// C6 17 INPUT Lift toggle, 0 => down (initially off) //// //// C7 18 INPUT Propulsion drctn toggle 0 => dwn (init off) //// //// //// //// April 5, 2007: deleted output to bus B, added delay in loop //// //// and added a fourth pushbutton on bus B1, output on B2 //// ///////////////////////////////////////////////////////////////////////// #include <16F876A.h> #fuses HS,NOWDT,NOPROTECT,NOLVP #device ADC=10 //10 bits right justified in a 16 bit word #use delay(clock=4000000) //Put your clock rate here; 4 MHz == 4000000 //#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7) //RS-232 not used #define scale_shift 4 //log2(T2_Ticks/2^(ADC bits)); see below #define speedpos 0 //Propulsion is bottom 4 bits #define liftpos 4 //Lift is top 4 bits void main() { long int speed, lift, adc_out; //long int is 16 bits in CCS PIC C MCU compiler int lsb;//speed_Hbridge, lift_Hbridge, Hbridge, lsb; //8 bits short forward, lift_up, magnet_on, aux_function; //One bit short pbp, pbp_state, pbl, pbl_state, pbm, pbm_state, pbx, pbx_state; //Anti-bounce logic //SETUP SET_TRIS_B(0b00000010); //All outputs except pushbutton on B1; use only output on B2 SET_TRIS_C(0b11100000); //Buttons input on C7, C6, C5, magnet drive on C4 // setup_port_a( ALL_ANALOG ); //Inputs are A0 A1 A2 A3 A5, ref is 5 V setup_adc_ports( ALL_ANALOG ); //Inputs are A0 A1 A2 A3 A5, ref is 5 V setup_adc( ADC_CLOCK_INTERNAL ); //Internal clock, or box crystal if there //Set up PWM clock, which is always timer 2 //Minimum Frequency: //The resolution is the number of ticks in a PWM period, and we want 10 bits //A period is 1/(PWM frequency) //The number of ticks in Timer 2 is // T2_Ticks = 4*T2_DIV*(period+1) //We will use a period (second counter) of 255 //T2_DIV can be 1, 4 or 16 //This gives us 1024 (10 bits), 4096 (12 bits), or 16385 (14 bits) //PWM frequency determination //PWM frequency is divided down from master clock // PWM frequency = Clock/T2_Ticks) //We have a 4 MHz clock. //This gives us a choice of 3906 Hz, 977 Hz or 244 Hz //We will try 244 Hz. If it is too low and motor buzzes, try 977 Hz setup_timer_2(T2_DIV_BY_16, 255, 1); //The ADC output must be scaled so that 2^10=1024 is scaled to the PWM period //See "#define scale_shift 4" above setup_ccp1(CCP_PWM); //Configure CCP1 as a PWM setup_ccp2(CCP_PWM); //Configure CCP2 as a PWM //VARIABLE INITIALIZATIONS pbp=1; //Initialize all pushbuttons as off, with pullups pbl=1; pbm=1; pbx=1; pbp_state=1; pbl_state=1; pbm_state=1; pbx_state=1; forward=1; //Initially, move forward lift_up=0; //Initially, hook moves down magnet_on=0; //Initially, magnet is off aux_function=0; //Initially, auxiliary function is off do { //Read speed thumbwheel set_adc_channel(0); //Propulsion thumbwheel is port A0 delay_us(10); //A small delay is required before a read adc_out=Read_ADC(); lsb=bit_test(adc_out,0); //Extend LSB on scaling shift speed = ((adc_out+lsb)<