The CCS C compiler includes a library of example programs for many common applications. Each example program contains a header with instructions on how to run the example, and if necessary, the wiring instructions for interfacing external devices.
Here are three such example programs included with our compiler, as well as a list file generated by the compiler which shows the assembly generated to correspond with the C code.
For a full list of example files and source code drivers included with the CCS C compiler go here
Jump to: Stepper Motor Controller | Seconds Timer | Simple A/D | Example List File | List of Example Files
Stepper Motor Controller
/////////////////////////////////////////////////////////////////////////
//// EX_STEP.C ////
//// ////
//// This program interfaces to a stepper motor. The program will ////
//// use the RS-232 interface to either control the motor with a ////
//// analog input, a switch input or by RS-232 command. ////
//// ////
//// Configure the CCS prototype card as follows: ////
//// Connect stepper motor to pins 47-50 (B0-B3) ////
//// Conenct 40 to 54 (pushbutton) ////
//// Connect 9 to 15 (pot) ////
//// See additional connections below. ////
/////////////////////////////////////////////////////////////////////////
//// (C) Copyright 1996,2001 Custom Computer Services ////
//// This source code may only be used by licensed users of the CCS ////
//// C compiler. This source code may only be distributed to other ////
//// licensed users of the CCS C compiler. No other use, ////
//// reproduction or distribution is permitted without written ////
//// permission. Derivative programs created using this software ////
//// in object code form are not restricted in any way. ////
/////////////////////////////////////////////////////////////////////////
byte const POSITIONS[4] = {0b0101,
0b1001,
0b1010,
0b0110};
byte const POSITIONS[8] = {0b0101,
0b0001,
0b1001,
0b1000,
0b1010,
0b0010,
0b0110,
0b0100};
drive_stepper(byte speed, char dir, byte steps) {
static byte stepper_state = 0;
byte i;
for(i=0;i delay_ms(speed);
set_tris_b(0xf0);
port_b = POSITIONS[ stepper_state ];
if(dir!=’R’)
stepper_state=(stepper_state+1)&(sizeof(POSITIONS)-1);
else
stepper_state=(stepper_state-1)&(sizeof(POSITIONS)-1);
}
}
use_pot() {
byte value;
setup_adc(adc_clock_internal);
set_adc_channel( 1 );
printf(“\r\n”);
while( TRUE ) {
value=read_adc();
printf(“%2X\r”,value);
if(value<0x80)
drive_stepper(value,'R',8);
else if(value>0x80)
drive_stepper(128-(value-128),’F’,8);
}
}
use_switch(byte speed, char dir) {
byte steps;
printf(“\n\rSteps per press: “);
steps = gethex();
while(true) {
while(input(PIN_B7)) ;
drive_stepper(speed,dir,steps);
while(!input(PIN_B7)) ;
delay_ms(100);
}
}
main() {
byte speed,steps;
char dir;
setup_port_a(RA0_RA1_ANALOG);
while (TRUE) {
printf(“\n\rSpeed (hex): “);
speed = gethex();
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if(speed==0)
use_pot();
printf("\n\rDirection (F,R): ");
dir=getc()|0x20;
putc(dir);
printf("\n\rSteps (hex): ");
steps = gethex();
if(steps==0)
use_switch(speed,dir);
drive_stepper(speed,dir,steps);
}
}
Seconds Timer
///////////////////////////////////////////////////////////////////////
//// EX_STWT.C ////
//// ////
//// This program uses the RTCC (timer0) and interrupts to keep a ////
//// real time seconds counter. A simple stop watch function is ////
//// then implemented. ////
//// ////
//// Configure the CCS prototype card as follows: ////
//// Insert jumpers from: 11 to 17 and 12 to 18. ////
///////////////////////////////////////////////////////////////////////
byte seconds; // A running seconds counter
byte int_count; // Number of interrupts left before a
// second has elapsed
clock_isr() { // the RTCC (timer0) overflows (255->0).
// For this program this is apx 76 times
if(—int_count==0) { // per second.
++seconds;
int_count=INTS_PER_SECOND;
}
}
main() {
byte start;
int_count=INTS_PER_SECOND;
set_rtcc(0);
setup_counters( RTCC_INTERNAL, RTCC_DIV_256);
enable_interrupts(RTCC_ZERO);
enable_interrupts(GLOBAL);
do {
printf("Press any key to begin.\n\r");
getc();
start=seconds;
printf("Press any key to stop.\n\r");
getc();
printf("%u seconds.\n\r",seconds-start);
} while (TRUE);
}
Simple A/D
/////////////////////////////////////////////////////////////////////////
//// EX_ADMM.C ////
//// ////
//// This program displays the min and max of 30 A/D samples over ////
//// the RS-232 interface. The process is repeated forever. ////
//// ////
//// Configure the CCS prototype card as follows: ////
//// Insert jumpers from: 11 to 17, 12 to 18 and 9 to 16 ////
//// Use the #9 POT to vary the voltage. ////
/////////////////////////////////////////////////////////////////////////
main() {
int i,value,min,max;
printf(“Sampling:”);
setup_port_a( ALL_ANALOG );
setup_adc( ADC_CLOCK_INTERNAL );
set_adc_channel( 0 );
do {
min=255;
max=0;
for(i=0;i<=30;++i) {
delay_ms(100);
value = Read_ADC();
if(value < min)
min=value;
if(value > max)
max=value;
}
printf(“\n\rMin: %2X Max: %2X\r\n”,min,max);
} while (TRUE);
}
Output Listing
……………….. min=255;
008D: MOVLW FF
008E: MOVWF 28
……………….. max=0;
008F: CLRF 29
……………….. incc=TRUE;
0090: BSF 2B,0
……………….. for(i=0;i<=30;++i) {
0091: CLRF 26
0092: MOVLW 1F
0093: SUBWF 26,W
0094: BTFSC 03,0
0095: GOTO 0AC
……………….. delay_ms(100);
0096: MOVLW 64
0097: MOVWF 2C
0098: GOTO 02D
……………….. value = Read_ADC();
0099: BSF 1F,2
009A: BTFSC 1F,2
009B: GOTO 09A
009C: MOVF 1E,W
009D: MOVWF 27
……………….. if(value < min)
009E: MOVF 28,W
009F: SUBWF 27,W
00A0: BTFSC 03,0
00A1: GOTO 0A4
……………….. min=value;
00A2: MOVF 27,W
00A3: MOVWF 28
……………….. if(value > max)
00A4: MOVF 27,W
00A5: SUBWF 29,W
00A6: BTFSC 03,0
00A7: GOTO 0AA
……………….. max=value;
00A8: MOVF 27,W
00A9: MOVWF 29
……………….. }
00AA: INCF 26,F
00AB: GOTO 092
……………….. if (incc)
00AC: BTFSC 2B,0
……………….. counter++;
00AD: INCF 2A,F