/********************************************************************
* *
* Project: Channel Selector *
* Source: Channel_Selector_v1.c *
* Author: Mike McLaren, K8LH *
* Date: 16-Feb-10 *
* Revised: 16-Feb-10 *
* *
* OEM 16F886 2-Digit 01-99 Channel Selector *
* *
* *
* IDE: MPLAB 8.14 (tabs = 4) *
* Lang: SourceBoost BoostC v6.95, Lite/Free version *
* *
* *
********************************************************************/
#include <system.h>
#pragma DATA _CONFIG1, _LVP_OFF & _MCLRE_OFF & _WDT_OFF & _INTOSCIO
#pragma DATA _CONFIG2, _BOR40V
//--< function prototypes >------------------------------------------
//--< typedef and defines >------------------------------------------
typedef unsigned char u08;
typedef unsigned int u16;
#define r08 const rom unsigned char
#define upswitch flags.7 // debounced "up" switch flag
#define dnswitch flags.6 // debounced "dn" switch flag
#define polarity flags.0 // eprom "polarity" jumper
//--< variables >----------------------------------------------------
u08 swnew = 0; // switch sample var'
u08 swold = 0; // switch state latch
u08 flags = 0; // switch press flags
u08 channel = 1; // packed BCD channel, 0x01..0x99
r08 segdata[] = { 0b00111111, // "0" -|-|F|E|D|C|B|A
0b00000110, // "1" -|-|-|-|-|C|B|-
0b01011011, // "2" -|G|-|E|D|-|B|A
0b01001111, // "3" -|G|-|-|D|C|B|A
0b01100110, // "4" -|G|F|-|-|C|B|-
0b01101101, // "5" -|G|F|-|D|C|-|A
0b01111101, // "6" -|G|F|E|D|C|-|A
0b00000111, // "7" -|-|-|-|-|C|B|A
0b01111111, // "8" -|G|F|E|D|C|B|A
0b01101111 }; // "9" -|G|F|-|D|C|B|A
//--< main >---------------------------------------------------------
void main()
{
ansel = 0; // ANS0..ANS7 ADC inputs off
anselh = 0; // ANS8..ANS13 ADC inputs off
osccon = 0b01110000; // set INTOSC to 8 MHz
while(!osccon.HTS); // wait 'til oscillator stable
trisc = 0b00000000; // set all PORTC pins to outputs
trisb = 0b00000000; // set all PORTB pins to outputs
trisa = 0b11000001; // RA7, RA6, and RA1 = inputs
porta = 0b00000000; // set all output latches to '0'
portb = 0b00000000; // set all output latches to '0'
porta = 0b00000000; // set all output latches to '0'
// setup Timer 2 for 8 msec interrupts (8 MHz clock)
tmr2 = 0; // clear Timer 2 register
t2con = 0b00011110; // '0-------' unimplemented bit
// '-0011---' TOUTPS<3:0>, postscale 4
// '-----1--' TMR2ON, turn Timer 2 on
// '------10' T2CKPS<1:0>, prescale 16
pr2 = 250-1; // 250 x 32-usec 'ticks' = 8 msecs
pir1 = 0; // clear peripheral interrupt flags
pie1.TMR2IE = 1; // set Timer 2 interrupt enable bit
intcon = 0b11000000; // '1-------' GIE, enable global ints
// '-1------' PEIE, enable peripheral ints
// '--0-----' T0IE, TMR0 ints disabled
// '---0----' INTE, off
// '----0---' GPIE, IOC disabled
// '-----000' T0IF/INTF/GPIF flags
// main program loop
while(1)
{ if(upswitch) // if "up" switch pulse
{ upswitch = 0; // clear the switch flag and
if(channel < 0x99) // if less than upper limit 0x99
{ asm // do packed BCD increment
{ movf _channel,W ;
addlw 7 ; bcd increment + bcd adjust
btfss _status,DC ; adjust required, yes, skip, else
addlw 0xFA ; undo adjust (add -6)
movwf _channel ; update "channel" var'
} //
} //
}
if(dnswitch) // if "dn" switch pulse
{ dnswitch = 0; // clear the switch flag and
if(channel > 0x01) // if greater than lower limit 0x01
{ asm // do packed BCD decrement
{ movf _channel,W ;
addlw 0xFF ; bcd decrement
btfss _status,DC ; bcd adjust required? no, skip, else
addlw 0xFA ; do bcd adjust (add -6)
movwf _channel ; update "channel" var'
} //
} //
}
if(polarity) // if polarity jumper off (hi)
portc = channel; // normal eprom address data
else // if polarity jumper on (lo)
portc = ~channel; // invert eprom address data
}
}
/********************************************************************
* ISR - refresh display and switch flags (62.5 Hz refresh rate) *
********************************************************************/
void interrupt() // 8-msec timer 2 interrupts
{ u08 index; // isr work variable
pir1.TMR2IF = 0; // clear timer 2 interrupt flag
portb &= 0x80; // blank the display
portb ^= 0x80; // toggle digit select pin (RB7)
if(portb.7) // if 'tens' digit selected
index = channel >> 4; // use upper nybble as index
else // if 'ones' digit selected
index = channel & 15; // use lower nybble as index
portb |= segdata[index]; // display new digit
swnew = ~porta; // sample active low switches
swnew &= 0b11000001; // on RA7, RA6, and RA0 pins
swnew ^= swold; // changes, hi or lo
swold ^= swnew; // update switch state latch
swnew &= swold; // filter out "new lo" bits
flags |= swnew; // save "new hi" flag bits
}
