/************************************************************************
* *
* Filename: BC_L5-Count_7seg_x3-HTC.c *
* Date: 8/8/12 *
* File Version: 1.5 *
* *
* Author: David Meiklejohn *
* Company: Gooligum Electronics *
* *
*************************************************************************
* *
* Architecture: Baseline PIC *
* Processor: 16F506 *
* Compiler: MPLAB XC8 v1.01 (Free mode) *
* *
*************************************************************************
* *
* Files required: none *
* *
*************************************************************************
* *
* Description: Lesson 5, example 2 *
* *
* Demonstrates use of multiplexing to drive multiple 7-seg displays *
* *
* 3-digit 7-segment LED display: 1 digit minutes, 2 digit seconds *
* counts in seconds 0:00 to 9:59 then repeats, *
* with timing derived from int 4 MHz oscillator *
* *
*************************************************************************
* *
* Pin assignments: *
* RB0-1,RB4,RC1-4 = 7-segment display bus (common cathode) *
* RC5 = minutes enable (active high) *
* RB5 = tens enable *
* RC0 = ones enable *
* *
************************************************************************/
#include <xc.h>
#include <stdint.h>
/***** CONFIGURATION *****/
// ext reset, no code protect, no watchdog, 4 MHz int clock
//__CONFIG(MCLRE_ON & CP_OFF & WDT_OFF & IOSCFS_OFF & OSC_IntRC_RB4EN);
// CONFIG
#pragma config FOSC = XT // Oscillator Selection bits (XT oscillator)
#pragma config WDTE = OFF // Watchdog Timer Enable bit (WDT disabled)
#pragma config PWRTE = OFF // Power-up Timer Enable bit (PWRT disabled)
#pragma config BOREN = OFF // Brown-out Reset Enable bit (BOR disabled)
#pragma config LVP = OFF // Low-Voltage (Single-Supply) In-Circuit Serial Programming Enable bit (RB3 is digital I/O, HV on MCLR must be used for programming)
#pragma config CPD = OFF // Data EEPROM Memory Code Protection bit (Data EEPROM code protection off)
#pragma config WRT = OFF // Flash Program Memory Write Enable bits (Write protection off; all program memory may be written to by EECON control)
#pragma config CP = OFF // Flash Program Memory Code Protection bit (Code protection off)
// Pin assignments
#define HOURS PORTBbits.RB4
#define MINUTES PORTBbits.RB5 // minutes enable
#define TENS PORTBbits.RB6 // tens enable
#define ONES PORTBbits.RB7 // ones enable
/***** PROTOTYPES *****/
void set7seg(uint8_t digit); // display digit on 7-segment display
/***** MACROS *****/
#define TMR0_2 (TMR0 & 1<<2) // access to TMR0<2>
/***** MAIN PROGRAM *****/
void main()
{
uint8_t mpx_cnt; // multiplex counter
uint8_t mins, secs; // time counters
//*** Initialisation
// configure ports
TRISB = 0; // configure PORTB and PORTC as all outputs
TRISC = 0;
ADCON0 = 0; // disable AN0, AN1, AN2 inputs
// CM1CON0bits.C1ON = 0; // and comparator 1 -> RB0,RB1 digital
// CM2CON0bits.C2ON = 0; // disable comparator 2 -> RC1 digital
// configure timer
OPTION_REG = 0b11010111; // configure Timer0:
//--0----- timer mode (T0CS = 0) -> RC5 usable
//----0--- prescaler assigned to Timer0 (PSA = 0)
//-----111 prescale = 256 (PS = 111)
// -> increment every 256 us
// (TMR0<2> cycles every 2.048 ms)
//*** Main loop
for (;;)
{
// count in seconds from 0:00 to 9:59
for (mins = 0; mins < 10; mins++)
{
for (secs = 0; secs < 60; secs++)
{
// for each time count, multiplex display for 1 second
// (display each of 3 digits for 2.048 ms each,
// so repeat 1000000/2048/3 times to make 1 second)
for (mpx_cnt = 0; mpx_cnt < 1000000/2048/3; mpx_cnt++)
{
// display minutes for 2.048 ms
while (!TMR0_2) // wait for TMR0<2> to go high
;
set7seg(mins); // output minutes digit
MINUTES = 1; // enable minutes display
while (TMR0_2) // wait for TMR0<2> to go low
;
// display tens for 2.048 ms
while (!TMR0_2) // wait for TMR0<2> to go high
;
set7seg(secs/10); // output tens digit
TENS = 1; // enable tens display
while (TMR0_2) // wait for TMR0<2> to go low
;
// display ones for 2.048 ms
while (!TMR0_2) // wait for TMR0<2> to go high
;
set7seg(secs%10); // output ones digit
ONES = 1; // enable ones display
while (TMR0_2) // wait for TMR0<2> to go low
;
}
}
}
}
}
/***** FUNCTIONS *****/
/***** Display digit on 7-segment display *****/
void set7seg(uint8_t digit)
{
// pattern table for 7 segment display on port B
const uint8_t pat7segC[10] = {
// RB4 = E, RB1:0 = FG
0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x67
// 0b010010, // 0
// 0b000000, // 1
// 0b010001, // 2
// 0b000001, // 3
// 0b000011, // 4
// 0b000011, // 5
// 0b010011, // 6
// 0b000000, // 7
// 0b010011, // 8
// 0b000011 // 9
};
// pattern table for 7 segment display on port C
//const uint8_t pat7segC[10] = {
// RC4:1 = CDBA
// 0b011110, // 0
// 0b010100, // 1
// 0b001110, // 2
// 0b011110, // 3
// 0b010100, // 4
// 0b011010, // 5
// 0b011010, // 6
// 0b010110, // 7
// 0b011110, // 8
// 0b011110 // 9
//};
// Disable displays
PORTB = 0; // clear all digit enable lines on PORTB
// PORTC = 0; // and PORTC
// Output digit pattern
PORTC = pat7segC[digit]; // lookup and output port B and C patterns
//PORTC = pat7segC[digit];
}