/*
* File: main.c
* Author: dan1138
* Compiler: XC8 V2.32
* IDE: MPLABX v5.50
*
* Created on July 26, 2021, 3:26 PM
*
* PIC18F4550
* +----------:_:----------+
* VPP -> 1 : RE3/MCLR/VPP PGD/RB7 : 40 <> DIGIT0/PGD
* <> 2 : RA0/AN0 PGC/RB6 : 39 <> DIGIT1/PGC
* <> 3 : RA1/AN1 PGM/RB5 : 38 <> DIGIT2
* <> 4 : RA2/AN2 AN11/RB4 : 37 <> DIGIT3
* <> 5 : RA3/AN3 AN9/RB3 : 36 <> DIGIT4
* <> 6 : RA4 INT2/AN8/RB2 : 35 <> DIGIT5
* <> 7 : RA5/AN4 INT1/AN10/RB1 : 34 <>
* <> 8 : RE0/AN5 INT0/AN12/RB0 : 33 <>
* <> 9 : RE1/AN6 VDD : 32 <- 5v0
* <> 10 : RE2/AN7 VSS : 31 <- GND
* 5v0 -> 11 : VDD RD7 : 30 <> SEGdp
* GND -> 12 : VSS RD6 : 29 <> SEGg
* <> 13 : OSC1 RD5 : 28 <> SEGf
* <> 14 : OSC2 RD4 : 27 <> SEGe
* <> 15 : RC0 RX/RC7 : 26 <>
* <> 16 : RC1/CCP2 TX/RC6 : 25 <>
* <> 17 : RC2/CCP1 D+/RC5 : 24 <- (can only be used as GPIO input)
* <> 18 : RC3 D-/RC4 : 23 <- (can only be used as GPIO input)
* SEGa <> 19 : RD0 RD3 : 22 <> SEGd
* SEGb <> 20 : RD1 RD2 : 21 <> SEGc
* +-----------------------:
* DIP-40
*
* Description:
*
* Homework assignment see EDA board:
* https://www.edaboard.com/threads/ds1307-slows-with-7-segment-display.398985/
*
* This is an application to show how to use the TIMER0 interrupt to
* refresh a multiplexed six digit 7-segment LED display matrix.
*/
#pragma config PLLDIV = 1, CPUDIV = OSC1_PLL2, USBDIV = 1
#pragma config FOSC = INTOSC_XT, FCMEN = OFF, IESO = OFF
#pragma config PWRT = OFF, BOR = OFF, BORV = 3, VREGEN = OFF
#pragma config WDT = OFF, WDTPS = 32768, CCP2MX = ON
#pragma config PBADEN = ON, LPT1OSC = OFF, MCLRE = ON
#pragma config STVREN = ON, LVP = OFF, ICPRT = OFF, XINST = OFF
#pragma config CP0 = OFF, CP1 = OFF, CP2 = OFF, CP3 = OFF
#pragma config CPB = OFF, CPD = OFF
#pragma config WRT0 = OFF, WRT1 = OFF, WRT2 = OFF, WRT3 = OFF
#pragma config WRTC = OFF, WRTB = OFF, WRTD = OFF
#pragma config EBTR0 = OFF, EBTR1 = OFF, EBTR2 = OFF, EBTR3 = OFF
#pragma config EBTRB = OFF
#include <xc.h>
#define _XTAL_FREQ (8000000ul)
/*
* Common cathode LED segment drivers for hexadecimal digits
*/
const char LEDDigit[] =
{
/* gfedcba _ */
0b00111111, /* | | */
/* |_| */
/* */
0b00000110, /* | */
/* | */
/* _ */
0b01011011, /* _| */
/* |_ */
/* _ */
0b01001111, /* _| */
/* _| */
/* */
0b01100110, /* |_| */
/* | */
/* _ */
0b01101101, /* |_ */
/* _| */
/* _ */
0b01111101, /* |_ */
/* |_| */
/* _ */
0b00000111, /* | */
/* | */
/* _ */
0b01111111, /* |_| */
/* |_| */
/* _ */
0b01100111, /* |_| */
/* | */
/* _ */
0b01110111, /* |_| */
/* | | */
/* */
0b01111100, /* |_ */
/* |_| */
/* _ */
0b00111001, /* | */
/* |_ */
/* */
0b01011110, /* _| */
/* |_| */
/* _ */
0b01111001, /* |_ */
/* |_ */
/* _ */
0b01110001, /* |_ */
/* | */
/* */
0b00000000, /* blank */
/* */
};
volatile unsigned char DigitSegments[6];
volatile unsigned char DigitSelected;
/*
* Interrupt Service Routines
*/
void __interrupt(high_priority) ISR_hi(void)
{
if((INTCONbits.T0IE) && (INTCONbits.T0IF)) /* TIMER0 asserts and interrupt every 1.024 milliseconds */
{
/*
* Turn on one of six digits in the LED display matrix
*/
INTCONbits.T0IF = 0;
LATB |= 0b11111100; /* Turn off all digit drivers */
if(DigitSelected >= sizeof(DigitSegments)) DigitSelected = 0;
LATD = DigitSegments[DigitSelected];
LATB &= ~(0x80>>DigitSelected);
DigitSelected++;
}
}
/*
* Convert unsigned long to 6 decimal digits for the LED display
*/
void LED_ulToSegments(unsigned long data)
{
unsigned char Digit;
Digit = sizeof(DigitSegments);
do
{
Digit--;
DigitSegments[Digit] = LEDDigit[data % 10];
data /= 10;
} while(Digit);
}
/*
* Make LED display blank
*/
void LED_blank(void)
{
unsigned char Digit;
Digit = sizeof(DigitSegments);
do
{
DigitSegments[--Digit] = 0;
} while(Digit);
}
/*
* Main application
*/
void main(void)
{
unsigned long Count;
INTCONbits.GIEH = 0; /* disable all interrupt sources */
INTCONbits.GIEL = 0;
INTCONbits.INT0IE = 0;
INTCONbits.RBIE = 0;
INTCONbits.TMR0IE = 0;
INTCON3bits.INT1IE = 0;
INTCON3bits.INT2IE = 0;
PIE1 = 0;
PIE2 = 0;
RCONbits.IPEN = 0; /* Use legacy interrupt mode */
/*
* Select 8 MHz internal oscillator
*/
OSCCON = 0x72;
/*
* Make all GPIOs digital
*/
ADCON1 = 0x0F; /* Disable all ADC analog inputs */
CMCON = 0x07; /* Disable all Comparator analog inputs */
/*
* Setup LED multiplexer
*/
INTCONbits.TMR0IE = 0;
TRISD = 0; /* Make segment drivers outputs */
TRISB &= 0b00000011; /* Make digit drivers outputs */
DigitSelected = 0;
LED_blank();
T0CON = 0b01000010; /* TIMER0 off, FOSC/4 clock, prescale 1:8 */
INTCON2bits.T0IP = 1; /* Select high priority interrupt handler */
TMR0 = 0;
INTCONbits.TMR0IF = 0;
INTCONbits.TMR0IE = 1;
T0CONbits.TMR0ON = 1; /* Turn on TIMER0 */
/*
* Enable system interrupts
*/
INTCONbits.GIEL = 1;
INTCONbits.GIEH = 1;
/*
* Process loop
*/
Count = 0;
for(;;)
{
__delay_ms(1000);
LED_ulToSegments(Count++);
}
}