clockface.c

WWVB receiver using AVR.

/* $Id: clockface.c,v 1.15 2005/10/30 19:44:38 simimeie Exp $
 * Functions for controlling the "clock face", which consists of 60 LEDs
 * (12 big, 48 smaller) that are controlled by a MAX 7219 and show the
 * seconds like an analog clock.
 */

#define BV _BV
#include <avr/io.h>
#include "clockface.h" 

/* Connected to PB2 - PB4 on our mainboard */
#define CFPORT PORTB
#define CFDDR DDRB
#define DINPIN PB4
#define CLKPIN PB2
#define LOADPIN PB3

uint8_t clockface_status;
uint8_t clockface_lastval;
uint8_t clockface_brightness;

void clockface_init(void) {
	CFDDR |= BV(DINPIN);
	CFDDR |= BV(CLKPIN);
	CFDDR |= BV(LOADPIN);
	sendmax7219command(0x0C, 0x00); /* Shutdown */
}

void sendmax7219command(uint8_t address, uint8_t data) {
	uint8_t i;
	for (i = 0; i < 4; i++) {
		if (address & 0x08) {
			CFPORT |= BV(DINPIN);
		} else {
			CFPORT &= (uint8_t)~BV(DINPIN);
		}
		CFPORT |= BV(CLKPIN);
		CFPORT &= (uint8_t)~BV(CLKPIN);
		address <<= 1;
	}
	for (i = 0; i < 8; i++) {
		if (data & 0x80) {
			CFPORT |= BV(DINPIN);
		} else {
			CFPORT &= (uint8_t)~BV(DINPIN);
		}
		CFPORT |= BV(CLKPIN);
		CFPORT &= (uint8_t)~BV(CLKPIN);
		data <<= 1;
	}
	CFPORT &= (uint8_t)~BV(DINPIN);
	CFPORT |= BV(LOADPIN);
	CFPORT &= (uint8_t)~BV(LOADPIN);
}

void clockface_update(uint8_t mode, uint8_t seconds) {
	uint8_t i;
	if ((seconds == 0) && (mode == 2)) {
		seconds = 60;
	}
	for (i=1; i<=8; i++) {
		uint8_t j;
		if (mode == 2) {
			/* Only the current second LED is on */
			j = (0x11 << (seconds & 3));
		} else {
			if (seconds <= 8) {
				if (seconds == 8) {
					j = 0xff;
				} else if (seconds == 0) {
					j = 0x00;
				} else {
					j = ((0xFF >> (8-seconds)) << (8-seconds));
				}
				seconds = 8;
			} else {
				j = 0xff;
			}
			if (mode == 1) {
				j = (uint8_t)~j;
			}
		}
		seconds -= 8;
		sendmax7219command(i, j);
	}
	sendmax7219command(0x09, 0x00); /* No decode mode */
	sendmax7219command(0x0F, 0x00); /* Disable digit test mode */
	sendmax7219command(0x0B, 0x07); /* Scan Limit (all digits on) */
	if (clockface_brightness) {
		sendmax7219command(0x0A, clockface_brightness); /* Intensity */
		sendmax7219command(0x0C, 0x01); /* Disable shutdown mode */
	} else {
		sendmax7219command(0x0C, 0x00); /* Shutdown */
	}
}