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AVR_Learning/Make AVR Examples/Chapter10_Pulse-Width-Modulation/pwm_cross-fading_cylons/cross-fading_cylons.c

61 lines
1.4 KiB
C

/*
Cross-fading Cylon Eyes
A PWM demo
*/
// ------- Preamble -------- //
#include <avr/io.h> /* Defines pins, ports, etc */
#include <util/delay.h> /* Functions to waste time */
#include "pinDefines.h"
int main(void) {
uint8_t thisEye = 0;
uint8_t nextEye = 1;
uint8_t brightness = 0;
int8_t direction = 1;
uint8_t i;
// -------- Inits --------- //
// Init all LEDs
LED_DDR = 0xff;
SPEAKER_DDR |= (1 << SPEAKER);
// ------ Event loop ------ //
while (1) {
// PWM
for (brightness = 0; brightness < 255; brightness++) {
for (i = 0; i < 255; i++) {
if (i < brightness) {
LED_PORT &= ~(1 << thisEye); /* dimming */
LED_PORT |= (1 << nextEye); /* getting brighter */
}
else {
LED_PORT |= (1 << thisEye);
LED_PORT &= ~(1 << nextEye);
}
LED_PORT &= ~(1 << thisEye); /* make sure it's off */
}
}
// Cylon Scan
thisEye += direction; /* move on to next eye */
if (thisEye == 0) {
direction = 1;
}
if (thisEye == 7) {
direction = -1;
}
nextEye = thisEye + direction;
} /* End event loop */
return 0; /* This line is never reached */
}