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/*
atmega48_ledramp.c
Copyright 2008, 2009 Michel Pollet <buserror@gmail.com>
This file is part of simavr.
simavr is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
simavr is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with simavr. If not, see <http://www.gnu.org/licenses/>.
*/
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/sleep.h>
// for linker, emulator, and programmer's sake
#include "avr_mcu_section.h"
AVR_MCU(F_CPU, "atmega48");
#include <stdio.h>
/* ------------------------------------------------------------------------- */
static int uart_putchar(char c, FILE *stream) {
if (c == '\n')
uart_putchar('\r', stream);
loop_until_bit_is_set(UCSR0A, UDRE0);
UDR0 = c;
return 0;
}
static FILE mystdout = FDEV_SETUP_STREAM(uart_putchar, NULL,
_FDEV_SETUP_WRITE);
#define TICK_HZ 64
volatile uint32_t tickCount;
ISR(TIMER2_COMPA_vect) // handler for Output Compare 1 overflow interrupt
{
sei();
tickCount++;
}
void tick_init()
{
/*
Timer 2 as RTC
*/
// needs to do that before changing the timer registers
// ASYNC timer using a 32k crystal
ASSR |= (1 << AS2);
TCCR2A = (1 << WGM21);
// use CLK/8 prescale value, clear timer/counter on compareA match
TCCR2B = (2 << CS20);
/* -- MathPad
clock=32768
prescaler=8
hz=64
(clock/prescaler/hz)-1:63 -- */
OCR2A = 63;
TIMSK2 |= (1 << OCIE2A);
}
volatile uint8_t pressed = 0;
ISR(PCINT1_vect)
{
pressed = (PINC & (1 << PC0)) ? 0 : 1;
// wouldn't do that on real hardware, but it's a demo...
printf("PCINT1_vect %02x\n", PINC);
}
int main()
{
DDRB=0xff; // all PORT B output
DDRC = 0; // make PORT C input
// enable pin change interrupt for PORT C pin 0
PCMSK1 |= (1 << PCINT8); // C0
PCICR |= (1 << PCIE1);
stdout = &mystdout;
tick_init();
sei();
uint8_t mask = 0;
for (;;) {
mask <<= 1;
if (!mask)
mask = 1;
if (pressed)
PORTB = 0xff;
else
PORTB = mask;
sleep_mode();
}
}
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