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gc_n64_usb-v3/intervaltimer2.c

46 lines
1.2 KiB
C

/* gc_n64_usb : Gamecube or N64 controller to USB firmware
Copyright (C) 2007-2016 Raphael Assenat <raph@raphnet.net>
This program 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.
This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <avr/io.h>
#include "intervaltimer2.h"
void intervaltimer2_init(void)
{
TCCR0A = (1<<WGM01);
TCCR0B = (1<<CS02) | (1<<CS00); // CTC, /1024 prescaler
}
void intervaltimer2_set16ms(void)
{
int interval_ms = 16;
// Maximum 16ms. 17ms overflows the 8-bit OCR0A register (value of 265)
// 16ms: 250
TCNT0 = 0;
OCR0A = interval_ms * (F_CPU/1024) / 1000;
}
char intervaltimer2_get(void)
{
if (TIFR0 & (1<<OCF0A)) {
TIFR0 = 1<<OCF0A;
return 1;
}
return 0;
}