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- /* sd2snes - SD card based universal cartridge for the SNES
- Copyright (C) 2009-2010 Maximilian Rehkopf <otakon@gmx.net>
- This file was adapted from sd2iec, written by Ingo Korb.
- Original copyright header follows:
- */
- /* sd2iec - SD/MMC to Commodore serial bus interface/controller
- Copyright (C) 2007-2009 Ingo Korb <ingo@akana.de>
- Inspiration and low-level SD/MMC access based on code from MMC2IEC
- by Lars Pontoppidan et al., see sdcard.c|h and config.h.
- FAT filesystem access based on code from ChaN and Jim Brain, see ff.c|h.
- 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; version 2 of the License only.
- 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, write to the Free Software
- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- timer.c: System timer (and button debouncer)
- */
- #include "config.h"
- #include <avr/interrupt.h>
- #include <avr/io.h>
- #include "avrcompat.h"
- #include "led.h"
- #include "timer.h"
- volatile tick_t ticks;
- // Logical buttons
- volatile uint8_t active_keys;
- // Physical buttons
- uint8_t buttonstate;
- tick_t lastbuttonchange;
- /* Called by the timer interrupt when the button state has changed */
- static void buttons_changed(void) {
- /* Check if the previous state was stable for two ticks */
- if (time_after(ticks, lastbuttonchange+2)) {
- if (active_keys & IGNORE_KEYS) {
- active_keys &= ~IGNORE_KEYS;
- } else if (!(buttonstate & (BUTTON_PREV|BUTTON_NEXT))) {
- /* Both buttons held down */
- active_keys |= KEY_HOME;
- } else if (!(buttonstate & BUTTON_NEXT) &&
- (BUTTON_PIN & BUTTON_NEXT)) {
- /* "Next" button released */
- active_keys |= KEY_NEXT;
- } else if (!(buttonstate & BUTTON_PREV) &&
- (BUTTON_PIN & BUTTON_NEXT)) {
- active_keys |= KEY_PREV;
- }
- }
- lastbuttonchange = ticks;
- buttonstate = BUTTON_PIN & BUTTON_MASK;
- }
- /* The main timer interrupt */
- ISR(TIMER1_COMPA_vect) {
- uint8_t tmp = BUTTON_PIN & BUTTON_MASK;
- if (tmp != buttonstate) {
- buttons_changed();
- }
- ticks++;
- #ifdef SINGLE_LED
- if (led_state & LED_ERROR) {
- if ((ticks & 15) == 0)
- DIRTY_LED_PORT ^= DIRTY_LED_BIT();
- } else {
- if ((led_state & LED_BUSY) || (led_state & LED_DIRTY)) {
- DIRTY_LED_ON();
- } else {
- DIRTY_LED_OFF();
- }
- }
- #else
- if (led_state & LED_ERROR)
- if ((ticks & 15) == 0)
- DIRTY_LED_PORT ^= DIRTY_LED_BIT();
- #endif
- /* Sleep button triggers when held down for 2sec */
- if (time_after(ticks, lastbuttonchange+2)) {
- if (!(buttonstate & BUTTON_NEXT) &&
- (buttonstate & BUTTON_PREV) &&
- time_after(ticks, lastbuttonchange+2*HZ) &&
- !key_pressed(KEY_SLEEP)) {
- /* Set ignore flag so the release doesn't trigger KEY_NEXT */
- active_keys |= KEY_SLEEP | IGNORE_KEYS;
- /* Avoid triggering for the next two seconds */
- lastbuttonchange = ticks;
- }
- }
- #if CONFIG_RTC_VARIANT == 1
- increment_rtc();
- #endif
- #ifdef CONFIG_REMOTE_DISPLAY
- /* Check if the display wants to be queried */
- if (!(SOFTI2C_PIN & _BV(SOFTI2C_BIT_INTRQ))) {
- active_keys |= KEY_DISPLAY;
- }
- #endif
- }
- void timer_init(void) {
- /* Count F_CPU/8 in timer 0 */
- TCCR0B = _BV(CS01);
- /* Set up a 100Hz interrupt using timer 1 */
- OCR1A = 1249;
- TCNT1 = 0;
- TCCR1A = 0;
- TCCR1B = _BV(WGM12) | _BV(CS10) | _BV(CS11);
- TIMSK1 |= _BV(OCIE1A);
- /* Buttons */
- BUTTON_DDR &= (uint8_t)~BUTTON_MASK;
- BUTTON_PORT |= BUTTON_MASK;
- }
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