archive MK1 AVR source

2010-09-06 23:51:48 +02:00
parent a6d66e7a8b
commit a9b84c3e0b
54 changed files with 1220 additions and 793 deletions
--- a/mk1-src/timer.h
+++ b/mk1-src/timer.h
@@ -0,0 +1,121 @@
+/* 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.h: System timer (and button-debouncer)
+
+*/
+
+#ifndef TIMER_H
+#define TIMER_H
+
+#include <util/atomic.h>
+
+// Bit masks for the (simulated) keys
+#define KEY_NEXT    (1<<0)
+#define KEY_PREV    (1<<1)
+#define KEY_HOME    (1<<2)
+#define KEY_SLEEP   (1<<3)
+/* Remote display service request */
+#define KEY_DISPLAY (1<<4)
+
+#define IGNORE_KEYS (1<<7)
+
+/// Logical keys that were pressed - must be reset by the reader.
+extern volatile uint8_t active_keys;
+
+#define key_pressed(x) (active_keys & (x))
+#define reset_key(x) active_keys &= (uint8_t)~(x)
+#define ignore_keys() active_keys = IGNORE_KEYS;
+
+typedef uint16_t tick_t;
+
+/// Global timing variable, 100 ticks per second
+/// Use atomic access or getticks() !
+extern volatile tick_t ticks;
+#define HZ 100
+
+/**
+ * getticks - return the current system tick count
+ *
+ * This inline function returns the current system tick count.
+ */
+static inline tick_t getticks(void) {
+  tick_t tmp;
+  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+    tmp = ticks;
+  }
+  return tmp;
+}
+
+#define MS_TO_TICKS(x) (x/10)
+
+/* Adapted from Linux 2.6 include/linux/jiffies.h:
+ *
+ *      These inlines deal with timer wrapping correctly. You are
+ *      strongly encouraged to use them
+ *      1. Because people otherwise forget
+ *      2. Because if the timer wrap changes in future you won't have to
+ *         alter your driver code.
+ *
+ * time_after(a,b) returns true if the time a is after time b.
+ *
+ * Do this with "<0" and ">=0" to only test the sign of the result. A
+ * good compiler would generate better code (and a really good compiler
+ * wouldn't care). Gcc is currently neither.
+ * (">=0" refers to the time_after_eq macro which wasn't copied)
+ */
+#define time_after(a,b)         \
+         ((int16_t)(b) - (int16_t)(a) < 0)
+#define time_before(a,b)        time_after(b,a)
+
+
+/// Calculate timer start value for given timeout in microseconds
+#define TIMEOUT_US(x) (256-((float)F_CPU/10000000.0)*x)
+
+/**
+ * start_timeout - start a timeout using timer0
+ * @startval: starting value for timer
+ *
+ * This function sets timer 0 to the specified value and clears its overflow
+ * flag. Use in conjunction with TIMEOUT_US to cause a timer overflow after
+ * a specified number of microseconds. DON'T use a variable as a parameter to
+ * the TIMEOUT_US macro because that would require run-time float calculations.
+ */
+#define start_timeout(startval) do { TCNT0 = startval; TIFR0 |= _BV(TOV0); } while (0)
+
+/**
+ * has_timed_out - returns true if timeout was reached
+ *
+ * This function returns true if the overflow flag of timer 0 is set which
+ * (together with start_timeout and TIMEOUT_US) will happen when the
+ * specified time has elapsed.
+ */
+#define has_timed_out() (TIFR0 & _BV(TOV0))
+
+void timer_init(void);
+
+#endif