Added port for ATmega8 - but not quite small enough yet. Compiled for ATmega168 (but at 8734 bytes of flash).

2008-09-27 22:19:23 +00:00
parent 437de29ce7
commit 67a7cdbc12
23 changed files with 4645 additions and 0 deletions
@@ -0,0 +1,109 @@
+/**************************************************************************
+*
+* Copyright (C) 2007 Steve Karg <skarg@users.sourceforge.net>
+*
+* Permission is hereby granted, free of charge, to any person obtaining
+* a copy of this software and associated documentation files (the
+* "Software"), to deal in the Software without restriction, including
+* without limitation the rights to use, copy, modify, merge, publish,
+* distribute, sublicense, and/or sell copies of the Software, and to
+* permit persons to whom the Software is furnished to do so, subject to
+* the following conditions:
+*
+* The above copyright notice and this permission notice shall be included
+* in all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*
+*********************************************************************/
+#include <stdbool.h>
+#include <stdint.h>
+#include "hardware.h"
+
+/* This module is a 1 millisecond timer */
+
+/* Prescaling: 1, 8, 64, 256, 1024 */
+#define TIMER_PRESCALER 64
+/* Count: Timer0 counts up to 0xFF and then signals overflow */
+#define TIMER_TICKS (F_CPU/TIMER_PRESCALER/1000)
+#if (TIMER_TICKS > 0xFF)
+#error Timer Prescaler value is too small
+#endif
+#define TIMER_COUNT (0xFF-TIMER_TICKS)
+/* millisecond timer count */
+static volatile uint16_t Timer_Silence;
+
+/* FIXME: Configure the Timer */
+void timer_init(
+    void)
+{
+    /* Normal Operation */
+    TCCR1A = 0;
+    /* CSn2 CSn1 CSn0 Description
+       ---- ---- ---- -----------
+       0    0    0  No Clock Source
+       0    0    1  No prescaling
+       0    1    0  CLKio/8
+       0    1    1  CLKio/64
+       1    0    0  CLKio/256
+       1    0    1  CLKio/1024
+       1    1    0  Falling Edge of T0 (external)
+       1    1    1  Rising Edge of T0 (external)
+     */
+#if defined(__AVR_ATmega168__)
+    TCCR0B = _BV(CS01) | _BV(CS00);
+    /* Clear any TOV1 Flag set when the timer overflowed */
+    BIT_CLEAR(TIFR0, TOV0);
+    /* Initial value */
+    TCNT0 = TIMER_COUNT;
+    /* Enable the overflow interrupt */
+    BIT_SET(TIMSK0, TOIE0);
+    /* Clear the Power Reduction Timer/Counter0 */
+    BIT_CLEAR(PRR, PRTIM0);
+#endif
+}
+
+/* Timer interupt */
+/* note: Global interupts must be enabled - sei() */
+/* Timer Overflowed!  Increment the time. */
+ISR(TIMER0_OVF_vect)
+{
+    /* Set the counter for the next interrupt */
+    TCNT0 = TIMER_COUNT;
+    /* Overflow Flag is automatically cleared */
+    /* Update the global timer */
+    Timer_Silence++;
+}
+
+/* return true if time has expired */
+bool timer_silence_elapsed(
+    uint16_t value)
+{
+    bool status = false;
+    uint8_t sreg;
+
+    sreg = SREG;
+    __disable_interrupt();
+    if (Timer_Silence >= value) {
+        status = true;
+    }
+    SREG = sreg;
+
+    return status;
+}
+
+void timer_silence_reset(void)
+{
+    uint8_t sreg;
+
+    sreg = SREG;
+    __disable_interrupt();
+    Timer_Silence = 0;
+    SREG = sreg;
+}