adjust root folder

2019-10-08 23:47:53 -05:00
parent b6fc50ddea
commit a42e8f507c
1258 changed files with 26 additions and 214 deletions
@@ -0,0 +1,165 @@
+/**************************************************************************
+*
+* Copyright (C) 2009 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"
+#include "timer.h"
+
+#ifndef F_CPU
+#error "F_CPU must be defined for Timer configuration."
+#endif
+/* Timer2 Prescaling: 1, 8, 32, 64, 128, 256, or 1024 */
+#define TIMER_MICROSECONDS 1000UL
+#define TIMER_TICKS(p) \
+  (((((F_CPU)/(p))/1000UL) \
+  *(TIMER_MICROSECONDS))/1000UL)
+#define TIMER_TICKS_MAX 255UL
+/* adjust the prescaler for the processor clock */
+#if (TIMER_TICKS(1) <= TIMER_TICKS_MAX)
+#define TIMER2_PRESCALER 1
+#elif (TIMER_TICKS(8) <= TIMER_TICKS_MAX)
+#define TIMER2_PRESCALER 8
+#elif (TIMER_TICKS(32) <= TIMER_TICKS_MAX)
+#define TIMER2_PRESCALER 32
+#elif (TIMER_TICKS(64) <= TIMER_TICKS_MAX)
+#define TIMER2_PRESCALER 64
+#elif (TIMER_TICKS(128) <= TIMER_TICKS_MAX)
+#define TIMER2_PRESCALER 128
+#elif (TIMER_TICKS(256) <= TIMER_TICKS_MAX)
+#define TIMER2_PRESCALER 256
+#elif (TIMER_TICKS(1024) <= TIMER_TICKS_MAX)
+#define TIMER2_PRESCALER 1024
+#else
+#error "TIMER2: F_CPU too large for timer prescaler."
+#endif
+#define TIMER2_TICKS TIMER_TICKS(TIMER2_PRESCALER)
+/* Timer counts up from count to TIMER_TICKS_MAX and then signals overflow */
+#define TIMER2_COUNT (TIMER_TICKS_MAX-TIMER2_TICKS)
+
+/* counter for the the timer which wraps every 49.7 days */
+static volatile uint32_t Millisecond_Counter;
+static volatile uint8_t Millisecond_Counter_Byte;
+
+/*************************************************************************
+* Description: Timer Interrupt Handler
+* Returns: nothing
+* Notes: none
+*************************************************************************/
+static inline void timer_interrupt_handler(
+    void)
+{
+    /* Set the counter for the next interrupt */
+    TCNT2 = TIMER2_COUNT;
+    Millisecond_Counter++;
+    Millisecond_Counter_Byte++;
+}
+
+/*************************************************************************
+* Description: Timer Interrupt Service Routine - Timer Overflowed!
+* Returns: none
+* Notes: Global interupts must be enabled
+*************************************************************************/
+ISR(TIMER2_OVF_vect)
+{
+    timer_interrupt_handler();
+}
+
+/*************************************************************************
+* Description: returns the current millisecond count
+* Returns: none
+* Notes: This method only disables the timer overflow interrupt.
+*************************************************************************/
+uint32_t timer_milliseconds(
+    void)
+{
+    uint32_t timer_value;       /* return value */
+
+    /* Disable the overflow interrupt.
+       Prevents value corruption that would happen if interrupted */
+    BIT_CLEAR(TIMSK2, TOIE2);
+    timer_value = Millisecond_Counter;
+    /* Enable the overflow interrupt */
+    BIT_SET(TIMSK2, TOIE2);
+
+    return timer_value;
+}
+
+/*************************************************************************
+* Description: returns the current millisecond count
+* Returns: none
+* Notes: This method only disables the timer overflow interrupt.
+*************************************************************************/
+uint8_t timer_milliseconds_byte(
+    void)
+{
+    return Millisecond_Counter;
+}
+
+/*************************************************************************
+* Description: Initialization for Timer
+* Returns: none
+* Notes: none
+*************************************************************************/
+void timer_init(
+    void)
+{
+    /* Normal Operation */
+    TCCR2A = 0;
+    /* Timer2: prescale selections:
+       CSn2 CSn1 CSn0 Description
+       ---- ---- ---- -----------
+       0    0    0  No Clock Source
+       0    0    1  No prescaling
+       0    1    0  CLKt2s/8
+       0    1    1  CLKt2s/32
+       1    0    0  CLKt2s/64
+       1    0    1  CLKt2s/128
+       1    1    0  CLKt2s/256
+       1    1    1  CLKt2s/1024
+     */
+#if (TIMER2_PRESCALER==1)
+    TCCR2B = _BV(CS20);
+#elif (TIMER2_PRESCALER==8)
+    TCCR2B = _BV(CS21);
+#elif (TIMER2_PRESCALER==32)
+    TCCR2B = _BV(CS21) | _BV(CS20);
+#elif (TIMER2_PRESCALER==64)
+    TCCR2B = _BV(CS22);
+#elif (TIMER2_PRESCALER==128)
+    TCCR2B = _BV(CS22) | _BV(CS20);
+#elif (TIMER2_PRESCALER==256)
+    TCCR2B = _BV(CS22) | _BV(CS21);
+#elif (TIMER2_PRESCALER==1024)
+    TCCR2B = _BV(CS22) | _BV(CS21) | _BV(CS20);
+#else
+#error Timer2 Prescale: Invalid Value
+#endif
+    /* Clear any TOV Flag set when the timer overflowed - by setting! */
+    BIT_SET(TIFR2, TOV2);
+    /* Initial value */
+    TCNT2 = TIMER2_COUNT;
+    /* Enable the overflow interrupt */
+    BIT_SET(TIMSK2, TOIE2);
+    power_timer2_enable();
+}