4 * This file is part of BeRTOS.
6 * Bertos is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 * As a special exception, you may use this file as part of a free software
21 * library without restriction. Specifically, if other files instantiate
22 * templates or use macros or inline functions from this file, or you compile
23 * this file and link it with other files to produce an executable, this
24 * file does not by itself cause the resulting executable to be covered by
25 * the GNU General Public License. This exception does not however
26 * invalidate any other reasons why the executable file might be covered by
27 * the GNU General Public License.
29 * Copyright 2003, 2004, 2005 Develer S.r.l. (http://www.develer.com/)
30 * Copyright 2000 Bernardo Innocenti <bernie@develer.com>
31 * This file is part of DevLib - See README.devlib for information.
36 * \author Bernardo Innocenti <bernie@develer.com>
37 * \author Francesco Sacchi <batt@develer.com>
39 * \brief Low-level timer module for AVR (interface).
44 *#* Revision 1.32 2007/10/08 12:14:32 batt
45 *#* Fix some review issues.
47 *#* Revision 1.31 2007/10/07 12:30:55 batt
48 *#* Add default timer for AVR.
50 *#* Revision 1.30 2007/06/07 14:35:12 batt
51 *#* Merge from project_ks.
53 *#* Revision 1.29 2007/03/21 11:01:36 batt
54 *#* Add missing support for ATMega1281.
56 *#* Revision 1.28 2006/07/19 12:56:26 bernie
57 *#* Convert to new Doxygen style.
59 *#* Revision 1.27 2006/05/18 00:38:24 bernie
60 *#* Use hw_cpu.h instead of ubiquitous hw.h.
62 *#* Revision 1.26 2006/02/21 21:28:02 bernie
63 *#* New time handling based on TIMER_TICKS_PER_SEC to support slow timers with ticks longer than 1ms.
65 *#* Revision 1.25 2005/07/19 07:26:37 bernie
66 *#* Refactor to decouple timer ticks from milliseconds.
68 *#* Revision 1.24 2005/04/11 19:10:28 bernie
69 *#* Include top-level headers from cfg/ subdir.
71 *#* Revision 1.23 2005/03/01 23:24:51 bernie
72 *#* Tweaks for avr-libc 1.2.x.
74 *#* Revision 1.21 2004/12/13 12:07:06 bernie
75 *#* DISABLE_IRQSAVE/ENABLE_IRQRESTORE: Convert to IRQ_SAVE_DISABLE/IRQ_RESTORE.
77 *#* Revision 1.20 2004/11/16 20:59:46 bernie
78 *#* Include <avr/io.h> explicitly.
80 *#* Revision 1.19 2004/10/19 08:56:41 bernie
81 *#* TIMER_STROBE_ON, TIMER_STROBE_OFF, TIMER_STROBE_INIT: Move from timer_avr.h to timer.h, where they really belong.
83 *#* Revision 1.18 2004/09/20 03:31:03 bernie
84 *#* Fix racy racy code.
86 #ifndef DRV_TIMER_AVR_H
87 #define DRV_TIMER_AVR_H
89 #include <appconfig.h> /* CONFIG_TIMER */
90 #include <cfg/compiler.h> /* uint8_t */
91 #include <hw_cpu.h> /* CLOCK_FREQ */
94 * \name Values for CONFIG_TIMER.
96 * Select which hardware timer interrupt to use for system clock and softtimers.
97 * \note The timer 1 overflow mode set the timer as a 24 kHz PWM.
101 #define TIMER_ON_OUTPUT_COMPARE0 1
102 #define TIMER_ON_OVERFLOW1 2
103 #define TIMER_ON_OUTPUT_COMPARE2 3
104 #define TIMER_ON_OVERFLOW3 4
106 #define TIMER_DEFAULT TIMER_ON_OUTPUT_COMPARE0 ///< Default system timer
110 * Hardware dependent timer initialization.
112 #if (CONFIG_TIMER == TIMER_ON_OUTPUT_COMPARE0)
114 #define TIMER_PRESCALER 64
115 #define TIMER_HW_BITS 8
116 #define DEFINE_TIMER_ISR SIGNAL(SIG_OUTPUT_COMPARE0)
117 #define TIMER_TICKS_PER_SEC 1000
118 #define TIMER_HW_CNT OCR_DIVISOR
120 /// Type of time expressed in ticks of the hardware high-precision timer
121 typedef uint8_t hptime_t;
123 #elif (CONFIG_TIMER == TIMER_ON_OVERFLOW1)
125 #define TIMER_PRESCALER 1
126 #define TIMER_HW_BITS 8
127 /** This value is the maximum in overflow based timers. */
128 #define TIMER_HW_CNT (1 << TIMER_HW_BITS)
129 #define DEFINE_TIMER_ISR SIGNAL(SIG_OVERFLOW1)
130 #define TIMER_TICKS_PER_SEC ((TIMER_HW_HPTICKS_PER_SEC + TIMER_HW_CNT / 2) / TIMER_HW_CNT)
132 /// Type of time expressed in ticks of the hardware high precision timer
133 typedef uint16_t hptime_t;
135 #elif (CONFIG_TIMER == TIMER_ON_OUTPUT_COMPARE2)
137 #define TIMER_PRESCALER 64
138 #define TIMER_HW_BITS 8
139 #if CPU_AVR_ATMEGA1281 || CPU_AVR_ATMEGA168
140 #define DEFINE_TIMER_ISR SIGNAL(SIG_OUTPUT_COMPARE2A)
142 #define DEFINE_TIMER_ISR SIGNAL(SIG_OUTPUT_COMPARE2)
144 #define TIMER_TICKS_PER_SEC 1000
145 /** Value for OCR register in output-compare based timers. */
146 #define TIMER_HW_CNT OCR_DIVISOR
149 /// Type of time expressed in ticks of the hardware high precision timer
150 typedef uint8_t hptime_t;
152 #elif (CONFIG_TIMER == TIMER_ON_OVERFLOW3)
154 #define TIMER_PRESCALER 1
155 #define TIMER_HW_BITS 8
156 /** This value is the maximum in overflow based timers. */
157 #define TIMER_HW_CNT (1 << TIMER_HW_BITS)
158 #define DEFINE_TIMER_ISR SIGNAL(SIG_OVERFLOW3)
159 #define TIMER_TICKS_PER_SEC ((TIMER_HW_HPTICKS_PER_SEC + TIMER_HW_CNT / 2) / TIMER_HW_CNT)
161 /// Type of time expressed in ticks of the hardware high precision timer
162 typedef uint16_t hptime_t;
165 #error Unimplemented value for CONFIG_TIMER
166 #endif /* CONFIG_TIMER */
169 /** Frequency of the hardware high precision timer. */
170 #define TIMER_HW_HPTICKS_PER_SEC ((CLOCK_FREQ + TIMER_PRESCALER / 2) / TIMER_PRESCALER)
173 * System timer: additional division after the prescaler
174 * 12288000 / 64 / 192 (0..191) = 1 ms
176 #define OCR_DIVISOR (((CLOCK_FREQ + TIMER_PRESCALER / 2) / TIMER_PRESCALER + TIMER_TICKS_PER_SEC / 2) / TIMER_TICKS_PER_SEC - 1)
178 /** Not needed, IRQ timer flag cleared automatically */
179 #define timer_hw_irq() do {} while (0)
181 /** Not needed, timer IRQ handler called only for timer source */
182 #define timer_hw_triggered() (true)
185 #endif /* DRV_TIMER_AVR_H */