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 Bernie Innocenti <bernie@codewiz.org>
34 * \brief Low-level timer module for AVR (interface).
38 * \author Bernie Innocenti <bernie@codewiz.org>
39 * \author Francesco Sacchi <batt@develer.com>
43 #ifndef DRV_TIMER_AVR_H
44 #define DRV_TIMER_AVR_H
46 #include <hw/hw_cpufreq.h> /* CPU_FREQ */
48 #include "cfg/cfg_timer.h" /* CONFIG_TIMER */
49 #include <cfg/compiler.h> /* uint8_t */
50 #include <cfg/macros.h> /* DIV_ROUND */
53 #include <avr/interrupt.h>
56 * \name Values for CONFIG_TIMER.
58 * Select which hardware timer interrupt to use for system clock and softtimers.
59 * \note The timer 1 overflow mode set the timer as a 24 kHz PWM.
60 * $WIZ$ timer_select = "TIMER_ON_OUTPUT_COMPARE0", "TIMER_ON_OVERFLOW1", "TIMER_ON_OUTPUT_COMPARE2", "TIMER_ON_OVERFLOW3", "TIMER_DEFAULT"
62 #define TIMER_ON_OUTPUT_COMPARE0 1
63 #define TIMER_ON_OVERFLOW1 2
64 #define TIMER_ON_OUTPUT_COMPARE2 3
65 #define TIMER_ON_OVERFLOW3 4
67 #define TIMER_DEFAULT TIMER_ON_OUTPUT_COMPARE0 ///< Default system timer
70 * Hardware dependent timer initialization.
72 #if (CONFIG_TIMER == TIMER_ON_OUTPUT_COMPARE0)
74 #define TIMER_PRESCALER 64
75 #define TIMER_HW_BITS 8
76 #if CPU_AVR_ATMEGA1281 || CPU_AVR_ATMEGA168
77 #define DEFINE_TIMER_ISR SIGNAL(SIG_OUTPUT_COMPARE0A)
79 #define DEFINE_TIMER_ISR SIGNAL(SIG_OUTPUT_COMPARE0)
81 #define TIMER_TICKS_PER_SEC 1000
82 #define TIMER_HW_CNT OCR_DIVISOR
84 /// Type of time expressed in ticks of the hardware high-precision timer
85 typedef uint8_t hptime_t;
87 INLINE hptime_t timer_hw_hpread(void)
92 #elif (CONFIG_TIMER == TIMER_ON_OVERFLOW1)
94 #define TIMER_PRESCALER 1
95 #define TIMER_HW_BITS 8
96 /** This value is the maximum in overflow based timers. */
97 #define TIMER_HW_CNT (1 << TIMER_HW_BITS)
98 #define DEFINE_TIMER_ISR SIGNAL(SIG_OVERFLOW1)
99 #define TIMER_TICKS_PER_SEC DIV_ROUND(TIMER_HW_HPTICKS_PER_SEC, TIMER_HW_CNT)
101 /// Type of time expressed in ticks of the hardware high precision timer
102 typedef uint16_t hptime_t;
104 INLINE hptime_t timer_hw_hpread(void)
109 #elif (CONFIG_TIMER == TIMER_ON_OUTPUT_COMPARE2)
111 #define TIMER_PRESCALER 64
112 #define TIMER_HW_BITS 8
113 #if CPU_AVR_ATMEGA1281 || CPU_AVR_ATMEGA168
114 #define DEFINE_TIMER_ISR SIGNAL(SIG_OUTPUT_COMPARE2A)
116 #define DEFINE_TIMER_ISR SIGNAL(SIG_OUTPUT_COMPARE2)
118 #define TIMER_TICKS_PER_SEC 1000
119 /** Value for OCR register in output-compare based timers. */
120 #define TIMER_HW_CNT OCR_DIVISOR
122 /// Type of time expressed in ticks of the hardware high precision timer
123 typedef uint8_t hptime_t;
125 INLINE hptime_t timer_hw_hpread(void)
130 #elif (CONFIG_TIMER == TIMER_ON_OVERFLOW3)
132 #define TIMER_PRESCALER 1
133 #define TIMER_HW_BITS 8
134 /** This value is the maximum in overflow based timers. */
135 #define TIMER_HW_CNT (1 << TIMER_HW_BITS)
136 #define DEFINE_TIMER_ISR SIGNAL(SIG_OVERFLOW3)
137 #define TIMER_TICKS_PER_SEC DIV_ROUND(TIMER_HW_HPTICKS_PER_SEC, TIMER_HW_CNT)
139 /// Type of time expressed in ticks of the hardware high precision timer
140 typedef uint16_t hptime_t;
142 INLINE hptime_t timer_hw_hpread(void)
149 #error Unimplemented value for CONFIG_TIMER
150 #endif /* CONFIG_TIMER */
153 /** Frequency of the hardware high precision timer. */
154 #define TIMER_HW_HPTICKS_PER_SEC DIV_ROUND(CPU_FREQ, TIMER_PRESCALER)
157 * System timer: additional division after the prescaler
158 * 12288000 / 64 / 192 (0..191) = 1 ms
160 #define OCR_DIVISOR (DIV_ROUND(DIV_ROUND(CPU_FREQ, TIMER_PRESCALER), TIMER_TICKS_PER_SEC) - 1)
162 /** Not needed, IRQ timer flag cleared automatically */
163 #define timer_hw_irq() do {} while (0)
165 /** Not needed, timer IRQ handler called only for timer source */
166 #define timer_hw_triggered() (true)
168 void timer_hw_init(void);
170 #endif /* DRV_TIMER_AVR_H */