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29 * Copyright 2007 Develer S.r.l. (http://www.develer.com/)
35 * \author Francesco Sacchi <batt@develer.com>
37 * \brief Low-level timer module for Atmel AT91 (interface).
40 #ifndef DRV_AT91_TIMER_H
41 #define DRV_AT91_TIMER_H
43 #include <hw/hw_cpufreq.h> /* CPU_FREQ */
45 #include "cfg/cfg_timer.h" /* CONFIG_TIMER */
46 #include <cfg/compiler.h> /* uint8_t */
47 #include <cfg/macros.h> /* BV */
52 * \name Values for CONFIG_TIMER.
54 * Select which hardware timer interrupt to use for system clock and softtimers.
56 * $WIZ$ timer_select = "TIMER_ON_PIT", "TIMER_DEFAULT"
58 #define TIMER_ON_PIT 1 ///< System timer on Periodic interval timer
60 #define TIMER_DEFAULT TIMER_ON_PIT ///< Default system timer
63 * Hardware dependent timer initialization.
65 #if (CONFIG_TIMER == TIMER_ON_PIT)
68 * On ARM all system IRQs are handled by the sysirq_dispatcher, so the actual
69 * timer handler can be treated like any other normal routine.
71 #define DEFINE_TIMER_ISR void timer_handler(void); \
72 void timer_handler(void)
74 #define TIMER_TICKS_PER_SEC 1000
75 #define TIMER_HW_CNT (CPU_FREQ / (16 * TIMER_TICKS_PER_SEC) - 1)
77 /** Frequency of the hardware high-precision timer. */
78 #define TIMER_HW_HPTICKS_PER_SEC (CPU_FREQ / 16)
80 /** Type of time expressed in ticks of the hardware high-precision timer */
81 typedef uint32_t hptime_t;
82 #define SIZEOF_HPTIME_T 4
84 INLINE void timer_hw_irq(void)
86 /* Reset counters, this is needed to reset timer and interrupt flags */
87 uint32_t dummy = PIVR;
91 INLINE bool timer_hw_triggered(void)
93 return PIT_SR & BV(PITS);
96 INLINE hptime_t timer_hw_hpread(void)
98 /* In the upper part of PIT_PIIR there is unused data */
99 return PIIR & CPIV_MASK;
104 #error Unimplemented value for CONFIG_TIMER
105 #endif /* CONFIG_TIMER */
107 void timer_hw_init(void);
110 #endif /* DRV_TIMER_AT91_H */