4 * Copyright 2004 Giovanni Bajo
5 * Copyright 2004 Develer S.r.l. (http://www.develer.com/)
6 * This file is part of DevLib - See devlib/README for information.
11 * \author Giovanni Bajo <rasky@develer.com>
13 * \brief Driver module for DSP56K
18 *#* Revision 1.7 2005/04/11 19:10:28 bernie
19 *#* Include top-level headers from cfg/ subdir.
21 *#* Revision 1.6 2004/11/16 22:37:14 bernie
22 *#* Replace IPTR with iptr_t.
24 *#* Revision 1.5 2004/08/25 14:12:08 rasky
25 *#* Aggiornato il comment block dei log RCS
27 *#* Revision 1.4 2004/07/30 14:27:49 rasky
28 *#* Aggiornati alcuni file DSP56k per la nuova libreria di IRQ management
30 *#* Revision 1.3 2004/06/06 18:30:34 bernie
31 *#* Import DSP56800 changes from SC.
33 *#* Revision 1.2 2004/06/03 11:27:09 bernie
34 *#* Add dual-license information.
36 *#* Revision 1.1 2004/05/23 18:23:30 bernie
37 *#* Import drv/timer module.
41 #ifndef DRV_TIMER_DSP56K_H
42 #define DRV_TIMER_DSP56K_H
45 #include <DSP56F807.h>
46 #include <cfg/compiler.h>
50 // Calculate register pointer and irq vector from hw.h setting
51 #define REG_SYSTEM_TIMER PP_CAT(REG_TIMER_, SYSTEM_TIMER)
52 #define SYSTEM_TIMER_IRQ_VECTOR PP_CAT(IRQ_TIMER_, SYSTEM_TIMER)
54 //! Prescaler for the system timer
55 #define TIMER_PRESCALER 16
57 //! Frequency of the hardware high precision timer
58 #define TIMER_HW_HPTICKS_PER_SEC (IPBUS_FREQ / TIMER_PRESCALER)
60 //! Type of time expressed in ticks of the hardware high precision timer
61 typedef uint16_t hptime_t;
63 static void system_timer_isr(UNUSED(iptr_t, arg));
65 static void timer_hw_init(void)
69 // Clear compare flag status and enable interrupt on compare
70 REG_SYSTEM_TIMER->SCR &= ~REG_TIMER_SCR_TCF;
71 REG_SYSTEM_TIMER->SCR |= REG_TIMER_SCR_TCFIE;
73 // Calculate the compare value needed to generate an interrupt exactly
74 // TICKS_PER_SEC times each second (usually, every millisecond). Check that
75 // the calculation is accurate, otherwise there is a precision error
76 // (probably the prescaler is too big or too small).
77 compare = TIMER_HW_HPTICKS_PER_SEC / TICKS_PER_SEC;
78 ASSERT((uint32_t)compare * TICKS_PER_SEC == IPBUS_FREQ / TIMER_PRESCALER);
79 REG_SYSTEM_TIMER->CMP1 = compare;
81 // The value for reload (at initializationa and after compare is met) is zero
82 REG_SYSTEM_TIMER->LOAD = 0;
84 // Set the interrupt handler and priority
85 irq_install(SYSTEM_TIMER_IRQ_VECTOR, &system_timer_isr, NULL);
86 irq_setpriority(SYSTEM_TIMER_IRQ_VECTOR, IRQ_PRIORITY_SYSTEM_TIMER);
88 // Small preprocessor trick to generate the REG_TIMER_CTRL_PRIMARY_IPBYNN macro
89 // needed to set the prescaler
90 #define REG_CONTROL_PRESCALER PP_CAT(REG_TIMER_CTRL_PRIMARY_IPBY, TIMER_PRESCALER)
92 // Setup the counter and start counting
93 REG_SYSTEM_TIMER->CTRL =
94 REG_TIMER_CTRL_MODE_RISING | // count rising edges (normal)
95 REG_CONTROL_PRESCALER | // frequency (IPbus / TIMER_PRESCALER)
96 REG_TIMER_CTRL_LENGTH; // up to CMP1, then reload
99 INLINE void timer_hw_irq(void)
101 // Clear the overflow flag so that we are ready for another interrupt
102 REG_SYSTEM_TIMER->SCR &= ~REG_TIMER_SCR_TCF;
105 INLINE hptime_t timer_hw_hpread(void)
107 return REG_SYSTEM_TIMER->CNTR;
110 #define DEFINE_TIMER_ISR \
111 static void system_timer_isr(UNUSED(iptr_t, arg))
113 #endif /* DRV_TIMER_DSP56_H */