4 * Copyright 2004 Giovanni Bajo
5 * Copyright 2004 Develer S.r.l. (http://www.develer.com/)
6 * This file is part of DevLib - See README.devlib for information.
11 * \author Giovanni Bajo <rasky@develer.com>
13 * \brief Driver module for DSP56K
18 *#* Revision 1.8 2005/11/04 16:20:02 bernie
19 *#* Fix reference to README.devlib in header.
21 *#* Revision 1.7 2005/04/11 19:10:28 bernie
22 *#* Include top-level headers from cfg/ subdir.
24 *#* Revision 1.6 2004/11/16 22:37:14 bernie
25 *#* Replace IPTR with iptr_t.
27 *#* Revision 1.5 2004/08/25 14:12:08 rasky
28 *#* Aggiornato il comment block dei log RCS
30 *#* Revision 1.4 2004/07/30 14:27:49 rasky
31 *#* Aggiornati alcuni file DSP56k per la nuova libreria di IRQ management
33 *#* Revision 1.3 2004/06/06 18:30:34 bernie
34 *#* Import DSP56800 changes from SC.
36 *#* Revision 1.2 2004/06/03 11:27:09 bernie
37 *#* Add dual-license information.
39 *#* Revision 1.1 2004/05/23 18:23:30 bernie
40 *#* Import drv/timer module.
44 #ifndef DRV_TIMER_DSP56K_H
45 #define DRV_TIMER_DSP56K_H
48 #include <DSP56F807.h>
49 #include <cfg/compiler.h>
53 // Calculate register pointer and irq vector from hw.h setting
54 #define REG_SYSTEM_TIMER PP_CAT(REG_TIMER_, SYSTEM_TIMER)
55 #define SYSTEM_TIMER_IRQ_VECTOR PP_CAT(IRQ_TIMER_, SYSTEM_TIMER)
57 //! Prescaler for the system timer
58 #define TIMER_PRESCALER 16
60 //! Frequency of the hardware high precision timer
61 #define TIMER_HW_HPTICKS_PER_SEC (IPBUS_FREQ / TIMER_PRESCALER)
63 //! Type of time expressed in ticks of the hardware high precision timer
64 typedef uint16_t hptime_t;
66 static void system_timer_isr(UNUSED(iptr_t, arg));
68 static void timer_hw_init(void)
72 // Clear compare flag status and enable interrupt on compare
73 REG_SYSTEM_TIMER->SCR &= ~REG_TIMER_SCR_TCF;
74 REG_SYSTEM_TIMER->SCR |= REG_TIMER_SCR_TCFIE;
76 // Calculate the compare value needed to generate an interrupt exactly
77 // TICKS_PER_SEC times each second (usually, every millisecond). Check that
78 // the calculation is accurate, otherwise there is a precision error
79 // (probably the prescaler is too big or too small).
80 compare = TIMER_HW_HPTICKS_PER_SEC / TICKS_PER_SEC;
81 ASSERT((uint32_t)compare * TICKS_PER_SEC == IPBUS_FREQ / TIMER_PRESCALER);
82 REG_SYSTEM_TIMER->CMP1 = compare;
84 // The value for reload (at initializationa and after compare is met) is zero
85 REG_SYSTEM_TIMER->LOAD = 0;
87 // Set the interrupt handler and priority
88 irq_install(SYSTEM_TIMER_IRQ_VECTOR, &system_timer_isr, NULL);
89 irq_setpriority(SYSTEM_TIMER_IRQ_VECTOR, IRQ_PRIORITY_SYSTEM_TIMER);
91 // Small preprocessor trick to generate the REG_TIMER_CTRL_PRIMARY_IPBYNN macro
92 // needed to set the prescaler
93 #define REG_CONTROL_PRESCALER PP_CAT(REG_TIMER_CTRL_PRIMARY_IPBY, TIMER_PRESCALER)
95 // Setup the counter and start counting
96 REG_SYSTEM_TIMER->CTRL =
97 REG_TIMER_CTRL_MODE_RISING | // count rising edges (normal)
98 REG_CONTROL_PRESCALER | // frequency (IPbus / TIMER_PRESCALER)
99 REG_TIMER_CTRL_LENGTH; // up to CMP1, then reload
102 INLINE void timer_hw_irq(void)
104 // Clear the overflow flag so that we are ready for another interrupt
105 REG_SYSTEM_TIMER->SCR &= ~REG_TIMER_SCR_TCF;
108 INLINE hptime_t timer_hw_hpread(void)
110 return REG_SYSTEM_TIMER->CNTR;
113 #define DEFINE_TIMER_ISR \
114 static void system_timer_isr(UNUSED(iptr_t, arg))
116 #endif /* DRV_TIMER_DSP56_H */