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 1.5 2004/08/25 14:12:08 rasky
19 *#* Aggiornato il comment block dei log RCS
21 *#* Revision 1.4 2004/07/30 14:27:49 rasky
22 *#* Aggiornati alcuni file DSP56k per la nuova libreria di IRQ management
24 *#* Revision 1.3 2004/06/06 18:30:34 bernie
25 *#* Import DSP56800 changes from SC.
27 *#* Revision 1.2 2004/06/03 11:27:09 bernie
28 *#* Add dual-license information.
30 *#* Revision 1.1 2004/05/23 18:23:30 bernie
31 *#* Import drv/timer module.
35 #ifndef DRV_TIMER_DSP56K_H
36 #define DRV_TIMER_DSP56K_H
39 #include <DSP56F807.h>
44 // Calculate register pointer and irq vector from hw.h setting
45 #define REG_SYSTEM_TIMER PP_CAT(REG_TIMER_, SYSTEM_TIMER)
46 #define SYSTEM_TIMER_IRQ_VECTOR PP_CAT(IRQ_TIMER_, SYSTEM_TIMER)
48 //! Prescaler for the system timer
49 #define TIMER_PRESCALER 16
51 //! Frequency of the hardware high precision timer
52 #define TIMER_HW_HPTICKS_PER_SEC (IPBUS_FREQ / TIMER_PRESCALER)
54 //! Type of time expressed in ticks of the hardware high precision timer
55 typedef uint16_t hptime_t;
57 static void system_timer_isr(UNUSED(IPTR, arg));
59 static void timer_hw_init(void)
63 // Clear compare flag status and enable interrupt on compare
64 REG_SYSTEM_TIMER->SCR &= ~REG_TIMER_SCR_TCF;
65 REG_SYSTEM_TIMER->SCR |= REG_TIMER_SCR_TCFIE;
67 // Calculate the compare value needed to generate an interrupt exactly
68 // TICKS_PER_SEC times each second (usually, every millisecond). Check that
69 // the calculation is accurate, otherwise there is a precision error
70 // (probably the prescaler is too big or too small).
71 compare = TIMER_HW_HPTICKS_PER_SEC / TICKS_PER_SEC;
72 ASSERT((uint32_t)compare * TICKS_PER_SEC == IPBUS_FREQ / TIMER_PRESCALER);
73 REG_SYSTEM_TIMER->CMP1 = compare;
75 // The value for reload (at initializationa and after compare is met) is zero
76 REG_SYSTEM_TIMER->LOAD = 0;
78 // Set the interrupt handler and priority
79 irq_install(SYSTEM_TIMER_IRQ_VECTOR, &system_timer_isr, NULL);
80 irq_setpriority(SYSTEM_TIMER_IRQ_VECTOR, IRQ_PRIORITY_SYSTEM_TIMER);
82 // Small preprocessor trick to generate the REG_TIMER_CTRL_PRIMARY_IPBYNN macro
83 // needed to set the prescaler
84 #define REG_CONTROL_PRESCALER PP_CAT(REG_TIMER_CTRL_PRIMARY_IPBY, TIMER_PRESCALER)
86 // Setup the counter and start counting
87 REG_SYSTEM_TIMER->CTRL =
88 REG_TIMER_CTRL_MODE_RISING | // count rising edges (normal)
89 REG_CONTROL_PRESCALER | // frequency (IPbus / TIMER_PRESCALER)
90 REG_TIMER_CTRL_LENGTH; // up to CMP1, then reload
93 INLINE void timer_hw_irq(void)
95 // Clear the overflow flag so that we are ready for another interrupt
96 REG_SYSTEM_TIMER->SCR &= ~REG_TIMER_SCR_TCF;
99 INLINE hptime_t timer_hw_hpread(void)
101 return REG_SYSTEM_TIMER->CNTR;
104 #define DEFINE_TIMER_ISR \
105 static void system_timer_isr(UNUSED(IPTR, arg))
107 #endif /* DRV_TIMER_DSP56_H */