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