drv/timer_avr.h

   1 /*!
   2  * \file
   3  * <!--
   4  * Copyright 2003,2004 Develer S.r.l. (http://www.develer.com/)
   5  * Copyright 2000 Bernardo Innocenti <bernie@develer.com>
   6  * This file is part of DevLib - See devlib/README for information.
   7  * -->
   8  *
   9  * \version $Id$
  10  *
  11  * \author Bernardo Innocenti <bernie@develer.com>
  12  *
  13  * \brief Low-level timer module for AVR
  14  */
  15
  16 /*
  17  * $Log$
  18  * Revision 1.6  2004/07/20 23:48:16  bernie
  19  * Finally remove redundant protos.
  20  *
  21  * Revision 1.5  2004/07/18 22:16:35  bernie
  22  * Add missing header; Prevent warning for project_ks-specific code.
  23  *
  24  * Revision 1.4  2004/06/27 15:22:15  aleph
  25  * Fix spacing
  26  *
  27  * Revision 1.3  2004/06/07 15:57:40  aleph
  28  * Update to latest AVR timer code
  29  *
  30  * Revision 1.2  2004/06/03 11:27:09  bernie
  31  * Add dual-license information.
  32  *
  33  * Revision 1.1  2004/05/23 18:23:30  bernie
  34  * Import drv/timer module.
  35  *
  36  */
  37
  38 #ifndef DRV_TIMER_AVR_H
  39 #define DRV_TIMER_AVR_H
  40
  41 #include <avr/wdt.h>
  42 #include <avr/signal.h>
  43
  44 #if defined(ARCH_BOARD_KC) && (ARCH & ARCH_BOARD_KC)
  45         #include <drv/adc.h>
  46 #endif
  47
  48
  49 #define timer_hw_irq()  /* Not needed, IRQ timer flag cleared automatically */
  50
  51 /*!
  52  * System timer: additional division after the prescaler
  53  * 12288000 / 64 / 192 (0..191) = 1 ms
  54  */
  55 #define OCR_DIVISOR 191
  56
  57 /*! HW dependent timer initialization  */
  58 #if defined(CONFIG_TIMER_ON_TIMER0)
  59
  60         //! Type of time expressed in ticks of the hardware high-precision timer
  61         typedef uint8_t hptime_t;
  62
  63         static void timer_hw_init(void)
  64         {
  65                 cpuflags_t flags;
  66                 DISABLE_IRQSAVE(flags);
  67
  68                 /* Reset Timer flags */
  69                 TIFR = BV(OCF0) | BV(TOV0);
  70
  71                 /* Setup Timer/Counter interrupt */
  72                 ASSR = 0x00;                  /* internal system clock */
  73                 TCCR0 = BV(WGM01) | BV(CS02); /* Clear on Compare match & prescaler = 64. When changing
  74                                                  prescaler change TIMER_HW_HPTICKS_PER_SEC too */
  75                 TCNT0 = 0x00;                 /* initialization of Timer/Counter */
  76                 OCR0 = OCR_DIVISOR;           /* Timer/Counter Output Compare Register */
  77
  78                 /* Enable timer interrupts: Timer/Counter2 Output Compare (OCIE2) */
  79                 TIMSK &= ~BV(TOIE0);
  80                 TIMSK |= BV(OCIE0);
  81
  82                 ENABLE_IRQRESTORE(flags);
  83         }
  84
  85         //! Frequency of the hardware high precision timer
  86         #define TIMER_HW_HPTICKS_PER_SEC  (CLOCK_FREQ / 64)
  87
  88         INLINE hptime_t timer_hw_hpread(void)
  89         {
  90                 return TCNT0;
  91         }
  92
  93 #elif defined(CONFIG_TIMER_ON_TIMER1_OVERFLOW)
  94
  95         //! Type of time expressed in ticks of the hardware high precision timer
  96         typedef uint16_t hptime_t;
  97
  98         static void timer_hw_init(void)
  99         {
 100                 cpuflags_t flags;
 101                 DISABLE_IRQSAVE(flags);
 102
 103                 /* Reset Timer overflow flag */
 104                 TIFR |= BV(TOV1);
 105
 106                 /* Fast PWM mode, 9 bit, 24 kHz, no prescaling. When changing freq or
 107                    resolution (top of TCNT), change TIMER_HW_HPTICKS_PER_SEC too */
 108                 TCCR1A |= BV(WGM11);
 109                 TCCR1A &= ~BV(WGM10);
 110                 TCCR1B |= BV(WGM12) | BV(CS10);
 111                 TCCR1B &= ~(BV(WGM13) | BV(CS11) | BV(CS12));
 112
 113                 TCNT1 = 0x00;         /* initialization of Timer/Counter */
 114
 115                 /* Enable timer interrupt: Timer/Counter1 Overflow */
 116                 TIMSK |= BV(TOIE1);
 117
 118                 ENABLE_IRQRESTORE(flags);
 119         }
 120
 121         //! Frequency of the hardware high precision timer
 122         #define TIMER_HW_HPTICKS_PER_SEC  (24000ul * 512)
 123
 124         INLINE hptime_t timer_hw_hpread(void)
 125         {
 126                 return TCNT1;
 127         }
 128
 129 #elif defined(CONFIG_TIMER_ON_TIMER2)
 130
 131         //! Type of time expressed in ticks of the hardware high precision timer
 132         typedef uint8_t hptime_t;
 133
 134         static void timer_hw_init(void)
 135         {
 136                 cpuflags_t flags;
 137                 DISABLE_IRQSAVE(flags);
 138
 139                 /* Reset Timer flags */
 140                 TIFR = BV(OCF2) | BV(TOV2);
 141
 142                 /* Setup Timer/Counter interrupt */
 143                 TCCR2 = BV(WGM21) | BV(CS21) | BV(CS20);
 144                 /* Clear on Compare match & prescaler = 64, internal sys clock.
 145                    When changing prescaler change TIMER_HW_HPTICKS_PER_SEC too */
 146                 TCNT2 = 0x00;         /* initialization of Timer/Counter */
 147                 OCR2 = OCR_DIVISOR;   /* Timer/Counter Output Compare Register */
 148
 149                 /* Enable timer interrupts: Timer/Counter2 Output Compare (OCIE2) */
 150                 TIMSK &= ~BV(TOIE2);
 151                 TIMSK |= BV(OCIE2);
 152
 153                 ENABLE_IRQRESTORE(flags);
 154         }
 155
 156         //! Frequency of the hardware high precision timer
 157         #define TIMER_HW_HPTICKS_PER_SEC  (CLOCK_FREQ / 64)
 158
 159         INLINE hptime_t timer_hw_hpread(void)
 160         {
 161                 return TCNT2;
 162         }
 163
 164 #else
 165         #error Choose witch timer to use with CONFIG_TIMER_ON_TIMERx
 166 #endif /* CONFIG_TIMER_ON_TIMERx */
 167
 168
 169 #if defined(CONFIG_TIMER_ON_TIMER1_OVERFLOW)
 170
 171         #define DEFINE_TIMER_ISR        \
 172                 static void timer_handler(void)
 173
 174         DEFINE_TIMER_ISR;
 175
 176         /*
 177          * Timer 1 overflow irq handler. It's called at the frequency of the timer 1
 178          * PWM (should be 24 kHz). It's too much for timer purposes, so the interrupt
 179          * handler is really a counter that call the true handler in timer.c
 180          * every 1 ms.
 181          */
 182         SIGNAL(SIG_OVERFLOW1)
 183         {
 184                 /*!
 185                  * How many overflow we have to count before calling the true timer handler.
 186                  * If timer overflow is at 24 kHz, with a value of 24 we have 1 ms between
 187                  * each call.
 188                  */
 189                 #define TIMER1_OVF_COUNT 24
 190
 191                 static uint8_t count = TIMER1_OVF_COUNT;
 192
 193                 count--;
 194                 if (!count)
 195                 {
 196                         timer_handler();
 197                         count = TIMER1_OVF_COUNT;
 198                 }
 199
 200         #if (ARCH & ARCH_BOARD_KC)
 201                 /*
 202                  * Super-optimization-hack: switch CPU ADC mux here, ASAP after the start
 203                  * of conversion (auto-triggered with timer 1 overflow).
 204                  * The switch can be done 2 ADC cycles after start of conversion.
 205                  * The handler prologue takes a little more than 32 CPU cycles: with
 206                  * the prescaler at 1/16 the timing should be correct even at the start
 207                  * of the handler.
 208                  *
 209                  * The switch is synchronized with the ADC handler using _adc_trigger_lock.
 210                  */
 211                 extern uint8_t _adc_idx_next;
 212                 extern bool _adc_trigger_lock;
 213
 214                 if (!_adc_trigger_lock)
 215                 {
 216                         TIMER_STROBE_ON;
 217                         ADC_SETCHN(_adc_idx_next);
 218                         TIMER_STROBE_OFF;
 219                         _adc_trigger_lock = true;
 220                 }
 221         #endif
 222         }
 223
 224 #elif defined (CONFIG_TIMER_ON_TIMER0)
 225
 226         #define DEFINE_TIMER_ISR        \
 227                 SIGNAL(SIG_OUTPUT_COMPARE0)
 228
 229 #elif defined(CONFIG_TIMER_ON_TIMER2)
 230
 231         #define DEFINE_TIMER_ISR        \
 232                 SIGNAL(SIG_OUTPUT_COMPARE2)
 233
 234 #else
 235         #error Choose witch timer to use with CONFIG_TIMER_ON_TIMERx
 236 #endif /* CONFIG_TIMER_ON_TIMERx */
 237
 238 #endif /* DRV_TIMER_AVR_H */