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