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