drv/timer_avr.c

   1 /*!
   2  * \file
   3  * <!--
   4  * Copyright 2005 Develer S.r.l. (http://www.develer.com/)
   5  * This file is part of DevLib - See README.devlib for information.
   6  * -->
   7  *
   8  * \version $Id$
   9  *
  10  * \author Bernardo Innocenti <bernie@develer.com>
  11  * \author Francesco Sacchi <batt@develer.com>
  12  *
  13  * \brief Low-level timer module for AVR (implementation).
  14  */
  15
  16 /*#*
  17  *#* $Log$
  18  *#* Revision 1.2  2006/05/18 00:37:58  bernie
  19  *#* Don't include unneeded header hw.h.
  20  *#*
  21  *#* Revision 1.1  2005/07/19 07:28:36  bernie
  22  *#* Refactor to decouple timer ticks from milliseconds.
  23  *#*
  24  *#* Revision 1.1  2005/05/24 09:17:58  batt
  25  *#* Move drivers to top-level.
  26  *#*
  27  *#*/
  28 #include <drv/timer_avr.h>
  29 #include <cfg/macros.h> // BV()
  30
  31 #include <avr/signal.h>
  32 #include <avr/io.h>
  33
  34 /*! HW dependent timer initialization  */
  35 #if (CONFIG_TIMER == TIMER_ON_OUTPUT_COMPARE0)
  36
  37         static void timer_hw_init(void)
  38         {
  39                 cpuflags_t flags;
  40                 IRQ_SAVE_DISABLE(flags);
  41
  42                 /* Reset Timer flags */
  43                 TIFR = BV(OCF0) | BV(TOV0);
  44
  45                 /* Setup Timer/Counter interrupt */
  46                 ASSR = 0x00;                  /* Internal system clock */
  47                 TCCR0 = BV(WGM01)             /* Clear on Compare match */
  48                         #if TIMER_PRESCALER == 64
  49                                 | BV(CS02)
  50                         #else
  51                                 #error Unsupported value of TIMER_PRESCALER
  52                         #endif
  53                 ;
  54                 TCNT0 = 0x00;                 /* Initialization of Timer/Counter */
  55                 OCR0 = OCR_DIVISOR;           /* Timer/Counter Output Compare Register */
  56
  57                 /* Enable timer interrupts: Timer/Counter2 Output Compare (OCIE2) */
  58                 TIMSK &= ~BV(TOIE0);
  59                 TIMSK |= BV(OCIE0);
  60
  61                 IRQ_RESTORE(flags);
  62         }
  63
  64         INLINE hptime_t timer_hw_hpread(void)
  65         {
  66                 return TCNT0;
  67         }
  68
  69 #elif (CONFIG_TIMER == TIMER_ON_OVERFLOW1)
  70
  71         static void timer_hw_init(void)
  72         {
  73                 cpuflags_t flags;
  74                 IRQ_SAVE_DISABLE(flags);
  75
  76                 /* Reset Timer overflow flag */
  77                 TIFR |= BV(TOV1);
  78
  79                 /* Fast PWM mode, 9 bit, 24 kHz, no prescaling. */
  80                 #if (TIMER_PRESCALER == 1) && (TIMER_HW_BITS == 9)
  81                         TCCR1A |= BV(WGM11);
  82                         TCCR1A &= ~BV(WGM10);
  83                         TCCR1B |= BV(WGM12) | BV(CS10);
  84                         TCCR1B &= ~(BV(WGM13) | BV(CS11) | BV(CS12));
  85                 /* Fast PWM mode, 8 bit, 24 kHz, no prescaling. */
  86                 #elif (TIMER_PRESCALER == 1) && (TIMER_HW_BITS == 8)
  87                         TCCR1A |= BV(WGM10);
  88                         TCCR1A &= ~BV(WGM11);
  89                         TCCR1B |= BV(WGM12) | BV(CS10);
  90                         TCCR1B &= ~(BV(WGM13) | BV(CS11) | BV(CS12));
  91                 #else
  92                         #error Unsupported value of TIMER_PRESCALER or TIMER_HW_BITS
  93                 #endif
  94
  95                 TCNT1 = 0x00;         /* initialization of Timer/Counter */
  96
  97                 /* Enable timer interrupt: Timer/Counter1 Overflow */
  98                 TIMSK |= BV(TOIE1);
  99
 100                 IRQ_RESTORE(flags);
 101         }
 102
 103         INLINE hptime_t timer_hw_hpread(void)
 104         {
 105                 return TCNT1;
 106         }
 107
 108 #elif (CONFIG_TIMER == TIMER_ON_OUTPUT_COMPARE2)
 109
 110         static void timer_hw_init(void)
 111         {
 112                 cpuflags_t flags;
 113                 IRQ_SAVE_DISABLE(flags);
 114
 115                 /* Reset Timer flags */
 116                 TIFR = BV(OCF2) | BV(TOV2);
 117
 118                 /* Setup Timer/Counter interrupt */
 119                 TCCR2 = BV(WGM21)
 120                         #if TIMER_PRESCALER == 64
 121                                 | BV(CS21) | BV(CS20)
 122                         #else
 123                                 #error Unsupported value of TIMER_PRESCALER
 124                         #endif
 125                 ;
 126                 /* Clear on Compare match & prescaler = 64, internal sys clock.
 127                    When changing prescaler change TIMER_HW_HPTICKS_PER_SEC too */
 128                 TCNT2 = 0x00;         /* initialization of Timer/Counter */
 129                 OCR2 = OCR_DIVISOR;   /* Timer/Counter Output Compare Register */
 130
 131                 /* Enable timer interrupts: Timer/Counter2 Output Compare (OCIE2) */
 132                 TIMSK &= ~BV(TOIE2);
 133                 TIMSK |= BV(OCIE2);
 134
 135                 IRQ_RESTORE(flags);
 136         }
 137
 138         INLINE hptime_t timer_hw_hpread(void)
 139         {
 140                 return TCNT2;
 141         }
 142 #elif (CONFIG_TIMER == TIMER_ON_OVERFLOW3)
 143
 144         static void timer_hw_init(void)
 145         {
 146                 cpuflags_t flags;
 147                 IRQ_SAVE_DISABLE(flags);
 148
 149                 /* Reset Timer overflow flag */
 150                 TIFR |= BV(TOV3);
 151
 152                 /* Fast PWM mode, 9 bit, 24 kHz, no prescaling. */
 153                 #if (TIMER_PRESCALER == 1) && (TIMER_HW_BITS == 9)
 154                         TCCR3A |= BV(WGM31);
 155                         TCCR3A &= ~BV(WGM30);
 156                         TCCR3B |= BV(WGM32) | BV(CS30);
 157                         TCCR3B &= ~(BV(WGM33) | BV(CS31) | BV(CS32));
 158                 /* Fast PWM mode, 8 bit, 24 kHz, no prescaling. */
 159                 #elif (TIMER_PRESCALER == 1) && (TIMER_HW_BITS == 8)
 160                         TCCR3A |= BV(WGM30);
 161                         TCCR3A &= ~BV(WGM31);
 162                         TCCR3B |= BV(WGM32) | BV(CS30);
 163                         TCCR3B &= ~(BV(WGM33) | BV(CS31) | BV(CS32));
 164                 #else
 165                         #error Unsupported value of TIMER_PRESCALER or TIMER_HW_BITS
 166                 #endif
 167
 168                 TCNT3 = 0x00;         /* initialization of Timer/Counter */
 169
 170                 /* Enable timer interrupt: Timer/Counter3 Overflow */
 171                 /* ATTENTION! TOIE3 is only on ETIMSK, not TIMSK */
 172                 ETIMSK |= BV(TOIE3);
 173
 174                 IRQ_RESTORE(flags);
 175         }
 176
 177         INLINE hptime_t timer_hw_hpread(void)
 178         {
 179                 return TCNT3;
 180         }
 181
 182 #else
 183         #error Unimplemented value for CONFIG_TIMER
 184 #endif /* CONFIG_TIMER */
 185