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 1.3  2006/06/12 21:37:02  marco
  19  *#* implemented some commands (ver and sleep)
  20  *#*
  21  *#* Revision 1.2  2006/05/18 00:37:58  bernie
  22  *#* Don't include unneeded header hw.h.
  23  *#*
  24  *#* Revision 1.1  2005/07/19 07:28:36  bernie
  25  *#* Refactor to decouple timer ticks from milliseconds.
  26  *#*
  27  *#* Revision 1.1  2005/05/24 09:17:58  batt
  28  *#* Move drivers to top-level.
  29  *#*
  30  *#*/
  31 #include <drv/timer_avr.h>
  32 #include <cfg/macros.h> // BV()
  33
  34 #include <avr/interrupt.h>
  35 #include <avr/io.h>
  36
  37 /*! HW dependent timer initialization  */
  38 #if (CONFIG_TIMER == TIMER_ON_OUTPUT_COMPARE0)
  39
  40         static void timer_hw_init(void)
  41         {
  42                 cpuflags_t flags;
  43                 IRQ_SAVE_DISABLE(flags);
  44
  45                 /* Reset Timer flags */
  46                 TIFR = BV(OCF0) | BV(TOV0);
  47
  48                 /* Setup Timer/Counter interrupt */
  49                 ASSR = 0x00;                  /* Internal system clock */
  50                 TCCR0 = BV(WGM01)             /* Clear on Compare match */
  51                         #if TIMER_PRESCALER == 64
  52                                 | BV(CS02)
  53                         #else
  54                                 #error Unsupported value of TIMER_PRESCALER
  55                         #endif
  56                 ;
  57                 TCNT0 = 0x00;                 /* Initialization of Timer/Counter */
  58                 OCR0 = OCR_DIVISOR;           /* Timer/Counter Output Compare Register */
  59
  60                 /* Enable timer interrupts: Timer/Counter2 Output Compare (OCIE2) */
  61                 TIMSK &= ~BV(TOIE0);
  62                 TIMSK |= BV(OCIE0);
  63
  64                 IRQ_RESTORE(flags);
  65         }
  66
  67         INLINE hptime_t timer_hw_hpread(void)
  68         {
  69                 return TCNT0;
  70         }
  71
  72 #elif (CONFIG_TIMER == TIMER_ON_OVERFLOW1)
  73
  74         static void timer_hw_init(void)
  75         {
  76                 cpuflags_t flags;
  77                 IRQ_SAVE_DISABLE(flags);
  78
  79                 /* Reset Timer overflow flag */
  80                 TIFR |= BV(TOV1);
  81
  82                 /* Fast PWM mode, 9 bit, 24 kHz, no prescaling. */
  83                 #if (TIMER_PRESCALER == 1) && (TIMER_HW_BITS == 9)
  84                         TCCR1A |= BV(WGM11);
  85                         TCCR1A &= ~BV(WGM10);
  86                         TCCR1B |= BV(WGM12) | BV(CS10);
  87                         TCCR1B &= ~(BV(WGM13) | BV(CS11) | BV(CS12));
  88                 /* Fast PWM mode, 8 bit, 24 kHz, no prescaling. */
  89                 #elif (TIMER_PRESCALER == 1) && (TIMER_HW_BITS == 8)
  90                         TCCR1A |= BV(WGM10);
  91                         TCCR1A &= ~BV(WGM11);
  92                         TCCR1B |= BV(WGM12) | BV(CS10);
  93                         TCCR1B &= ~(BV(WGM13) | BV(CS11) | BV(CS12));
  94                 #else
  95                         #error Unsupported value of TIMER_PRESCALER or TIMER_HW_BITS
  96                 #endif
  97
  98                 TCNT1 = 0x00;         /* initialization of Timer/Counter */
  99
 100                 /* Enable timer interrupt: Timer/Counter1 Overflow */
 101                 TIMSK |= BV(TOIE1);
 102
 103                 IRQ_RESTORE(flags);
 104         }
 105
 106         INLINE hptime_t timer_hw_hpread(void)
 107         {
 108                 return TCNT1;
 109         }
 110
 111 #elif (CONFIG_TIMER == TIMER_ON_OUTPUT_COMPARE2)
 112
 113         static void timer_hw_init(void)
 114         {
 115                 cpuflags_t flags;
 116                 IRQ_SAVE_DISABLE(flags);
 117
 118                 /* Reset Timer flags */
 119                 TIFR = BV(OCF2) | BV(TOV2);
 120
 121                 /* Setup Timer/Counter interrupt */
 122                 TCCR2 = BV(WGM21)
 123                         #if TIMER_PRESCALER == 64
 124                                 | BV(CS21) | BV(CS20)
 125                         #else
 126                                 #error Unsupported value of TIMER_PRESCALER
 127                         #endif
 128                 ;
 129                 /* Clear on Compare match & prescaler = 64, internal sys clock.
 130                    When changing prescaler change TIMER_HW_HPTICKS_PER_SEC too */
 131                 TCNT2 = 0x00;         /* initialization of Timer/Counter */
 132                 OCR2 = OCR_DIVISOR;   /* Timer/Counter Output Compare Register */
 133
 134                 /* Enable timer interrupts: Timer/Counter2 Output Compare (OCIE2) */
 135                 TIMSK &= ~BV(TOIE2);
 136                 TIMSK |= BV(OCIE2);
 137
 138                 IRQ_RESTORE(flags);
 139         }
 140
 141         INLINE hptime_t timer_hw_hpread(void)
 142         {
 143                 return TCNT2;
 144         }
 145 #elif (CONFIG_TIMER == TIMER_ON_OVERFLOW3)
 146
 147         static void timer_hw_init(void)
 148         {
 149                 cpuflags_t flags;
 150                 IRQ_SAVE_DISABLE(flags);
 151
 152                 /* Reset Timer overflow flag */
 153                 TIFR |= BV(TOV3);
 154
 155                 /* Fast PWM mode, 9 bit, 24 kHz, no prescaling. */
 156                 #if (TIMER_PRESCALER == 1) && (TIMER_HW_BITS == 9)
 157                         TCCR3A |= BV(WGM31);
 158                         TCCR3A &= ~BV(WGM30);
 159                         TCCR3B |= BV(WGM32) | BV(CS30);
 160                         TCCR3B &= ~(BV(WGM33) | BV(CS31) | BV(CS32));
 161                 /* Fast PWM mode, 8 bit, 24 kHz, no prescaling. */
 162                 #elif (TIMER_PRESCALER == 1) && (TIMER_HW_BITS == 8)
 163                         TCCR3A |= BV(WGM30);
 164                         TCCR3A &= ~BV(WGM31);
 165                         TCCR3B |= BV(WGM32) | BV(CS30);
 166                         TCCR3B &= ~(BV(WGM33) | BV(CS31) | BV(CS32));
 167                 #else
 168                         #error Unsupported value of TIMER_PRESCALER or TIMER_HW_BITS
 169                 #endif
 170
 171                 TCNT3 = 0x00;         /* initialization of Timer/Counter */
 172
 173                 /* Enable timer interrupt: Timer/Counter3 Overflow */
 174                 /* ATTENTION! TOIE3 is only on ETIMSK, not TIMSK */
 175                 ETIMSK |= BV(TOIE3);
 176
 177                 IRQ_RESTORE(flags);
 178         }
 179
 180         INLINE hptime_t timer_hw_hpread(void)
 181         {
 182                 return TCNT3;
 183         }
 184
 185 #else
 186         #error Unimplemented value for CONFIG_TIMER
 187 #endif /* CONFIG_TIMER */
 188