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 1.4  2006/07/19 12:56:26  bernie
  19  *#* Convert to new Doxygen style.
  20  *#*
  21  *#* Revision 1.3  2006/06/12 21:37:02  marco
  22  *#* implemented some commands (ver and sleep)
  23  *#*
  24  *#* Revision 1.2  2006/05/18 00:37:58  bernie
  25  *#* Don't include unneeded header hw.h.
  26  *#*
  27  *#* Revision 1.1  2005/07/19 07:28:36  bernie
  28  *#* Refactor to decouple timer ticks from milliseconds.
  29  *#*
  30  *#* Revision 1.1  2005/05/24 09:17:58  batt
  31  *#* Move drivers to top-level.
  32  *#*
  33  *#*/
  34 #include <drv/timer_avr.h>
  35 #include <cfg/macros.h> // BV()
  36
  37 #include <avr/interrupt.h>
  38 #include <avr/io.h>
  39
  40 /** HW dependent timer initialization  */
  41 #if (CONFIG_TIMER == TIMER_ON_OUTPUT_COMPARE0)
  42
  43         static void timer_hw_init(void)
  44         {
  45                 cpuflags_t flags;
  46                 IRQ_SAVE_DISABLE(flags);
  47
  48                 /* Reset Timer flags */
  49                 TIFR = BV(OCF0) | BV(TOV0);
  50
  51                 /* Setup Timer/Counter interrupt */
  52                 ASSR = 0x00;                  /* Internal system clock */
  53                 TCCR0 = BV(WGM01)             /* Clear on Compare match */
  54                         #if TIMER_PRESCALER == 64
  55                                 | BV(CS02)
  56                         #else
  57                                 #error Unsupported value of TIMER_PRESCALER
  58                         #endif
  59                 ;
  60                 TCNT0 = 0x00;                 /* Initialization of Timer/Counter */
  61                 OCR0 = OCR_DIVISOR;           /* Timer/Counter Output Compare Register */
  62
  63                 /* Enable timer interrupts: Timer/Counter2 Output Compare (OCIE2) */
  64                 TIMSK &= ~BV(TOIE0);
  65                 TIMSK |= BV(OCIE0);
  66
  67                 IRQ_RESTORE(flags);
  68         }
  69
  70         INLINE hptime_t timer_hw_hpread(void)
  71         {
  72                 return TCNT0;
  73         }
  74
  75 #elif (CONFIG_TIMER == TIMER_ON_OVERFLOW1)
  76
  77         static void timer_hw_init(void)
  78         {
  79                 cpuflags_t flags;
  80                 IRQ_SAVE_DISABLE(flags);
  81
  82                 /* Reset Timer overflow flag */
  83                 TIFR |= BV(TOV1);
  84
  85                 /* Fast PWM mode, 9 bit, 24 kHz, no prescaling. */
  86                 #if (TIMER_PRESCALER == 1) && (TIMER_HW_BITS == 9)
  87                         TCCR1A |= BV(WGM11);
  88                         TCCR1A &= ~BV(WGM10);
  89                         TCCR1B |= BV(WGM12) | BV(CS10);
  90                         TCCR1B &= ~(BV(WGM13) | BV(CS11) | BV(CS12));
  91                 /* Fast PWM mode, 8 bit, 24 kHz, no prescaling. */
  92                 #elif (TIMER_PRESCALER == 1) && (TIMER_HW_BITS == 8)
  93                         TCCR1A |= BV(WGM10);
  94                         TCCR1A &= ~BV(WGM11);
  95                         TCCR1B |= BV(WGM12) | BV(CS10);
  96                         TCCR1B &= ~(BV(WGM13) | BV(CS11) | BV(CS12));
  97                 #else
  98                         #error Unsupported value of TIMER_PRESCALER or TIMER_HW_BITS
  99                 #endif
 100
 101                 TCNT1 = 0x00;         /* initialization of Timer/Counter */
 102
 103                 /* Enable timer interrupt: Timer/Counter1 Overflow */
 104                 TIMSK |= BV(TOIE1);
 105
 106                 IRQ_RESTORE(flags);
 107         }
 108
 109         INLINE hptime_t timer_hw_hpread(void)
 110         {
 111                 return TCNT1;
 112         }
 113
 114 #elif (CONFIG_TIMER == TIMER_ON_OUTPUT_COMPARE2)
 115
 116         static void timer_hw_init(void)
 117         {
 118                 cpuflags_t flags;
 119                 IRQ_SAVE_DISABLE(flags);
 120
 121                 /* Reset Timer flags */
 122                 TIFR = BV(OCF2) | BV(TOV2);
 123
 124                 /* Setup Timer/Counter interrupt */
 125                 TCCR2 = BV(WGM21)
 126                         #if TIMER_PRESCALER == 64
 127                                 | BV(CS21) | BV(CS20)
 128                         #else
 129                                 #error Unsupported value of TIMER_PRESCALER
 130                         #endif
 131                 ;
 132                 /* Clear on Compare match & prescaler = 64, internal sys clock.
 133                    When changing prescaler change TIMER_HW_HPTICKS_PER_SEC too */
 134                 TCNT2 = 0x00;         /* initialization of Timer/Counter */
 135                 OCR2 = OCR_DIVISOR;   /* Timer/Counter Output Compare Register */
 136
 137                 /* Enable timer interrupts: Timer/Counter2 Output Compare (OCIE2) */
 138                 TIMSK &= ~BV(TOIE2);
 139                 TIMSK |= BV(OCIE2);
 140
 141                 IRQ_RESTORE(flags);
 142         }
 143
 144         INLINE hptime_t timer_hw_hpread(void)
 145         {
 146                 return TCNT2;
 147         }
 148 #elif (CONFIG_TIMER == TIMER_ON_OVERFLOW3)
 149
 150         static void timer_hw_init(void)
 151         {
 152                 cpuflags_t flags;
 153                 IRQ_SAVE_DISABLE(flags);
 154
 155                 /* Reset Timer overflow flag */
 156                 TIFR |= BV(TOV3);
 157
 158                 /* Fast PWM mode, 9 bit, 24 kHz, no prescaling. */
 159                 #if (TIMER_PRESCALER == 1) && (TIMER_HW_BITS == 9)
 160                         TCCR3A |= BV(WGM31);
 161                         TCCR3A &= ~BV(WGM30);
 162                         TCCR3B |= BV(WGM32) | BV(CS30);
 163                         TCCR3B &= ~(BV(WGM33) | BV(CS31) | BV(CS32));
 164                 /* Fast PWM mode, 8 bit, 24 kHz, no prescaling. */
 165                 #elif (TIMER_PRESCALER == 1) && (TIMER_HW_BITS == 8)
 166                         TCCR3A |= BV(WGM30);
 167                         TCCR3A &= ~BV(WGM31);
 168                         TCCR3B |= BV(WGM32) | BV(CS30);
 169                         TCCR3B &= ~(BV(WGM33) | BV(CS31) | BV(CS32));
 170                 #else
 171                         #error Unsupported value of TIMER_PRESCALER or TIMER_HW_BITS
 172                 #endif
 173
 174                 TCNT3 = 0x00;         /* initialization of Timer/Counter */
 175
 176                 /* Enable timer interrupt: Timer/Counter3 Overflow */
 177                 /* ATTENTION! TOIE3 is only on ETIMSK, not TIMSK */
 178                 ETIMSK |= BV(TOIE3);
 179
 180                 IRQ_RESTORE(flags);
 181         }
 182
 183         INLINE hptime_t timer_hw_hpread(void)
 184         {
 185                 return TCNT3;
 186         }
 187
 188 #else
 189         #error Unimplemented value for CONFIG_TIMER
 190 #endif /* CONFIG_TIMER */
 191