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