avr/timer.c

   1 /*
   2  */
   3
   4
   5 #include "common.h"
   6
   7 //#include <avr/power.h>
   8 //#include <avr/pgmspace.h>
   9 #include <avr/interrupt.h>
  10 #include <util/atomic.h>
  11
  12 //#include <stdio.h>
  13
  14
  15 #include "timer.h"
  16
  17 /* timer interrupt/overflow counter */
  18 static volatile uint32_t timestamp;
  19
  20
  21 /*---------------------------------------------------------*/
  22 /* 1000Hz timer interrupt generated by OC1A                 */
  23 /*---------------------------------------------------------*/
  24
  25 ISR(TIMER1_COMPA_vect)
  26 {
  27         static int_fast8_t tick_10ms;
  28         int_fast8_t i;
  29
  30
  31         timestamp++;
  32
  33         i = tick_10ms + 1;
  34         if (i == 10) {
  35                 i = 0;
  36                 Stat |= S_10MS_TO;
  37
  38                 /* Drive timer procedure of low level disk I/O module */
  39                 //disk_timerproc();
  40         }
  41         tick_10ms = i;
  42
  43 }
  44
  45
  46
  47 /*--------------------------------------------------------------------------*/
  48
  49 #if 0
  50
  51 void do_10ms(void)
  52 {
  53                 if (to_counter)
  54                         to_counter--;
  55 }
  56
  57 #endif
  58
  59 /*--------------------------------------------------------------------------*/
  60
  61
  62 void timer_setup(void)
  63 {
  64
  65         /* Clock */
  66         CLKPR = _BV(CLKPCE);
  67         CLKPR = 0;
  68
  69         /* Timer */
  70
  71         OCR1A = F_CPU / 1000 - 1; // Timer1: 1000Hz interval (OC1A)
  72         TCCR1B = 0b00001001;
  73         TIMSK1 = _BV(OCIE1A); // Enable TC1.oca interrupt
  74 }
  75
  76
  77 uint32_t get_timer(uint32_t base)
  78 {
  79         uint32_t ret;
  80
  81         ATOMIC_BLOCK(ATOMIC_FORCEON)
  82         {
  83                 ret = timestamp;
  84         }
  85         return ret - base;
  86 }
  87