[16a384cf] | 1 | /* Timer_init() |
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| 2 | * |
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| 3 | * This routine initializes the timer on the FORCE CPU-386 board. |
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| 4 | * |
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| 5 | * Input parameters: NONE |
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| 6 | * |
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| 7 | * Output parameters: NONE |
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| 8 | * |
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| 9 | * NOTE: This routine will not work if the optimizer is enabled |
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| 10 | * for some compilers. The multiple writes to the Z8036 |
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| 11 | * may be optimized away. |
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| 12 | * |
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| 13 | * It is important that the timer start/stop overhead be |
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| 14 | * determined when porting or modifying this code. |
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| 15 | * |
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[08311cc3] | 16 | * COPYRIGHT (c) 1989-1999. |
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[16a384cf] | 17 | * On-Line Applications Research Corporation (OAR). |
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| 18 | * |
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| 19 | * The license and distribution terms for this file may be |
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| 20 | * found in the file LICENSE in this distribution or at |
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| 21 | * http://www.OARcorp.com/rtems/license.html. |
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| 22 | * |
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| 23 | * $Id$ |
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| 24 | */ |
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| 25 | |
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| 26 | |
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| 27 | #include <rtems.h> |
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| 28 | #include <bsp.h> |
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| 29 | #include <stdlib.h> |
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| 30 | |
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| 31 | volatile rtems_unsigned32 Ttimer_val; /* Updated from ISR!!! */ |
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| 32 | rtems_boolean Timer_driver_Find_average_overhead; |
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| 33 | |
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| 34 | extern void timerisr(); |
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| 35 | |
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| 36 | /* |
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| 37 | * Number of us per timer interrupt. Note: 1 us == 1 tick. |
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| 38 | */ |
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| 39 | |
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| 40 | #define US_PER_ISR 250 |
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| 41 | |
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| 42 | void TimerOn(const rtems_raw_irq_connect_data* used) |
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| 43 | { |
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| 44 | |
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| 45 | Ttimer_val = 0; /* clear timer ISR count */ |
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| 46 | |
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| 47 | /* Select timer, stay in mode 0 */ |
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| 48 | outport_byte (TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN); |
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| 49 | |
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| 50 | /* Set to 250 usec interval */ |
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| 51 | outport_byte (TIMER_CNTR0, US_PER_ISR & 0xFF ); |
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| 52 | outport_byte (TIMER_CNTR0, (US_PER_ISR >> 8) & 0xFF ); |
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| 53 | |
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| 54 | /* Enable all timers */ |
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| 55 | outport_byte (TIMER_CONFIG, 0x00); |
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| 56 | |
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| 57 | /* |
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| 58 | * enable interrrupt at i8259 level |
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| 59 | */ |
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| 60 | BSP_irq_enable_at_i8259s(used->idtIndex - BSP_IRQ_VECTOR_BASE); |
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| 61 | } |
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| 62 | |
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| 63 | static int TimerIsOn (const rtems_raw_irq_connect_data *used) |
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| 64 | { |
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| 65 | return BSP_irq_enabled_at_i8259s(used->idtIndex - BSP_IRQ_VECTOR_BASE); |
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| 66 | } |
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| 67 | |
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| 68 | void TimerOff(const rtems_raw_irq_connect_data* used) |
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| 69 | { |
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| 70 | /* Disable all timers */ |
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| 71 | outport_byte (TIMER_CONFIG, 0x80); |
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| 72 | |
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| 73 | /* |
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| 74 | * disable interrrupt at i8259 level |
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| 75 | */ |
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| 76 | BSP_irq_disable_at_i8259s(used->idtIndex - BSP_IRQ_VECTOR_BASE); |
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| 77 | /* reset timer mode to standard (DOS) value */ |
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| 78 | } |
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| 79 | |
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| 80 | static rtems_raw_irq_connect_data timer_raw_irq_data = { |
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| 81 | BSP_PERIODIC_TIMER + BSP_IRQ_VECTOR_BASE, |
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| 82 | timerisr, |
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| 83 | TimerOn, |
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| 84 | TimerOff, |
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| 85 | TimerIsOn |
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| 86 | }; |
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| 87 | |
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| 88 | static rtems_raw_irq_connect_data old_raw_irq_data = { |
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| 89 | BSP_PERIODIC_TIMER + BSP_IRQ_VECTOR_BASE, |
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| 90 | }; |
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| 91 | |
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| 92 | void Timer_exit() |
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| 93 | { |
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| 94 | if (!i386_delete_idt_entry(&timer_raw_irq_data)) { |
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| 95 | printk("Timer_exit:Timer raw handler removal failed\n"); |
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| 96 | rtems_fatal_error_occurred(1); |
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| 97 | } |
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| 98 | } |
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| 99 | |
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| 100 | void Timer_initialize(void) |
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| 101 | { |
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| 102 | |
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| 103 | static rtems_boolean First = TRUE; |
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| 104 | |
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| 105 | if (First) |
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| 106 | { |
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| 107 | First = FALSE; |
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| 108 | |
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| 109 | if (!i386_get_current_idt_entry (&old_raw_irq_data)) { |
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| 110 | printk("Timer_initialize: failed to get old raw irq entry.\n"); |
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| 111 | rtems_fatal_error_occurred(1); |
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| 112 | } |
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| 113 | |
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| 114 | if (!i386_delete_idt_entry (&old_raw_irq_data)) { |
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| 115 | printk("Timer_initialize: failed to delete old raw irq entry.\n"); |
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| 116 | rtems_fatal_error_occurred(1); |
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| 117 | } |
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| 118 | |
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| 119 | atexit(Timer_exit); /* Try not to hose the system at exit. */ |
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| 120 | if (!i386_set_idt_entry (&timer_raw_irq_data)) { |
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| 121 | printk("Timer_initialize: raw handler installation failed.\n"); |
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| 122 | rtems_fatal_error_occurred(1); |
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| 123 | } |
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| 124 | } |
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| 125 | |
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| 126 | /* wait for ISR to be called at least once */ |
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| 127 | Ttimer_val = 0; |
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| 128 | while (Ttimer_val == 0) |
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| 129 | continue; |
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| 130 | Ttimer_val = 0; |
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| 131 | } |
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| 132 | |
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| 133 | |
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| 134 | #define AVG_OVERHEAD 3 /* It typically takes 3.0 microseconds */ |
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| 135 | /* (3 ticks) to start/stop the timer. */ |
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| 136 | #define LEAST_VALID 4 /* Don't trust a value lower than this */ |
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| 137 | |
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| 138 | int Read_timer(void) |
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| 139 | { |
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| 140 | register rtems_unsigned32 clicks, total; |
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| 141 | register rtems_unsigned8 lsb, msb; |
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| 142 | |
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| 143 | /* latch the count */ |
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| 144 | outport_byte (TIMER_MODE, TIMER_SEL0|TIMER_LATCH ); |
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| 145 | |
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| 146 | /* read the count */ |
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| 147 | inport_byte (TIMER_CNTR0, lsb ); |
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| 148 | inport_byte (TIMER_CNTR0, msb ); |
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| 149 | |
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| 150 | /* |
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| 151 | * Timer ISR increments Ttimer_val every US_PER_ISR clock ticks, |
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| 152 | * where 1 tick == 1 us. Below, 'click' is in microseconds. |
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| 153 | * |
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| 154 | * This assumes the timer input clocks are sourced from the system's |
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| 155 | * prescaled clock (PSCLK), which is set to be at 1MHz. |
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| 156 | */ |
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| 157 | clicks = (msb << 8) | lsb; |
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| 158 | total = Ttimer_val * US_PER_ISR + (US_PER_ISR - clicks); |
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| 159 | |
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| 160 | if ( Timer_driver_Find_average_overhead == 1 ) |
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| 161 | return total; /* in one microsecond units */ |
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| 162 | else if ( total < LEAST_VALID ) |
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| 163 | return 0; /* below timer resolution */ |
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| 164 | else |
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| 165 | return (total - AVG_OVERHEAD); |
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| 166 | } |
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| 167 | |
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| 168 | rtems_status_code Empty_function( void ) |
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| 169 | { |
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| 170 | return RTEMS_SUCCESSFUL; |
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| 171 | } |
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| 172 | |
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| 173 | void Set_find_average_overhead( |
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| 174 | rtems_boolean find_flag |
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| 175 | ) |
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| 176 | { |
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| 177 | Timer_driver_Find_average_overhead = find_flag; |
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| 178 | } |
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| 179 | |
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| 180 | /* |
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| 181 | * Wait_X_ms: a delay loop used by the network driver... |
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| 182 | */ |
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| 183 | |
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| 184 | #define SLOW_DOWN_IO 0x80 /* I/O port which does nothing */ |
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| 185 | #define LOOP1MS 320 /* Just a guess.... */ |
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| 186 | |
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| 187 | void Wait_X_ms (unsigned timeToWait) |
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| 188 | { |
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| 189 | unsigned i, j; |
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| 190 | |
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| 191 | for (j=0; j<timeToWait; j++) |
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| 192 | for (i=0; i<LOOP1MS; i++) |
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| 193 | outport_byte (SLOW_DOWN_IO, 0); |
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| 194 | } |
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