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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 51 | johboh | 1 | /********************************************************************* |
| 2 | * |
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| 3 | * Ticker service |
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| 4 | * |
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| 5 | ********************************************************************* |
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| 6 | * FileName: Tick.c |
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| 7 | * |
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| 8 | * Author Date Comment |
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| 9 | *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
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| 10 | * Johan Böhlin 21-10-06 Original (Rev 1.0) |
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| 11 | ********************************************************************/ |
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| 12 | |||
| 13 | #define TICK_INCLUDE |
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| 14 | |||
| 15 | #include "..\Include\Tick.h" |
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| 16 | #include "..\Include\Compiler.h" |
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| 17 | |||
| 18 | #define TICK_TEMP_VALUE_1 ((INSTR_FREQ) / (TICKS_PER_SECOND * TICK_PRESCALE_VALUE)) |
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| 19 | |||
| 20 | #if TICK_TEMP_VALUE_1 > 60000 |
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| 21 | #error TICK_PER_SECOND value cannot be programmed with current CLOCK_FREQ |
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| 22 | #error Either lower TICK_PER_SECOND or manually configure the Timer |
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| 23 | #endif |
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| 24 | |||
| 25 | #define TICK_TEMP_VALUE (65535 - TICK_TEMP_VALUE_1) |
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| 26 | |||
| 27 | #define TICK_COUNTER_HIGH ((TICK_TEMP_VALUE >> 8) & 0xff) |
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| 28 | #define TICK_COUNTER_LOW (TICK_TEMP_VALUE & 0xff) |
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| 29 | |||
| 30 | #if (TICK_PRESCALE_VALUE == 2) |
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| 31 | #define TIMER_PRESCALE (0) |
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| 32 | #elif ( TICK_PRESCALE_VALUE == 4 ) |
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| 33 | #define TIMER_PRESCALE (1) |
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| 34 | #elif ( TICK_PRESCALE_VALUE == 8 ) |
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| 35 | #define TIMER_PRESCALE (2) |
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| 36 | #elif ( TICK_PRESCALE_VALUE == 16 ) |
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| 37 | #define TIMER_PRESCALE (3) |
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| 38 | #elif ( TICK_PRESCALE_VALUE == 32 ) |
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| 39 | #define TIMER_PRESCALE (4) |
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| 40 | #elif ( TICK_PRESCALE_VALUE == 64 ) |
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| 41 | #define TIMER_PRESCALE (5) |
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| 42 | #elif ( TICK_PRESCALE_VALUE == 128 ) |
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| 43 | #define TIMER_PRESCALE (6) |
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| 44 | #elif ( TICK_PRESCALE_VALUE == 256 ) |
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| 45 | #define TIMER_PRESCALE (7) |
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| 46 | #else |
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| 47 | #error Invalid TICK_PRESCALE_VALUE specified. |
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| 48 | #endif |
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| 49 | |||
| 50 | |||
| 51 | TICK TickCount = 0; // 10ms/unit |
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| 52 | |||
| 53 | |||
| 54 | |||
| 55 | /* |
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| 56 | * Function: TickInit |
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| 57 | * |
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| 58 | * Input: none |
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| 59 | * Output: Tick manager is initialized. |
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| 60 | * Pre-conditions: TickInit |
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| 61 | * Affects: none |
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| 62 | * Depends: none |
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| 63 | */ |
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| 64 | #define PERIOD (INSTR_FREQ/256/1000)*TICK_PERIOD_MS |
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| 65 | void tickInit(void) |
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| 66 | { |
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| 67 | // Start the timer. |
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| 68 | TMR0L = TICK_COUNTER_LOW; |
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| 69 | TMR0H = TICK_COUNTER_HIGH; |
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| 70 | |||
| 71 | // 16-BIT, internal timer, PSA set to 1:256 |
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| 72 | T0CON = 0b00000000 | TIMER_PRESCALE; |
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| 73 | |||
| 74 | // Start the timer. |
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| 75 | T0CONbits.TMR0ON = 1; |
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| 76 | |||
| 77 | INTCONbits.TMR0IF = 1; |
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| 78 | INTCONbits.TMR0IE = 1; |
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| 79 | } |
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| 80 | |||
| 81 | /* |
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| 82 | * Function: TickGet |
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| 83 | * |
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| 84 | * Input: none |
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| 85 | * Output: Current tick value is given, 1 tick represents approximately 10ms |
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| 86 | * Pre-conditions: TickInit |
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| 87 | * Affects: none |
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| 88 | * Depends: none |
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| 89 | */ |
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| 90 | TICK tickGet(void) |
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| 91 | { |
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| 92 | return TickCount; |
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| 93 | } |
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| 94 | |||
| 95 | |||
| 96 | /* |
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| 97 | * Function: tickUpdate |
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| 98 | * |
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| 99 | * Input: none |
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| 100 | * Output: none |
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| 101 | * Pre-conditions: TickInit |
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| 102 | * Affects: none |
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| 103 | * Depends: none |
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| 104 | */ |
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| 105 | void tickUpdate(void) |
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| 106 | { |
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| 107 | if(INTCONbits.TMR0IF) |
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| 108 | { |
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| 109 | TMR0H = TICK_COUNTER_HIGH; |
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| 110 | TMR0L = TICK_COUNTER_LOW; |
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| 111 | |||
| 112 | TickCount++; |
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| 113 | |||
| 114 | INTCONbits.TMR0IF = 0; |
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| 115 | } |
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| 116 | } |