root / trunk / code / projects / colonet / utilities / robot_wireless_relay / time.c @ 402
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1 | 13 | emarinel | /*
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2 | time.c
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3 | anything that requires a delay
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4 | mostly delay_ms
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5 | |||
6 | author: Robotics Club, Colony Project
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7 | |||
8 | */
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9 | #include <avr/interrupt.h> |
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10 | #include <util/delay.h> |
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11 | #include <time.h> |
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12 | #include <help.h> |
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13 | #include <serial.h> |
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14 | |||
15 | static volatile int _rtc_val = 0; |
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16 | static void (*_rtc_f)(void) = 0; |
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17 | |||
18 | /*
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19 | delay_ms
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20 | |||
21 | delays for ms milliseconds
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22 | |||
23 | accuracy is unknown (off by tens of nanoseconds every 15 ms)
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24 | */
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25 | void delay_ms(int ms) |
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26 | { |
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27 | for(; ms > 15; ms-=15) |
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28 | _delay_ms(15);
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29 | _delay_ms(ms); |
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30 | } |
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31 | |||
32 | void pause_ms(int ms) |
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33 | { |
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34 | delay_ms(ms); |
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35 | } |
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36 | |||
37 | void pause(int ms) |
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38 | { |
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39 | delay_ms(ms); |
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40 | } |
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41 | |||
42 | void sleep_ms(int ms) |
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43 | { |
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44 | delay_ms(ms); |
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45 | } |
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46 | |||
47 | void sleep(int ms) |
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48 | { |
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49 | delay_ms(ms); |
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50 | } |
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51 | |||
52 | /*
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53 | void rtc_init(void)
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54 | call this function to start the real time timer
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55 | use rtc() to get the time value and rtc_resest() to reset
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56 | |||
57 | requires global interrupts to be enabled for proper use
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58 | (I bit of SREG register should be set)
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59 | |||
60 | uses TIMER0 on asynchronous mode
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61 | */
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62 | |||
63 | void rtc_init(int prescale_opt, unsigned char ocr_val, void (*rtc_func)(void)){ |
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64 | int mask = _BV(TCN0UB) + _BV(OCR0UB) + _BV(TCR0UB);
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65 | char tmp;
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66 | |||
67 | TIMSK &= ~(_BV(OCIE0) + _BV(TOIE0)); //1. disable interrupts
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68 | ASSR |= _BV(AS0); //2. selecting clock source (external)
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69 | |||
70 | //3. writing new values to TCCR, TCNT, OCR
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71 | TCNT0 = 0;
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72 | OCR0 = ocr_val; |
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73 | TCCR0 = (0x01 << 3) + (prescale_opt & 0x07); //setting CTC mode, prescaler is lowest 3 bits |
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74 | |||
75 | //4. waiting for busy bits to clear
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76 | tmp = ASSR; |
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77 | while( tmp & mask ){
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78 | tmp = ASSR; |
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79 | } |
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80 | |||
81 | TIFR &= ~(_BV(OCF0) + _BV(TOV0)); //5. clearing the interrupt flags
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82 | TIMSK |= _BV(OCIE0); // + _BV(TOIE0); //6. enabling interrupts
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83 | |||
84 | _rtc_f = rtc_func; |
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85 | } |
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86 | |||
87 | int rtc(void){ |
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88 | return _rtc_val;
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89 | } |
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90 | |||
91 | void rtc_reset(void){ |
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92 | _rtc_val = 0;
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93 | } |
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94 | |||
95 | SIGNAL (SIG_OUTPUT_COMPARE0){ |
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96 | _rtc_val++; |
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97 | |||
98 | if(_rtc_f != 0) |
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99 | _rtc_f(); |
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100 | } |