root / scout_avr / src / Atmega128rfa1.cpp @ f115416e
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1 | 88fb3a79 | Tom Mullins | #include "Atmega128rfa1.h" |
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2 | |||
3 | extern "C" |
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4 | { |
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5 | #include <avr/io.h> |
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6 | #include <avr/interrupt.h> |
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7 | 49090532 | Tom Mullins | void __cxa_pure_virtual(void) {} |
8 | 88fb3a79 | Tom Mullins | } |
9 | |||
10 | unsigned long millis; |
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11 | |||
12 | 20f94878 | Tom Mullins | int rx_start = 0, rx_end = 0; |
13 | char rx_buffer[RX_BUFFER_SIZE];
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14 | |||
15 | 88fb3a79 | Tom Mullins | Atmega128rfa1::Atmega128rfa1() |
16 | { |
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17 | } |
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18 | |||
19 | ISR(TIMER0_COMPA_vect) |
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20 | { |
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21 | millis++; |
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22 | } |
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23 | |||
24 | 807483bf | Tom Mullins | ISR(USART0_RX_vect) |
25 | 20f94878 | Tom Mullins | { |
26 | char data = UDR0;
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27 | cf115e3d | Tom Mullins | if (rx_end == rx_start-1 || (rx_start == 0 && rx_end == RX_BUFFER_SIZE-1)) |
28 | 20f94878 | Tom Mullins | { |
29 | // TODO warn of buffer overflow?
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30 | } |
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31 | else
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32 | { |
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33 | rx_buffer[rx_end] = data; |
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34 | rx_end++; |
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35 | if (rx_end == RX_BUFFER_SIZE)
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36 | rx_end = 0;
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37 | } |
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38 | } |
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39 | |||
40 | 88fb3a79 | Tom Mullins | void Atmega128rfa1::init()
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41 | { |
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42 | // === init serial ===
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43 | 49090532 | Tom Mullins | // baud = F_CPU / (16 (UBRR + 1))
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44 | 1c3c96ce | Tom Mullins | uint16_t ubrr = F_CPU / 16 / BAUD_RATE - 1; |
45 | 49090532 | Tom Mullins | UBRR0H = ubrr >> 8;
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46 | UBRR0L = ubrr; |
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47 | 88fb3a79 | Tom Mullins | // UMSEL0 = 0, asynchronous usart
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48 | // UPM0 = 0, parity check disabled
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49 | // USBS0 = 0, 1 stop bit
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50 | // UCSZ0 = 3, 8-bit
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51 | 20f94878 | Tom Mullins | UCSR0B = _BV(RXCIE0) | _BV(RXEN0) | _BV(TXEN0); |
52 | 88fb3a79 | Tom Mullins | UCSR0C = _BV(UCSZ01) | _BV(UCSZ00); |
53 | |||
54 | // === init time ===
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55 | // COM0x = 0, pin OC0x not used
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56 | // WGM0 = 2, clear timer on compare match, TOP = OCRA
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57 | // CS0 = 3, 64 prescaler
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58 | TCCR0A = _BV(WGM01); |
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59 | TCCR0B = _BV(CS01) | _BV(CS00); |
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60 | // enable interrupt on compare match A
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61 | TIMSK0 = _BV(OCIE0A); |
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62 | f115416e | Tom Mullins | // 1 ms with 1/64 prescaler
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63 | OCR0A = F_CPU / 1000 / 64; |
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64 | 88fb3a79 | Tom Mullins | millis = 0;
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65 | 20f94878 | Tom Mullins | |
66 | sei(); |
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67 | 88fb3a79 | Tom Mullins | } |
68 | |||
69 | int Atmega128rfa1::read()
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70 | { |
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71 | cf115e3d | Tom Mullins | cli(); |
72 | 20f94878 | Tom Mullins | if (rx_start == rx_end)
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73 | return -1; |
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74 | else
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75 | { |
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76 | int ret = rx_buffer[rx_start];
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77 | rx_start++; |
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78 | if (rx_start == RX_BUFFER_SIZE)
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79 | rx_start = 0;
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80 | return ret;
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81 | } |
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82 | cf115e3d | Tom Mullins | sei(); |
83 | 88fb3a79 | Tom Mullins | } |
84 | |||
85 | void Atmega128rfa1::write(uint8_t* data, int length) |
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86 | { |
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87 | // TODO make this non-blocking with a tx buffer
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88 | int i;
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89 | for (i = 0; i < length; i++) |
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90 | { |
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91 | while (!(UCSR0A & _BV(UDRE0)));
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92 | UDR0 = data[i]; |
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93 | } |
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94 | } |
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95 | |||
96 | unsigned long Atmega128rfa1::time() |
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97 | { |
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98 | unsigned long ret; |
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99 | cli(); |
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100 | ret = millis; |
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101 | sei(); |
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102 | return ret;
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103 | } |