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Rev | Author | Line No. | Line |
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2012 | holgerb | 1 | /*####################################################################################### |
2 | Decodes the sbus protocol |
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3 | #######################################################################################*/ |
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4 | |||
5 | #include "sbus.h" |
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6 | #include "main.h" |
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7 | |||
8 | #if (defined(__AVR_ATmega1284__) || defined(__AVR_ATmega1284P__)) |
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9 | unsigned char NewSBusData = 0, sBusBuffer[25]; |
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10 | |||
11 | //############################################################################ |
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12 | // USART1 initialisation from killagreg |
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13 | void SbusUartInit(void) |
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14 | //############################################################################ |
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15 | { |
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16 | // -- Start of USART1 initialisation for Spekturm seriell-mode |
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17 | // USART1 Control and Status Register A, B, C and baud rate register |
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18 | uint8_t sreg = SREG; |
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19 | |||
20 | uint16_t ubrr = (uint16_t) ((uint32_t) SYSCLK/(8 * 100000) - 1); |
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21 | |||
22 | // disable all interrupts before reconfiguration |
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23 | cli(); |
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24 | // disable RX-Interrupt |
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25 | UCSR1B &= ~(1 << RXCIE1); |
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26 | // disable TX-Interrupt |
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27 | UCSR1B &= ~(1 << TXCIE1); |
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28 | // disable DRE-Interrupt |
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29 | UCSR1B &= ~(1 << UDRIE1); |
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30 | // set direction of RXD1 and TXD1 pins |
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31 | // set RXD1 (PD2) as an input pin |
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32 | PORTD |= (1 << PORTD2); |
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33 | DDRD &= ~(1 << DDD2); |
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34 | |||
35 | // set TXD1 (PD3) as an output pin |
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36 | PORTD |= (1 << PORTD3); |
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37 | DDRD |= (1 << DDD3); |
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38 | |||
39 | // USART0 Baud Rate Register |
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40 | // set clock divider |
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41 | UBRR1H = (uint8_t)(ubrr>>8); |
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42 | UBRR1L = (uint8_t)ubrr; |
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43 | // enable double speed operation |
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44 | UCSR1A |= (1 << U2X1); |
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45 | // enable receiver and transmitter |
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46 | //UCSR1B = (1<<RXEN1)|(1<<TXEN1); |
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47 | |||
48 | UCSR1B = (1<<RXEN1); |
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49 | // set asynchronous mode |
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50 | UCSR1C &= ~(1 << UMSEL11); |
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51 | UCSR1C &= ~(1 << UMSEL10); |
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52 | // parity |
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53 | UCSR1C <= (1 << UPM11); // even |
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54 | UCSR1C &= ~(1 << UPM10); |
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55 | // stop bit |
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56 | UCSR1C |= (1 << USBS1); // two |
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57 | // 8-bit |
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58 | UCSR1B &= ~(1 << UCSZ12); |
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59 | UCSR1C |= (1 << UCSZ11); |
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60 | UCSR1C |= (1 << UCSZ10); |
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61 | // flush receive buffer explicit |
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62 | while(UCSR1A & (1<<RXC1)) UDR1; |
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63 | // enable RX-interrupts at the end |
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64 | UCSR1B |= (1 << RXCIE1); |
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65 | // -- End of USART1 initialisation |
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66 | // restore global interrupt flags |
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2029 | holgerb | 67 | sBusBuffer[23] |= 4; // This Bit contains the 'Signal loss' |
2012 | holgerb | 68 | SREG = sreg; |
69 | return; |
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70 | } |
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71 | |||
72 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
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73 | #define MIN_FRAMEGAP 68 // 7ms |
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74 | #define MAX_BYTEGAP 3 // 310us |
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75 | |||
76 | //############################################################################ |
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77 | // Is called by the uart interrupt |
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78 | //############################################################################ |
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79 | void SbusParser(unsigned char udr) |
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80 | { |
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81 | static unsigned char ptr = 0; |
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82 | if(!SpektrumTimer && udr == 0x0f) // wait for the start |
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83 | { |
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84 | ptr = 0; |
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85 | } |
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86 | else |
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87 | { |
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88 | if(++ptr == 24) // last byte |
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89 | { |
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90 | NewSBusData = 1; |
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91 | } |
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92 | else |
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93 | if(ptr > 24) ptr = 25; |
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94 | else |
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95 | { |
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96 | sBusBuffer[ptr] = udr; // collect all bytes |
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97 | } |
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98 | } |
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99 | SpektrumTimer = 100; // 10ms gap |
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100 | } |
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101 | |||
102 | void ProcessSBus(void) |
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103 | { |
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104 | static unsigned char load = 0; |
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105 | unsigned char bitmask8 = 1, sbyte = 2, i, index = 1, process; |
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106 | unsigned int bitmask11 = 256; |
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107 | signed int signal = 0,tmp; |
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108 | |||
109 | if(!(sBusBuffer[23] & 4)) // This Bit contains the 'Signal loss' |
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110 | { |
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111 | TIMSK1 &= ~_BV(ICIE1); // disable PPM-Input |
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112 | if(EE_Parameter.FailsafeChannel == 0 || PPM_in[EE_Parameter.FailsafeChannel] < 100) // forces Failsafe if the receiver doesn't have 'signal loss' on Failsafe |
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113 | { |
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114 | if(SenderOkay < 200) SenderOkay += 10; else SenderOkay = 200; |
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115 | } |
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116 | signal = sBusBuffer[1]; |
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117 | if(!load--) { process = (12*11 - 8); load = 2;} else process = (4*11 - 8); // lowers the processor load |
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118 | for(i = 0; i < process; i++) // collect the single bits |
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119 | { |
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120 | if(sBusBuffer[sbyte] & bitmask8) signal |= bitmask11; |
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121 | bitmask8 *= 2; |
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122 | if(!bitmask8) |
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123 | { |
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124 | bitmask8 = 1; |
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125 | sbyte++; |
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126 | } |
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127 | bitmask11 *= 2; |
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128 | if(bitmask11 == 2048) |
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129 | { |
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130 | bitmask11 = 1; |
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131 | signal = (signal-1024) / 5; // the resolution is higher than required |
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132 | tmp = (3 * (PPM_in[index]) + signal) / 4; |
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133 | if(tmp > signal+1) tmp--; else |
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134 | if(tmp < signal-1) tmp++; |
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135 | if(SenderOkay >= 195) PPM_diff[index] = ((tmp - PPM_in[index]) / 3) * 3; |
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136 | else PPM_diff[index] = 0; |
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137 | PPM_in[index] = tmp; |
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138 | signal = 0; |
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139 | index++; // next channel |
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140 | } |
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141 | } |
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142 | NewPpmData = 0; // Null bedeutet: Neue Daten |
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143 | } |
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144 | NewSBusData = 0; |
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145 | } |
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146 | |||
147 | #endif |