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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 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 |