Go to most recent revision | Details | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 2012 | holgerb | 1 | /*####################################################################################### |
| 2 | Decodes the sbus protocol |
||
| 3 | #######################################################################################*/ |
||
| 4 | |||
| 5 | #include "sbus.h" |
||
| 6 | #include "main.h" |
||
| 7 | |||
| 8 | #if (defined(__AVR_ATmega1284__) || defined(__AVR_ATmega1284P__)) |
||
| 9 | unsigned char NewSBusData = 0, sBusBuffer[25]; |
||
| 10 | |||
| 11 | //############################################################################ |
||
| 12 | // USART1 initialisation from killagreg |
||
| 13 | void SbusUartInit(void) |
||
| 14 | //############################################################################ |
||
| 15 | { |
||
| 16 | // -- Start of USART1 initialisation for Spekturm seriell-mode |
||
| 17 | // USART1 Control and Status Register A, B, C and baud rate register |
||
| 18 | uint8_t sreg = SREG; |
||
| 19 | |||
| 20 | uint16_t ubrr = (uint16_t) ((uint32_t) SYSCLK/(8 * 100000) - 1); |
||
| 21 | |||
| 22 | // disable all interrupts before reconfiguration |
||
| 23 | cli(); |
||
| 24 | // disable RX-Interrupt |
||
| 25 | UCSR1B &= ~(1 << RXCIE1); |
||
| 26 | // disable TX-Interrupt |
||
| 27 | UCSR1B &= ~(1 << TXCIE1); |
||
| 28 | // disable DRE-Interrupt |
||
| 29 | UCSR1B &= ~(1 << UDRIE1); |
||
| 30 | // set direction of RXD1 and TXD1 pins |
||
| 31 | // set RXD1 (PD2) as an input pin |
||
| 32 | PORTD |= (1 << PORTD2); |
||
| 33 | DDRD &= ~(1 << DDD2); |
||
| 34 | |||
| 35 | // set TXD1 (PD3) as an output pin |
||
| 36 | PORTD |= (1 << PORTD3); |
||
| 37 | DDRD |= (1 << DDD3); |
||
| 38 | |||
| 39 | // USART0 Baud Rate Register |
||
| 40 | // set clock divider |
||
| 41 | UBRR1H = (uint8_t)(ubrr>>8); |
||
| 42 | UBRR1L = (uint8_t)ubrr; |
||
| 43 | // enable double speed operation |
||
| 44 | UCSR1A |= (1 << U2X1); |
||
| 45 | // enable receiver and transmitter |
||
| 46 | //UCSR1B = (1<<RXEN1)|(1<<TXEN1); |
||
| 47 | |||
| 48 | UCSR1B = (1<<RXEN1); |
||
| 49 | // set asynchronous mode |
||
| 50 | UCSR1C &= ~(1 << UMSEL11); |
||
| 51 | UCSR1C &= ~(1 << UMSEL10); |
||
| 52 | // parity |
||
| 53 | UCSR1C <= (1 << UPM11); // even |
||
| 54 | UCSR1C &= ~(1 << UPM10); |
||
| 55 | // stop bit |
||
| 56 | UCSR1C |= (1 << USBS1); // two |
||
| 57 | // 8-bit |
||
| 58 | UCSR1B &= ~(1 << UCSZ12); |
||
| 59 | UCSR1C |= (1 << UCSZ11); |
||
| 60 | UCSR1C |= (1 << UCSZ10); |
||
| 61 | // flush receive buffer explicit |
||
| 62 | while(UCSR1A & (1<<RXC1)) UDR1; |
||
| 63 | // enable RX-interrupts at the end |
||
| 64 | UCSR1B |= (1 << RXCIE1); |
||
| 65 | // -- End of USART1 initialisation |
||
| 66 | // restore global interrupt flags |
||
| 2029 | holgerb | 67 | sBusBuffer[23] |= 4; // This Bit contains the 'Signal loss' |
| 2012 | holgerb | 68 | SREG = sreg; |
| 69 | return; |
||
| 70 | } |
||
| 71 | |||
| 72 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
||
| 73 | #define MIN_FRAMEGAP 68 // 7ms |
||
| 74 | #define MAX_BYTEGAP 3 // 310us |
||
| 75 | |||
| 76 | //############################################################################ |
||
| 77 | // Is called by the uart interrupt |
||
| 78 | //############################################################################ |
||
| 79 | void SbusParser(unsigned char udr) |
||
| 80 | { |
||
| 81 | static unsigned char ptr = 0; |
||
| 82 | if(!SpektrumTimer && udr == 0x0f) // wait for the start |
||
| 83 | { |
||
| 84 | ptr = 0; |
||
| 2031 | holgerb | 85 | SpektrumTimer = 80; // 8ms gap |
| 86 | } |
||
| 2012 | holgerb | 87 | else |
| 88 | { |
||
| 89 | if(++ptr == 24) // last byte |
||
| 90 | { |
||
| 91 | NewSBusData = 1; |
||
| 92 | } |
||
| 93 | else |
||
| 94 | if(ptr > 24) ptr = 25; |
||
| 95 | else |
||
| 96 | { |
||
| 97 | sBusBuffer[ptr] = udr; // collect all bytes |
||
| 98 | } |
||
| 99 | } |
||
| 100 | } |
||
| 101 | |||
| 102 | void ProcessSBus(void) |
||
| 103 | { |
||
| 104 | static unsigned char load = 0; |
||
| 105 | unsigned char bitmask8 = 1, sbyte = 2, i, index = 1, process; |
||
| 106 | unsigned int bitmask11 = 256; |
||
| 107 | signed int signal = 0,tmp; |
||
| 108 | |||
| 109 | if(!(sBusBuffer[23] & 4)) // This Bit contains the 'Signal loss' |
||
| 110 | { |
||
| 111 | TIMSK1 &= ~_BV(ICIE1); // disable PPM-Input |
||
| 112 | if(EE_Parameter.FailsafeChannel == 0 || PPM_in[EE_Parameter.FailsafeChannel] < 100) // forces Failsafe if the receiver doesn't have 'signal loss' on Failsafe |
||
| 113 | { |
||
| 114 | if(SenderOkay < 200) SenderOkay += 10; else SenderOkay = 200; |
||
| 115 | } |
||
| 116 | signal = sBusBuffer[1]; |
||
| 117 | if(!load--) { process = (12*11 - 8); load = 2;} else process = (4*11 - 8); // lowers the processor load |
||
| 118 | for(i = 0; i < process; i++) // collect the single bits |
||
| 119 | { |
||
| 120 | if(sBusBuffer[sbyte] & bitmask8) signal |= bitmask11; |
||
| 121 | bitmask8 *= 2; |
||
| 122 | if(!bitmask8) |
||
| 123 | { |
||
| 124 | bitmask8 = 1; |
||
| 125 | sbyte++; |
||
| 126 | } |
||
| 127 | bitmask11 *= 2; |
||
| 128 | if(bitmask11 == 2048) |
||
| 129 | { |
||
| 130 | bitmask11 = 1; |
||
| 131 | signal = (signal-1024) / 5; // the resolution is higher than required |
||
| 132 | tmp = (3 * (PPM_in[index]) + signal) / 4; |
||
| 133 | if(tmp > signal+1) tmp--; else |
||
| 134 | if(tmp < signal-1) tmp++; |
||
| 135 | if(SenderOkay >= 195) PPM_diff[index] = ((tmp - PPM_in[index]) / 3) * 3; |
||
| 136 | else PPM_diff[index] = 0; |
||
| 137 | PPM_in[index] = tmp; |
||
| 138 | signal = 0; |
||
| 139 | index++; // next channel |
||
| 140 | } |
||
| 141 | } |
||
| 142 | NewPpmData = 0; // Null bedeutet: Neue Daten |
||
| 143 | } |
||
| 144 | NewSBusData = 0; |
||
| 145 | } |
||
| 146 | |||
| 147 | #endif |