Go to most recent revision |
Blame |
Last modification |
View Log
| RSS feed
/*#######################################################################################
Decodes the sbus protocol
#######################################################################################*/
#include "sbus.h"
#include "main.h"
#if (defined(__AVR_ATmega1284__) || defined(__AVR_ATmega1284P__))
unsigned char NewSBusData = 0, sBusBuffer[25];
//############################################################################
// USART1 initialisation from killagreg
void SbusUartInit(void)
//############################################################################
{
// -- Start of USART1 initialisation for Spekturm seriell-mode
// USART1 Control and Status Register A, B, C and baud rate register
uint8_t sreg = SREG;
uint16_t ubrr = (uint16_t) ((uint32_t) SYSCLK/(8 * 100000) - 1);
// disable all interrupts before reconfiguration
cli();
// disable RX-Interrupt
UCSR1B &= ~(1 << RXCIE1);
// disable TX-Interrupt
UCSR1B &= ~(1 << TXCIE1);
// disable DRE-Interrupt
UCSR1B &= ~(1 << UDRIE1);
// set direction of RXD1 and TXD1 pins
// set RXD1 (PD2) as an input pin
PORTD |= (1 << PORTD2);
DDRD &= ~(1 << DDD2);
// set TXD1 (PD3) as an output pin
PORTD |= (1 << PORTD3);
DDRD |= (1 << DDD3);
// USART0 Baud Rate Register
// set clock divider
UBRR1H = (uint8_t)(ubrr>>8);
UBRR1L = (uint8_t)ubrr;
// enable double speed operation
UCSR1A |= (1 << U2X1);
// enable receiver and transmitter
//UCSR1B = (1<<RXEN1)|(1<<TXEN1);
UCSR1B = (1<<RXEN1);
// set asynchronous mode
UCSR1C &= ~(1 << UMSEL11);
UCSR1C &= ~(1 << UMSEL10);
// parity
UCSR1C <= (1 << UPM11); // even
UCSR1C &= ~(1 << UPM10);
// stop bit
UCSR1C |= (1 << USBS1); // two
// 8-bit
UCSR1B &= ~(1 << UCSZ12);
UCSR1C |= (1 << UCSZ11);
UCSR1C |= (1 << UCSZ10);
// flush receive buffer explicit
while(UCSR1A & (1<<RXC1)) UDR1;
// enable RX-interrupts at the end
UCSR1B |= (1 << RXCIE1);
// -- End of USART1 initialisation
// restore global interrupt flags
SREG = sreg;
return;
}
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
#define MIN_FRAMEGAP 68 // 7ms
#define MAX_BYTEGAP 3 // 310us
//############################################################################
// Is called by the uart interrupt
//############################################################################
void SbusParser(unsigned char udr)
{
static unsigned char ptr = 0;
if(!SpektrumTimer && udr == 0x0f) // wait for the start
{
ptr = 0;
}
else
{
if(++ptr == 24) // last byte
{
NewSBusData = 1;
}
else
if(ptr > 24) ptr = 25;
else
{
sBusBuffer[ptr] = udr; // collect all bytes
}
}
SpektrumTimer = 100; // 10ms gap
}
void ProcessSBus(void)
{
static unsigned char load = 0;
unsigned char bitmask8 = 1, sbyte = 2, i, index = 1, process;
unsigned int bitmask11 = 256;
signed int signal = 0,tmp;
if(!(sBusBuffer[23] & 4)) // This Bit contains the 'Signal loss'
{
TIMSK1 &= ~_BV(ICIE1); // disable PPM-Input
if(EE_Parameter.FailsafeChannel == 0 || PPM_in[EE_Parameter.FailsafeChannel] < 100) // forces Failsafe if the receiver doesn't have 'signal loss' on Failsafe
{
if(SenderOkay < 200) SenderOkay += 10; else SenderOkay = 200;
}
signal = sBusBuffer[1];
if(!load--) { process = (12*11 - 8); load = 2;} else process = (4*11 - 8); // lowers the processor load
for(i = 0; i < process; i++) // collect the single bits
{
if(sBusBuffer[sbyte] & bitmask8) signal |= bitmask11;
bitmask8 *= 2;
if(!bitmask8)
{
bitmask8 = 1;
sbyte++;
}
bitmask11 *= 2;
if(bitmask11 == 2048)
{
bitmask11 = 1;
signal = (signal-1024) / 5; // the resolution is higher than required
tmp = (3 * (PPM_in[index]) + signal) / 4;
if(tmp > signal+1) tmp--; else
if(tmp < signal-1) tmp++;
if(SenderOkay >= 195) PPM_diff[index] = ((tmp - PPM_in[index]) / 3) * 3;
else PPM_diff[index] = 0;
PPM_in[index] = tmp;
signal = 0;
index++; // next channel
}
}
NewPpmData = 0; // Null bedeutet: Neue Daten
}
NewSBusData = 0;
}
#endif