#ifndef F_CPU
#define F_CPU 16000000UL
#endif

#include <avr/io.h>

static void uart_sbus_init(void){
  UBRR0 = (F_CPU/(8UL*100000UL))-1;      // 100000 бод, U2X
  UCSR0A=(1<<U2X0);
  UCSR0C=(1<<UCSZ01)|(1<<UCSZ00)|(1<<UPM01)|(1<<USBS0); // 8E2
  UCSR0B=(1<<RXEN0);
}
static uint8_t rx(void){ while(!(UCSR0A&(1<<RXC0))); return UDR0; }

void sbus_unpack(uint8_t *b, uint16_t ch[16]){
  ch[0]=((b[1]|b[2]<<8)&0x07FF);
  ch[1]=((b[2]>>3|b[3]<<5)&0x07FF);
  ch[2]=((b[3]>>6|b[4]<<2|b[5]<<10)&0x07FF);
  ch[3]=((b[5]>>1|b[6]<<7)&0x07FF);
  /* ... остальные каналы аналогично ... */
}
int main(void){
  uint8_t f[25]; uint16_t ch[16];
  uart_sbus_init();
  DDRB|=(1<<PB5);
  for(;;){
    if(rx()==0x0F){
      for(uint8_t i=1;i<25;i++) f[i]=rx();
      sbus_unpack(f, ch);
      if(ch[2]>1000) PORTB|=(1<<PB5); else PORTB&=~(1<<PB5);
    }
  }
}