A simple IR Tx Rx system - Packet Errors

hello.

i have tried make own little ir transmitter attiny85 16mhz external crystal.
i using nano tsop rx.

i have various tsop packages...i lost may what. have following ones available (labels on of package):225 ,386,233,148,322 , have 41 in breadboard.

they have green band (i assume 38khz) except 233 has brown/orange band.

i using code here send bytes 0-255 in loop 10ms delay.

my code uses high low period denote "1" , low low denote "0".
this give rx "rest" not on saturate (as per data sheet).

tsop41

i have burst 600us long @ 38khz giving ~23 cycles per burst.
each burst followed @ least 600us low period.

the datasheet says:
"minimum burst length 6 cycles/burst"
"after each burst of length gap time required of 6 70 cycles ≥ 10 cycles"
"for bursts greater minimum gap time in data stream needed of 70 cycles > 1.2 x burst length"
"maximum number of continuous short bursts/second 2000"

i thought had satisfied above having @ least 23 cycle gap after every 23 cycles.

i.e.

when run code shown, works. noticed packets causing issues, not expected +1 on last value. started log them , collected ~50,000 bytes occurred ~900 errors.

i plotted frequency table , can see ones seem "wrong" not random , there seems sway toward ones had previous numbers lot of 1s had higher failure rate.


how can eliminate issue?

code tx:

code: [select]

int baud = 600;
byte packsize = 8;

void setup() {
  clkpr = 0     // clock pre-scale register = 0. clock division factor = 1
          ;

  ddrb = 0
         | (1 << pb1); //set pin pb1 output

  ocr1c = 12;    // counter max...clock cycles before pin toggled.
  pllcsr = 0;

}
void loop() {
  // send numbers 0 256.
  (byte = 0; < 16000; i++) {

    senddata(i);
    delay(10);
  }
}
void senddata(int x) {
  int compare_bits = 0b10000000;
  highbit(); // startbit.

  (byte = 0; < packsize; i++) {
    if (compare_bits & x) { // if last bit in x == 1...
      highbit();                   // send highbit.
    }
    else {
      lowbit();
    }
    compare_bits = compare_bits >> 1; //shift compare along next bit...
  }
}

void highbit() {
  //turn 38-40khz pin on, delay (baud) , turn off.
  // high bit 1 adn 0.


  tccr1 = 0
          | (1 << ctc1)
          | (1 << com1a0) //bits 5 , 4 of tccr1 (com1a0 , com1a1) indicate when comparator == counter
          | (0 << com1a1)  // when a0 1 , a1 0, pin toggled on compare.
          | (0 << cs13)
          | (1 << cs12)  // table 12-5. timer/counter1 prescale select. divides clock amount.
          | (0 << cs11)
          | (1 << cs10);
  delaymicroseconds(baud);
  tccr1 = 0;
  delaymicroseconds(baud);

}

void lowbit() {
  // low bit 00;
  delaymicroseconds(baud);
  delaymicroseconds(baud);
}



code rx:

code: [select]

int baud = 600;
int doublebaud = baud * 2;
unsigned int rxd = 0;
byte state;
byte packsize = 8;
long errors = 0;
int last_num = 0;
long total_bytes = 0;

void setup() {
  // put setup code here, run once:
  pinmode(8, input);
  serial.begin(115200);
}

void loop() {
  // put main code here, run repeatedly:
  if (!digitalread(8)) {                 // hit start bit...
    delaymicroseconds(1400);

    (int = packsize; > 0; i--) {
      state = !digitalread(8);
      serial.print(state);
      rxd = rxd << 1;
      rxd += state;
      delaymicroseconds(doublebaud);

    }
    if (rxd != last_num + 1 && rxd > 0) {
      errors++;
      serial.print(",e");
    }
    else {
      serial.print(",o");
    }
    last_num = rxd;
    total_bytes++;
    serial.print(",");
    serial.print(rxd);
    serial.print(",");
    serial.print(total_bytes);
    serial.print(",");
    serial.println(errors);
    rxd = 0;

  }
}

thank help!

oh , before forget, tsop has 0.1uf cap across vs , gnd , 100ohm resistor between supply voltage , tsop rx voltage supply pin.

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