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Before Hamming code

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Mark Qvist 2014-04-13 15:44:59 +02:00
parent 3644a35b79
commit 13af4dcd2b
1 changed files with 11 additions and 12 deletions
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23
Modem/afsk.c
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@ -369,20 +369,9 @@ void afsk_adc_isr(Afsk *afsk, int8_t currentSample) {
afsk->actualBits <<= 1; afsk->actualBits <<= 1;
// We determine the actual bit value by reading // We determine the actual bit value by reading
// the last 5 sampled bits. If there is three or // the last 3 sampled bits. If there is three or
// more 1's, we will assume that the transmitter // more 1's, we will assume that the transmitter
// sent us a one, otherwise we assume a zero // sent us a one, otherwise we assume a zero
// uint8_t bits = afsk->sampledBits & 0x0f;
// uint8_t c = 0;
// c += bits & BV(1);
// c += bits & BV(2);
// c += bits & BV(3);
// c += bits & BV(4);
// c += bits & BV(5);
// if (c >= 3) afsk->actualBits |= 1;
//// Alternative using only three bits //////////
uint8_t bits = afsk->sampledBits & 0x07; uint8_t bits = afsk->sampledBits & 0x07;
if (bits == 0x07 || // 111 if (bits == 0x07 || // 111
bits == 0x06 || // 110 bits == 0x06 || // 110
@ -391,6 +380,16 @@ void afsk_adc_isr(Afsk *afsk, int8_t currentSample) {
) { ) {
afsk->actualBits |= 1; afsk->actualBits |= 1;
} }
//// Alternative using five bits ////////////////
// uint8_t bits = afsk->sampledBits & 0x0f;
// uint8_t c = 0;
// c += bits & BV(1);
// c += bits & BV(2);
// c += bits & BV(3);
// c += bits & BV(4);
// c += bits & BV(5);
// if (c >= 3) afsk->actualBits |= 1;
///////////////////////////////////////////////// /////////////////////////////////////////////////
// Now we can pass the actual bit to the HDLC parser. // Now we can pass the actual bit to the HDLC parser.