void OWWriteByte(int data) { int loop; for (loop = 0; loop < 8; loop++) { OWWriteBit(data & 0x01); data >>= 1; } }
//----------------------------------------------------------------------------- // Write 1-Wire data byte // void OWWriteByte(int data) { int loop; // Loop to write each bit in the byte, LS-bit first for (loop = 0; loop < 8; loop++) { OWWriteBit(data & 0x01); // shift the data byte for the next bit data >>= 1; } }
//----------------------------------------------------------------------------- // Write a 1-Wire data byte and return the sampled result. // int OWTouchByte(int data) { int loop, result=0; for (loop = 0; loop < 8; loop++) { // shift the result to get it ready for the next bit result >>= 1; // If sending a '1' then read a bit else write a '0' if (data & 0x01) { if (OWReadBit()) result |= 0x80; } else OWWriteBit(0); // shift the data byte for the next bit data >>= 1; } return result; }
//-------------------------------------------------------------------------- //! Perform the 1-Wire Search Algorithm on the 1-Wire bus using the existing //! search state. //! @return TRUE : device found, ROM number in ROM_NO buffer //! FALSE : device not found, end of search // int OWSearch() { int id_bit_number; int last_zero, rom_byte_number, search_result; int id_bit, cmp_id_bit; uchar rom_byte_mask, search_direction; // initialize for search id_bit_number = 1; last_zero = 0; rom_byte_number = 0; rom_byte_mask = 1; search_result = 0; crc8 = 0; // if the last call was not the last one if (!LastDeviceFlag) { // 1-Wire reset if (!OWReset()) { // reset the search LastDiscrepancy = 0; LastDeviceFlag = FALSE; LastFamilyDiscrepancy = 0; return FALSE; } // issue the search command OWWriteByte(0xF0); // loop to do the search do { // read a bit and its complement id_bit = OWReadBit(); cmp_id_bit = OWReadBit(); // check for no devices on 1-wire if ((id_bit == 1) && (cmp_id_bit == 1)) break; else { // all devices coupled have 0 or 1 if (id_bit != cmp_id_bit) search_direction = id_bit; // bit write value for search else { // if this discrepancy if before the Last Discrepancy // on a previous next then pick the same as last time if (id_bit_number < LastDiscrepancy) search_direction = ((ROM_NO[rom_byte_number] & rom_byte_mask) > 0); else // if equal to last pick 1, if not then pick 0 if (id_bit_number == LastDiscrepancy) search_direction = 1; else search_direction = 0; // if 0 was picked then record its position in LastZero if (search_direction == 0) { last_zero = id_bit_number; // check for Last discrepancy in family if (last_zero < 9) LastFamilyDiscrepancy = last_zero; } } // set or clear the bit in the ROM byte rom_byte_number // with mask rom_byte_mask if (search_direction == 1) ROM_NO[rom_byte_number] |= rom_byte_mask; else ROM_NO[rom_byte_number] &= ~rom_byte_mask; // serial number search direction write bit OWWriteBit(search_direction); // increment the byte counter id_bit_number // and shift the mask rom_byte_mask id_bit_number++; rom_byte_mask <<= 1; // if the mask is 0 then go to new SerialNum byte rom_byte_number and reset mask if (rom_byte_mask == 0) { docrc8(ROM_NO[rom_byte_number]); // accumulate the CRC rom_byte_number++; rom_byte_mask = 1; } } } while(rom_byte_number < 8); // loop until through all ROM bytes 0-7 // if the search was successful then if (!((id_bit_number < 65) || (crc8 != 0))) { // search successful so set LastDiscrepancy,LastDeviceFlag,search_result LastDiscrepancy = last_zero; // check for last device if (LastDiscrepancy == 0) LastDeviceFlag = TRUE; search_result = TRUE; } } // if no device found then reset counters so next 'search' will be like a first if (!search_result || !ROM_NO[0]) { LastDiscrepancy = 0; LastDeviceFlag = FALSE; LastFamilyDiscrepancy = 0; search_result = FALSE; } return search_result; }