Implementation of 1-Wire with added Alarm Search Functionality
Dependents: Max32630_One_Wire_Interface
Diff: Masters/OneWireMaster.cpp
- Revision:
- 77:529edb329ee0
- Parent:
- 76:84e6c4994e29
- Child:
- 78:0cbbac7f2016
--- a/Masters/OneWireMaster.cpp Sat May 14 14:27:56 2016 -0500 +++ b/Masters/OneWireMaster.cpp Mon May 16 10:36:30 2016 -0500 @@ -35,6 +35,17 @@ using OneWire::OneWireMaster; +enum OwRomCmd +{ + ReadRomCmd = 0x33, + MatchRomCmd = 0x55, + SearchRomCmd = 0xF0, + SkipRomCmd = 0xCC, + ResumeCmd = 0xA5, + OverdriveSkipRomCmd = 0x3C, + OverdriveMatchRomCmd = 0x69 +}; + OneWireMaster::CmdResult OneWireMaster::OWWriteBlock(const uint8_t *sendBuf, uint8_t sendLen) { CmdResult result; @@ -120,3 +131,329 @@ } return crc; } + +void OneWireMaster::SearchState::reset() +{ + last_discrepancy = 0; + last_device_flag = false; + last_family_discrepancy = 0; + romId.reset(); +} + +void OneWireMaster::SearchState::findFamily(uint8_t familyCode) +{ + reset(); + romId.setFamilyCode(familyCode); + last_discrepancy = 64; +} + +void OneWireMaster::SearchState::skipCurrentFamily() +{ + // set the Last discrepancy to last family discrepancy + last_discrepancy = last_family_discrepancy; + + // clear the last family discrpepancy + last_family_discrepancy = 0; + + // check for end of list + if (last_discrepancy == 0) + { + last_device_flag = true; + } +} + +OneWireMaster::CmdResult OneWireMaster::OWFirst(SearchState & searchState) +{ + // Reset and begin a new search + searchState.reset(); + return OWSearch(searchState); +} + +OneWireMaster::CmdResult OneWireMaster::OWNext(SearchState & searchState) +{ + // Continue the previous search + return OWSearch(searchState); +} + +OneWireMaster::CmdResult OneWireMaster::OWVerify(const RomId & romId) +{ + OneWireMaster::CmdResult result; + SearchState searchState; + + searchState.romId = romId; + + // set search to find the same device + searchState.last_discrepancy = 64; + searchState.last_device_flag = false; + + result = OWSearch(searchState); + if (result == OneWireMaster::Success) + { + // check if same device found + if (romId != searchState.romId) + { + result = OneWireMaster::OperationFailure; + } + } + + return result; +} + +OneWireMaster::CmdResult OneWireMaster::OWReadRom(RomId & romId) +{ + OneWireMaster::CmdResult result; + RomId readId; + + result = OWReset(); + if (result == OneWireMaster::Success) + { + result = OWWriteByte(ReadRomCmd); + } + + // read the ROM + if (result == OneWireMaster::Success) + { + result = OWReadBlock(readId, RomId::byteLen); + } + + // verify CRC8 + if (result == OneWireMaster::Success) + { + if (readId.crc8Valid()) + { + romId = readId; + } + else + { + result = OneWireMaster::OperationFailure; + } + } + + return result; +} + +OneWireMaster::CmdResult OneWireMaster::OWSkipRom() +{ + OneWireMaster::CmdResult result; + + result = OWReset(); + if (result == OneWireMaster::Success) + { + result = OWWriteByte(SkipRomCmd); + } + + return result; +} + +OneWireMaster::CmdResult OneWireMaster::OWMatchRom(const RomId & romId) +{ + OneWireMaster::CmdResult result; + + uint8_t buf[1 + RomId::byteLen]; + + // use MatchROM + result = OWReset(); + if (result == OneWireMaster::Success) + { + buf[0] = MatchRomCmd; + std::memcpy(&buf[1], romId, RomId::byteLen); + // send command and rom + result = OWWriteBlock(buf, 1 + RomId::byteLen); + } + + return result; +} + +OneWireMaster::CmdResult OneWireMaster::OWOverdriveSkipRom() +{ + OneWireMaster::CmdResult result = OWSetSpeed(OneWireMaster::StandardSpeed); + + if (result == OneWireMaster::Success) + { + result = OWReset(); + } + + if (result == OneWireMaster::Success) + { + result = OWWriteByte(OverdriveSkipRomCmd); + } + + if (result == OneWireMaster::Success) + { + result = OWSetSpeed(OneWireMaster::OverdriveSpeed); + } + + return result; +} + +OneWireMaster::CmdResult OneWireMaster::OWOverdriveMatchRom(const RomId & romId) +{ + OneWireMaster::CmdResult result; + + // use overdrive MatchROM + OWSetSpeed(OneWireMaster::StandardSpeed); + + result = OWReset(); + if (result == OneWireMaster::Success) + { + result = OWWriteByte(OverdriveMatchRomCmd); + if (result == OneWireMaster::Success) + { + OWSetSpeed(OneWireMaster::OverdriveSpeed); + // send ROM + result = OWWriteBlock(romId, RomId::byteLen); + } + } + return result; +} + +OneWireMaster::CmdResult OneWireMaster::OWResume() +{ + OneWireMaster::CmdResult result; + + result = OWReset(); + if (result == OneWireMaster::Success) + { + result = OWWriteByte(ResumeCmd); + } + + return result; +} + +OneWireMaster::CmdResult OneWireMaster::OWSearch(SearchState & searchState) +{ + uint8_t id_bit_number; + uint8_t last_zero, rom_byte_number; + uint8_t id_bit, cmp_id_bit; + uint8_t rom_byte_mask; + bool search_result; + uint8_t crc8 = 0; + OneWireMaster::SearchDirection search_direction; + + // initialize for search + id_bit_number = 1; + last_zero = 0; + rom_byte_number = 0; + rom_byte_mask = 1; + search_result = false; + + // if the last call was not the last one + if (!searchState.last_device_flag) + { + // 1-Wire reset + OneWireMaster::CmdResult result = OWReset(); + if (result != OneWireMaster::Success) + { + // reset the search + searchState.reset(); + return result; + } + + // issue the search command + OWWriteByte(SearchRomCmd); + + // loop to do the search + do + { + // if this discrepancy if before the Last Discrepancy + // on a previous next then pick the same as last time + if (id_bit_number < searchState.last_discrepancy) + { + if ((searchState.romId[rom_byte_number] & rom_byte_mask) > 0) + { + search_direction = OneWireMaster::WriteOne; + } + else + { + search_direction = OneWireMaster::WriteZero; + } + } + else + { + // if equal to last pick 1, if not then pick 0 + if (id_bit_number == searchState.last_discrepancy) + { + search_direction = OneWireMaster::WriteOne; + } + else + { + search_direction = OneWireMaster::WriteZero; + } + } + + // Peform a triple operation on the DS2465 which will perform 2 read bits and 1 write bit + result = OWTriplet(search_direction, id_bit, cmp_id_bit); + if (result != OneWireMaster::Success) + { + return result; + } + + // check for no devices on 1-wire + if (id_bit && cmp_id_bit) + { + break; + } + else + { + if (!id_bit && !cmp_id_bit && (search_direction == OneWireMaster::WriteZero)) + { + last_zero = id_bit_number; + + // check for Last discrepancy in family + if (last_zero < 9) + { + searchState.last_family_discrepancy = last_zero; + } + } + + // set or clear the bit in the ROM byte rom_byte_number + // with mask rom_byte_mask + if (search_direction == OneWireMaster::WriteOne) + { + searchState.romId[rom_byte_number] |= rom_byte_mask; + } + else + { + searchState.romId[rom_byte_number] &= (uint8_t)~rom_byte_mask; + } + + // 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) + { + crc8 = RomId::calculateCrc8(crc8, searchState.romId[rom_byte_number]); // accumulate the CRC + rom_byte_number++; + rom_byte_mask = 1; + } + } + } while (rom_byte_number < RomId::byteLen); // loop until through all ROM bytes 0-7 + + // if the search was successful then + if (!((id_bit_number <= (RomId::byteLen * 8)) || (crc8 != 0))) + { + // search successful so set m_last_discrepancy,m_last_device_flag,search_result + searchState.last_discrepancy = last_zero; + + // check for last device + if (searchState.last_discrepancy == 0) + { + searchState.last_device_flag = true; + } + + search_result = true; + } + } + + // if no device found then reset counters so next 'search' will be like a first + if (!search_result || (searchState.romId.familyCode() == 0)) + { + searchState.reset(); + search_result = false; + } + + return (search_result ? OneWireMaster::Success : OneWireMaster::OperationFailure); +}