1.2 ROM Function Commands
Every 1-Wire device contains a globally unique 64-bit identifier number stored in ROM. This number can be used to facilitate addressing or identification of individual devices on the bus. The identifier consists of three parts: An 8-bit family code, a 48-bit serial number, and an 8-bit CRC computed from the first 56 bits. A small set of commands, called ROM function commands that operate on the 64-bit identifier is defined. The table below lists the six defined ROM commands.
| Command | Code | Usage |
|---|---|---|
| READ ROM | 33H | Identification |
| SKIP ROM | CCH | Skip addressing |
| MATCH ROM | 55H | Address specific device |
| SEARCH ROM | F0H | Obtain IDs of all devices on the bus |
| OVERDRIVE SKIP ROM | 3CH | Overdrive version of SKIP ROM |
| OVERDRIVE MATCH ROM | 69H | Overdrive version of MATCH ROM |