
The LINK™ Family Manual
Version 1.6 ©iButtonLink, LLC 2016
Page 8
Extended Mode Slaves
General
Extended mode slaves are slaves based on a microprocessor instead of a 1-Wire® part from
Maxim-Dallas. They exist on the same bus with Maxim-Dallas 1-Wire® parts but do NOT
participate in normal mode communications. When the host selects extended mode, the Maxim-
Dallas parts disappear from the bus and the extended mode slave appears.
Extended mode is not
available on the LinkOEM or the LinkHub.
Extended Mode vs. Normal Mode
Extended mode is a proprietary extension to the 1-Wire® protocol by iButtonLink. LINK
TM
devices use ASCII commands to select which kind of slave is active on the bus.
Entering extended mode takes advantage of the fact that family code 0x00 is invalid. If Maxim-
Dallas ever deploys a normal mode part for family code 0x00, that part can NEVER be mixed
with extended mode slaves.
Extended mode is very similar to normal mode with several important differences:
•
Extended mode slaves only respond to command sequences that begin with an extended
mode reset (<Reset120>).
•
Extended mode slaves do NOT emit a presence pulse. Instead, an extended mode slave
will return a Status byte after a <Reset120>; bit 0, which is the same as the presence bit
in normal mode.
When entering extended mode from normal mode, the LINK
TM
devices issue the command
sequence found below in Table 1 to exit normal mode. Table 2 shows the status byte definition
for extended mode.
Command
Description
<Reset480>
Normal mode reset
0x55
Match rom
0x00
Family code (not valid for Maxim-Dallas parts)
Table 1: Table of extended mode commands