Home
TEMP08 Serial One Wire Interface
TEMP08 Software Vintages

Firmwarehistory

Every TEMP08 firmware release from 1.00 to 4.06

The TEMP08 firmware changed often over fifteen years. Commands appeared, disappeared and came back, sensor support was added and trimmed, and in late 2014 the board moved to a new microcontroller that needed its own code line. Knowing which version a board runs explains most differences between a unit on the bench and the manual beside it.

Two processors, two code lines
Release timeline
How the feature set evolved
Upgrading and RELAY05 compatibility

First published August 20, 2003 · Text rewritten 2026

Isometric illustration of a chip being programmed in an open socket, with other chips queued beside it (AI-generated image)

Two processors, two code lines

TEMP08 boards were built around two different re-programmable microcontrollers, and firmware for one does not run on the other. Units shipped before December 2014 use the KX8 processor and run the 1.xx and 2.xx releases. Units shipped from December 2014 onward use the JB16 processor and run the 4.xx releases. The 4.xx line was a structural rewrite for the new chip rather than a feature overhaul; the user interface stayed almost the same.

There was a second split inside the KX8 line. Version 2.24 is meant for boards fitted with a 93C86 EEPROM, while 2.22 is the release for boards with the smaller 93C66. Version 2.24 added support for the larger memory as part of a circuit board update. Loading the wrong image for the processor or the EEPROM is the main way to make a working board misbehave.

Finding out what a board runs

The VER command prints the installed version, and the TEMP08 command reference describes the command set for 2.24 and later. Be aware that VER itself was removed in 2.15 to save program space, so a board from that period may not answer it. In that case, the presence or absence of other commands in the table below narrows the version down.

Release timeline

Version	Date	Processor	Main changes
4.06	Oct 2018	JB16	Alternative EEPROM port to allow a different circuit board layout
4.05	Jan 2015	JB16	More efficient DS2408 reset at power-up
4.04	Nov 2014	JB16	Structural changes for the new JB16 processor; SER command removed; no major interface changes
2.24	Sep 2012	KX8, 93C86 EEPROM	EAD command and auxiliary analog input outputs removed for a board update; large EEPROM support
2.22	Dec 2011	KX8, 93C66 EEPROM	Fixed RLY sometimes ignoring input; clearer error messages; INP, TMP, NOR, TYP, INI and RST blocked during a poll
2.20	Jun 2010	KX8	Last DS2405/6 code removed; TYP for DS2408; ETE command; multiple 1WIO input modules; renamed option commands; new DS2450 voltage syntax; character timeout cut from one minute to 20 seconds
2.19	May 2010	KX8	DEL command brought back; TOG removed as DS2405 support ended
2.18	Apr 2009	KX8	Debug voltage output for humidity reading errors
2.17	Nov 2008	KX8	Humidity bug fixed
2.15	Jun 2008	KX8	DS2438 current sensor voltage display; comma dropped from DS2423 readings for HomeSeer; VER and DEL removed to save space
2.12	Nov 2007	KX8	DS2450 reading fix; CRC check added
2.11	May 2007	KX8	LED command added; RST resets both DS2423 counters
2.09	Apr 2007	KX8	Reworked temperature algorithms for sub-zero Celsius and Fahrenheit accuracy; DS2405/6 status fix; DEBug removed
2.07	Feb 2007	KX8	Spurious DS2405 on/off fix; counter A shown for DS2423 used as L counter
2.06	Dec 2006	KX8	Fix for readings at exactly zero Celsius
2.05	Dec 2006	KX8	Multiple DS2450 sensors on one bus; DS2405 input change display fix
2.04	Jul 2006	KX8	Fix for intermittent first-sensor presence detection
2.03	Jan 2006	KX8	Fix for false DS2405 off status
2.02	Sep 2005	KX8	RLY handles up to 20 1WIO units; real-time presence detection via DIS; hidden options become discrete commands
1.13	Nov 2004	KX8	Hidden option 4 for DS2408 input polling; the version for legacy RELAY05 setups
1.12	Sep 2004	KX8	Debounce on missing-sensor checks
1.11	Sep 2004	KX8	INP command; faster polling and conversion; DS2450 voltage-only option; default DS2423 type; OFB/ONB error check
1.10	Aug 2004	KX8	Final DS2408 functionality
1.09	Aug 2004	KX8	ONB and OFB for DS2406/7; DS2408 relay outputs alongside or instead of RELAY05
1.08	Aug 2004	KX8	Interim release with a debug setting
1.07	May 2004	KX8	Fix for a lockup with polling off and repeated TMP
1.06	May 2004	KX8	DS2438 usable as temperature-only sensor; shorter TYP prompt
1.05	Apr 2004	KX8	More humidity error checks; option to hide the per-minute time; ZZZ becomes a hard reset; time display fix
1.04	Feb 2004	KX8	All DS2423 and DS2438 sensors now shown, not only the first
1.03	Nov 2003	KX8	DS2408 recognized; DS2406 on/off fix; DS18S20 display fix; option for the secondary on-board ADC
1.02	Oct 2003	KX8	DS18S20 reading fix; steadier humidity readings; AAG TAI8555 support; on-chip voltage display
1.00	Aug 2003	KX8	Initial release

How the feature set evolved

2003 to 2004: finding its feet

The 1.0x releases were mostly about reliability. Early fixes dealt with DS18S20 readings, humidity error handling and a bug where only the first DS2423 or DS2438 of each kind was shown. Through 2004 the focus moved to outputs: DS2408 recognition arrived in 1.03, DS2408-based relay outputs in 1.09, and the INP command for the 1WIO input and output board in 1.11. Many settings still lived in numbered hidden options.

2005 to 2008: the 2.x rework

Version 2.02 turned the hidden options into discrete commands, added real-time presence detection and let RLY address up to 20 1WIO units. The 2.0x releases then worked through temperature edge cases, including readings at exactly zero and below zero Celsius, and allowed several DS2450 converters on one bus. By 2.15 program space was tight: VER and DEL were dropped, and the comma in DS2423 counter output was removed because it upset HomeSeer's serial routines.

2009 to 2012: trimming legacy devices

Support for the DS2405 switch chip ended with 2.19, which also brought DEL back. Version 2.20 removed the last DS2405 and DS2406 code, renamed several option commands and changed some syntax, which is why manuals written before and after 2.20 do not match. The final KX8 releases, 2.22 and 2.24, fixed the relay command, restricted commands during a poll and added large EEPROM support.

2014 to 2018: the JB16 era

The move to the JB16 processor brought 4.04, followed by a DS2408 power-up improvement in 4.05 and an EEPROM port change for a revised circuit board in 4.06.

Isometric illustration of a chip in a socket with a glowing translucent cube above it, suggesting stored settings (AI-generated image)

Upgrading and RELAY05 compatibility

Both processors were re-programmable, but the upgrade route differed. For KX8 boards shipped before December 2014, the company handled upgrades by having the unit returned for reprogramming. JB16 boards shipped from December 2014 could be updated in circuit, and the company published the S19 file of the current version for owners who preferred to program the chip themselves. With the company no longer trading since the end of 2023, any upgrade now depends on having that file and suitable in-circuit programming hardware.

One older release stayed relevant for years. Version 1.13, from November 2004, was the last to support the legacy RELAY05 relay board. Setups that still depended on a RELAY05 needed to stay on 1.13, while newer installations used DS2408-based relay boards such as the 1WIO, driven by the RLY command.

Matching firmware to features

Need DS2405, DS2406 or DS2407 switches? Only pre-2.20 firmware read them, and support narrowed from 2.19. The 1WSwitch was the dedicated interface for those chips.
Need the auxiliary analog input? Its EAD command was removed in 2.24.
Need more than one DS2450? That arrived in 2.05.
Using the LED command? It first appeared in 2.11.

Before reflashing

Record the current settings first. Run DIS and save the output, which lists every stored sensor with its serial number and type letter, followed by the poll interval, units and display options. With that record, the sensor list and settings can be rebuilt with INI, TYP and SET if the stored configuration does not carry over to the new release. Keep the old firmware file as well, so the board can be returned to a known state if the new release behaves differently with an existing HomeSeer script or logging program. Scripts that parse the output are the most likely thing to break, because several releases changed line formats, such as the comma removed from DS2423 readings in 2.15 and the new DS2450 voltage syntax in 2.20.

The general behavior of the board, whichever version it runs, is described on the TEMP08 overview page.

Questions and answers

What was the last TEMP08 firmware version?

Version 4.06, released in October 2018 for boards with the JB16 processor. It added an alternative EEPROM port so a revised circuit board layout could be used. For older boards with the KX8 processor, the final release was 2.24 from September 2012, intended for units fitted with a 93C86 EEPROM.

How can I tell whether a TEMP08 has a KX8 or JB16 processor?

The dividing line is the ship date: units shipped before December 2014 use the KX8 and run 1.xx or 2.xx firmware, while later units use the JB16 and run 4.xx. The VER command reports the installed version, which identifies the line, although some releases from 2.15 onward lacked the command.

Why does my TEMP08 not recognize a command from the manual?

The command set changed between releases. VER and DEL disappeared in 2.15, DEL returned in 2.19, EAD went in 2.24 and SER in 4.04, and 2.20 renamed several option commands. Check the firmware version first, then compare it with the release timeline to see which commands that version knows.

Which TEMP08 firmware works with the RELAY05?

Version 1.13 from November 2004 was the release that kept support for the legacy RELAY05 relay board. Later firmware moved relay control to DS2408-based boards such as the 1WIO, operated with the RLY command, which from 2.02 onward could address up to 20 units.

Can KX8 firmware be loaded onto a JB16 board?

No. The two processors needed separate code, which is why the 4.xx line exists. The 4.05 and 4.06 releases were marked for JB16-equipped units only, and 2.22 and 2.24 were marked for KX8 units with a specific EEPROM size. Loading the wrong image is a common cause of a board that stops working.