TouchDRO Adapter Firmware Release Notes

Firmware Editions

TouchDRO adapters come in three hardware families, and each has its own edition of the firmware. A plain version number, such as 3.5, is the firmware for the TDA-400, TDA-410 and TDA-420. The K edition (3.5K) is for the TDK-40 kits, and the L edition (3.5L) is for the second-generation ("V2") adapters for glass and magnetic scales that have been upgraded with the TouchDRO V3 Firmware Upgrade. An upgraded V2 adapter reports its model as TDA-420L. K stands for "Kit" and L stands for "Legacy".

The editions differ mostly in the pin mapping, since the inputs are wired to different microcontroller pins on each board. The kit and legacy boards also have simpler hardware, so their editions include only the features that hardware supports. The table lists what each edition has.

Edition	Adapter models	Features
No letter (3.5)	TDA-400, TDA-410, TDA-420	Four scale inputs, two auxiliary ports for a touch probe, tachometer, or home switches, home-switch inputs, power-loss position recovery, and a separate status light
K (3.5K)	TDK-40, TDK-40T, TDK-40 Plus	Four scale inputs, and a tachometer input on the TDK-40T and TDK-40 Plus
L (3.5L)	TDA-420L (V2 adapters with the V3 firmware upgrade)	Four scale inputs, touch probe, tachometer, and home-switch inputs, and a single heartbeat light

Firmware 3.0 was built for the TDA-400, TDA-410 and TDA-420 only. The K edition started with 3.1, and the L edition with 3.3.

After an Update Installs

Starting with 3.2, the adapter verifies new firmware on the first start after an update. Once the update is installed, the adapter will restart, and the status light will blink rapidly for about 10 seconds while the check runs.

The adapter needs to stay powered for about 20 seconds after it restarts. If it loses power before the check finishes, it will go back to the previous firmware, and you can install the update again.

Firmware 3.5

Released in February 2026 as 3.5, 3.5K and 3.5L.

What's New

• The adapter can now read iGaging scales that use the 21-bit data format, in addition to the SPC (Mitutoyo-style) and BIN6 formats added in 3.2.
• You can use a digital scale on any of the four inputs, on every TDA adapter and TDK-40 kit.
• When the adapter switches into firmware-update mode, the status light turns on and then flickers while the update is coming in. You will see this starting with the first update after 3.5.
• The status light blinks three times quickly when the adapter powers up, so you can tell that the firmware has started. On the TDA-420L, which has a single light, the heartbeat light blinks instead.

Fixes

• The RPM reading should be steadier at high spindle speeds.

Your adapter settings carry over to 3.5. If you are upgrading from 3.0 or 3.1, check the Y axis direction after the update (see Firmware 3.2).

Firmware 3.3

Released in October 2024 as 3.3 and 3.3L, and in December 2024 as 3.3K.

• New L edition for the TDA-420L. It supports the touch probe, tachometer, and home-switch inputs on these boards. The TDA-420L has only one light, so its heartbeat light also shows firmware-update and probe activity.

Firmware 3.2

Released in May 2024 for the TDA-400, TDA-410 and TDA-420.

What's New

• The scale inputs can now read SPC (Mitutoyo-style) and BIN6 digital scales. Power-loss position recovery works with quadrature scales only.
• While the supply voltage is too low, the heartbeat light goes out and the status light pulses once per second.
• After a firmware update, the status light blinks rapidly for about 10 seconds while the adapter checks the new firmware.

Fixes

• The two Y input signal lines were assigned in the opposite order from the X, Z and W inputs. Version 3.2 corrects this, so after the update a Y scale may count in the opposite direction. If you reversed the Y axis in TouchDRO to work around it, set it back.
• If the firmware stops responding, the adapter now restarts itself.
• The probe is ready for the next touch sooner. It now re-arms about ¼ second after a touch instead of about 1 second.
• Fixed a false probe signal that could occur right after power-up, and a stability problem in home-switch handling.

Firmware 3.1

Released in April 2024 as 3.1 and 3.1K.

• New K edition for the TDK-40 kits, with four scale inputs, the tachometer input on kits that have one, and position output over USB.
• The adapter now calculates RPM more accurately and without overflowing at high speeds, and the reading drops to zero more reliably after the spindle stops.
• Fixed a memory leak that could make the adapter unstable after running for a long time.

Firmware 3.0

Released in February 2024 for the TDA-400, TDA-410 and TDA-420.

Version 3.0 was a complete rewrite of the adapter firmware. Before 3.0, the adapter only sent data to the tablet. Version 3.0 added two-way communication for tighter integration between the app and the hardware: TouchDRO can read the adapter's model and firmware version, change its settings, and update its firmware. From the "Adapter Details" dialog, you can:

• Set what each input is used for: a scale, a touch probe, or a tachometer.
• Start a reference mark search on an axis.

Version 3.0 also added:

• Power-loss position recovery. The adapter saves the axis positions while the machine is idle and restores them when the power comes back.
• Home switch inputs. An axis can be zeroed from a home switch, and the auxiliary ports can be used for home switches as well.
• Firmware updates over USB. If a new version fails to start, the adapter goes back to the previous one on its own.