MultiTech mDot Programming

To program the MultiTech System mDot module currently requires a fairly expensive development board. The dev board also includes space for developing additional hardware using Arduino shields. For reprogramming a mDot built into other hardware or individually it is possible to do this using the ST-LINK/V2-1 debugger/programmer from a ST Micro Nucleo-F411RE which is currently available for less than £10 from your favourite retailers including Farnell or RS. The idea for this post came after seeing the Espotel LoRa Module uses this method to upload new firmware.

The first requirement is the correct ST Micro Nucleo board. This must be the F411RE version as it includes the ST-Link debugger/programmer specifically for this MCU. Other Nucleo boards will not work in the file drag/drop mode, only with the ST-Link application to upload firmware.


Modify the Nucleo

There are a number of connections under the Nucleo board that need to be removed in order to separate the Nucleo MCU from the ST-Link debugger/programmer. This will effectively mean you will be no longer able to re-program the firmware on the Nucleo board without restoring the links.

Underneath the Nucleo there are a number of solder links:
2016-01-09 14.51.19-1

The one labeled SB12 should be removed. This stops the ST-Link debugger triggering a reset on the Nucleo MCU.

2016-01-09 14.51.07-1

The alternative is to remove the ST-Link debugger from the Nucleo board itself. This would render the main Nucleo board redundant and waste. Some components can be salvaged using a hot-air rework station if required.

The two parts can be carefully snapped by hand.

2016-01-09 15.02.34-1

The ST-Link debugger/programmer ready for a cable to connect it to the mDot.

2016-01-09 15.02.08-1

Programming Cable


Programming Connector

A programming header can be added to a design based on the MultiTech mDot modules.