Programmer - USB to serial UART

£12.28 (Inc. VAT)
£10.23 (Ex. VAT)
10.00 Grams
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USB to UART programmer for uploading Arduino software sketches and reading serial data from from all OpenEnergyMonitor hardware units: emonPi, emonTx, emonTH etc. 


For operating instructions and driver installations for Linux, Mac and Windows operating systems, follow this link:


Micro-USB cable is required, sold separately.


Soldering required (see the 'Assembly Guide' below). A pre-assembled unit is available for a small fee - just select the relevant check-box when ordering.



  • Low supply current :10mA 
  • Supported baud rates: 300 bps to 3 Mbps 
  • Power output to external logic 5V/3V3 (set by a removable jumper)



  • 1 X USB- serial UART dongle 


Does not include

  • Micro USB Cable


Assembly Guide 

All the information needed to assemble the programmer is on the FTDI data sheet:

The 6-pin right-angle connector in position CN11 is the correct one for the emonTx & emonTH. You should fit the connector so that it is on the same side as the USB socket.
Be sure to select the correct voltage with CN14: 3.3 V. (this is the default.)

See Figure 2 on the data sheet for the pin identification on the FTDI module - GND is at the opposite corner to the voltage selector.
The GND pin on the emonTx is marked on the front panel - it is nearest to the RJ45 socket. Therefore, the LEDs will point upwards when the module is plugged into the emonTx.
The GND pin on the emonTH is nearest to the centre, and is marked on the PCB.


Driver Installation and Operating Guide



Data sheet: LC231X datasheet.