AVRFT234 a small 6-pin AVR-ISP programmer

AVRFT234 Top AVRFT234 Underside AVRFT234 Top Angle

I found many fairly big/bulky AVR-ISP programmers in the "middle" of cables (USB cable->programmer->cable->[adaptor->]6-pin connector) but I wanted something compact for occasional use I could carry around and only needed a standard micro USB cable so I made the AVRFT234 utilising the FTDI FT234X.

It can be used with recent versions of Avrdude (6.3) to program AVR IC and bootloaders for many AVR based Arduino and clone boards using the standard 6 pin SPI pinout header.

AVR-ISP pinout

Pin 1 (MISO) of the AVRFT234 is indicated on the PCB with a triangle (visible in the centre picture above).

To add support to Avrdude for the AVRFT234 add the following configuration snippit to your avrdude.conf file. Under Linux the system level configuration file is frequently located at /usr/local/etc/avrdude.conf if installed from source.

  id = "avrft234";
  desc = "AVRFT234 an FT234XD based programmer";
  type = "ftdi_syncbb";
  connection_type = usb;
  usbvid = 0x403;
  usbpid = 0x6015;
  reset = 3;
  sck = 0;
  mosi = 1;
  miso = 2;

When using the programmer you need to specify the options to set the programmer (-c) to use and bitclock (-B).

  • "-c avrft234" matches the "id" in the above programmer definition.
  • "-B 20000" Sets bitclock
avrdude -c avrft234 -B 20000 <your other options>

By default the AVRFT234 does not provide power to the circuit being programmed.

If you need power to be supplied you can use the solder jumper on the side of the board to select either 3.3v or 5v. Please note the 3.3v can supply a maximum of 50mA (the 5v supply connects directly to the USB VBUS so this will normally be able to supply a lot more).

When using the AVRFT234 please be aware this is not a high speed programmer, it is a compact programmer so depending on the size of your binary it may take over a minute to program the device.