Serial cable


This guide shows you how to create a serial cable.


Serial using gadget USB

It seems it is possible to get serial connectivity using the on-board USB port. Take a look at for more info.

How to create a serial cable

There are multiple ways of creating a serial cable. Chose one according to your knowledge, time constraints, etc..

  • Create a cable by soldering a simple circuit involving a MAX3223 level shifter. This will connect your 12V serial connector (RS-232) to the 3V serial connector of the GP2X.
  • Resolder an original Samsung E810 data cable which already contains a level shifter chip and follows the wiring instructions given here: SamsungE810Cable
  • Rewire a cheap non-original E810 USB data cable. This may involve no soldering, a multimeter is however strongly recommended. This lets you attach your GP2x serial console to an USB port which is more common and convenient than RS-232 these days. Follow these instructions: SamsungE810USBCable

Building the circuit


Schematic for a serial cable

The EXT connector

The serial cable uses the serial I/O functionality found on the EXT Port. You will need to get one of the available EXT Port connectors.


Part list

  • 1x MAX3232
  • 5x capacitator 100nF (C1-C5)
  • 1x SUB-D connector (9 pins, female)
  • 1x EXT connector

Part numbers for ordering

Part Numbers



Reichelt Elektronik (Germany)

Maplin (Uk)

Digikey (US)

1 MAX 3232 CPE 3,0 to 5,5V low power up to 1mbps true rs-232 MAX 3232 CPE DT26D MAX3232ECPE-ND
5 Capacitator 100nF TANTAL 0,1/35 WW54J 493-2336-1-ND
1 SUB-D connector (9 pins, female) D-SUB BU 09 RK61R
1 (optional) experimental board (for building the circuit) UP 932HP JP52G
1 (optional) IC socket (16 pins - for MAX3232) GS 16 BL19V


Powering up will echo both u-boot and the bootup process to the serial port of the gp2x. If you are not seeing anything on your PC, try another serial port or check the wiring of your serial cable.


Start HyperTerminal and create a new connection with the following settings:

  • 115200 bps
  • 8 bits
  • No parity
  • 1 stop bit
  • Hardware flow control: Xon/Xoff


  • run minicom
  • configure the comm parameters (CTRL-A, Z, P): 115200 8N1
  • hit enter to return to the serial terminal and boot the gp2x to watch what happens

Misc info

Here are some pages with details on the TTL->RS232 conversion required:

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