Home > Hardware, Testing > How to Access the Serial Console in MK808 mini PC

How to Access the Serial Console in MK808 mini PC

Omegamoon has done a pretty neat hack on MK808 Rockchip RK3066 mini PC to connect a Sparkfun USB to TLL board and access the serial console for bootloader and kernel debugging. The first thing he had to do was to open the device, remove the heatsink, and locate the Rx/Tx pads on the board.

3 Wires connected to Ground (Blue), Rx (Green) and Tx (Yellow)

3 Wires Connected to Ground (Blue), Rx (Green) and Tx (Yellow)

The Rx and Tx pins are accessible through pads, not via through holes, so it’s just a little more difficult to solder, but nothing too challenging. He and his brother also soldered another cable to the ground. Then they inserted a 6-pin header via the ventilation holes of the device, soldered the 3 wires to the header, and fix the latter to the casing.

MK808 UART Pin Header

Finally, they just inserted the debug board in the pin header, connected the USB cable to their PC, and started minicom (or equivalent) to start accessing the serial console.

MK808 UART Debug Board

I think that looks awesome. You can find all the steps, and high resolution pictures on Omegamoon blog.

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Categories: Hardware, Testing Tags: hack, how-to, mini-pc, mk808
  1. onebir
    January 31st, 2013 at 20:16 | #1

    So this is like a way to SSH into a device without ethernet (or whatever)?

  2. January 31st, 2013 at 20:18 | #2

    @onebir
    That’s one way to look at it :). You can see all debug output from the time the board starts. You can stop the boot process, and change the bootloader (U-Boot) settings, and so on…

  3. Robert D. Martin
    January 31st, 2013 at 22:58 | #3

    The UG802 was not only able to connect wia ethernet and DSL with my ISP but also connected handily to a USB hub, which enabled me to access external HDDs. I was, therefore, quite pleased with it. In fact, had I been able to boot with it into Linux distributions of my choice as in the days before (U)EFI, Secureboot, TPM and Win8, then I might eventually have come to consider it to be as suited to my particular needs as a full-fledged PC.

    Unfortunately, however, the UG802 turned out to have one grievious weakness: its connectors, which all too easily during normal usage can break away from its motherboard.

    In my case, just as I went about disconnecting the mini-USB power supply cable from the UG802 in order to take it with me during a vacation, then that connector emerged from the case still attached to the cable, even bearing with it a piece of the motherboard.

    I therefore recommend to all who would nevertheless use a UG802 (presumably also any other similarly mini-format PC ) that some manner of care be taken to strengthen the motherboard’s connectors. Failing that, then it might be wise to once only connect the appropriate cables to them and somehow firmly glue or tape them so into place that no risk of damaging the motherboard remain. Maybe placing thereby the mini-format PC into a protective case would help in achieving that goal?

  1. April 26th, 2013 at 16:55 | #1
  2. July 10th, 2013 at 17:25 | #2