$6 C-SKY Linux Development Board Features GX6605S Media SoC with C-SKY ISA

We’ve got plenty of ultra low cost , media capable Linux boards in recent years, but most of those are based on Arm architecture. More recently RISC-V open source ISA has started to show up in various boards such as Sipeed M1, but none of those can play video, or at least don’t come with an hardware video decoder.

C-Sky Linux development board does change that somewhat. It’s sold for about $6 (39 RMB) on Taobao, and $17.36 shipped on Aliexpress, and features Nationalchip GX6605S processor for DVB-S2 HD set-top boxes using C-SKY architecture, independent from RISC-V, although C-SKY is also a member of the RISV-C foundation.

C-SKY Linux Development Board
Click to Enlarge

C-SKY Linux development board key features and specifications:

  • SoC – Nationalchip GX6605S C-SKY ISA V1 CK610M 32-bit processor @ 574 MHz with 64MB DDR2 RAM, built-in DVB-S2/S demodulator
  • Storage – 4MB SPI flash for bootloader and media player program
  • Video Output – HDMI output up to 1080p; framebuffer resolution (for UI): 1280×720
  • Video Playback – H.264 up to 1080p
  • USB – 2x USB2.0 host ports
  • Expansion – 5-pin header with 3x GPIOs, 3.3V, GND
  • Debugging
    • JTAG via XX32F103C8T6 USB-JTAG chip (micro USB port)
    • UART console via CH340g USB-UART chip (micro USB port)
  • Misc – 5 user buttons, reset button, 4x LEDs
  • Power Supply – 5V/1A via micro USB port (JTAG or UART)
C-SKY board H.264 1080p video
C-SKY board playing a 1080p h.264 video

There’s no network connectivity nor large storage on the board – everything runs from the 4MB SPI flash, but you can add Ethernet, WiFi, and/or storage via the USB ports.

Documentation – mostly in Chinese – is available on Github.io, and support provided via Github issues tracker. Their Linux 4.16 based firmware is build with buildroot + uClibc-NG, and you can run it in qemu if you don’t have the board. You’ll also find documentation about C-SKY architecture, and the architecture has also recently been submitted and approved to the mainline kernel.

If instead of getting a development board, you’ll like to try one of the low cost GX6605S based set-top boxes, there are plenty on Alilbaba. Aliexpress has none, but they do sell the chip instead.

Thanks to Zoobab for the tip.

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2 years ago

I have seen some set top boxes on Alibaba with 512MB RAM, so it is definitely possible to add more then 64MB RAM.

BTW the STM32 should be capable of also forwarding an UART over USB, and I wonder if it would be capable of doing a USB OTG network interface as well…

2 years ago

If they would have picked the STM32F105/107, this one has OTG and Ethernet:


STM32F103 – 72 MHz, up to 1 Mbyte of Flash with motor control, USB and CAN
STM32F105/107 – 72 MHz CPU with Ethernet MAC, CAN and USB 2.0 OTG

2 years ago

Just the F107 has the Ethernet and USB OTG.

2 years ago

Actually those 512MB are expressed in Mbits, to divided by 8 it is 64MB of RAM.

2 years ago

Would make a nice Micropython board.

2 years ago

Without any built-in connectivity (WiFi, BLE), I doubt that it will gain any traction in the maker community.

2 years ago

RPI zero does not have any Wifi nor BLE BTW.

2 years ago

Such a great news source. Thanks! I’ll donate

2 years ago

It’s not RISC-V, but rather C-Sky abiv1, which has nothing to do with RISC-V.

2 years ago

If you want to point out an error it should be “It’s not SOC, but rather SIP”.
hahaha…. thats what they say on their website.