Sipeed has launched a $72, open-spec “Sipeed TANG Hex” SBC that runs Linux on an FPGA-enabled Zynq-7020 with 1GB RAM, 256MB flash, 10/100 Ethernet, 4x USB 2.0 ports, and an early RPi-like 26-pin GPIO header.

Chinese vendor Sipeed, which recently launched a Sipeed MaixCube dev kit based on a Kendryte K210 RISC-V chip, has returned with a Raspberry Pi-like SBC that runs Linux on a Xilinx Zynq-7020. The Sipeed TANG Hex is also referred to as the “Lychee HEX ZYNQ7020 FPGA Development Board Raspberry Pie Edition ZEDBOARD” on AliExpress, where it is selling for $72.47, and the “Taidacent HEX ZYNQ 7020 FPGA Development Board Raspberry Pi Edition ZEDBOARD XILINX FPGA Kit” on Amazon for $124.13.

Sipeed TANG Hex, front and back
(click images to enlarge)

Other names for the board include the Lychee Sugar and the Litchi candy. The latter, however, is also the name of a compute module based on an Anlogic EG4S20.

The Raspberry Pi reference alludes to the TANG Hex SBC’s RPi-like dimensions and general layout, and perhaps also to its 26-pin GPIO, which may or may not support early Pi add-on boards. The ZedBoard mention refers to the original Zynq-7020 SBC: Avnet’s community backed ZedBoard, which otherwise has little in common with the TANG Hex.

Z-turn

The $72 price seems reasonable considering that the cheapest — and only other open-spec — Zynq-7000 SBCs we know of are MYIR’s somewhat equivalent Z-turn Board, which sells for $119 with a Zynq-7020, 1GB RAM, and 512MB NAND flash, and less feature-rich Z-turn Lite, which sells for $75 with a Zynq-7010 with a lower-end FPGA and 512MB RAM. The Zynq-7020 has 2x 667MHz Cortex-A9 cores, which are linked tightly to an Artix 7 FPGA with 85K logic cells.

The headless TANG Hex ships with 1GB LPDDR3, 256MB NAND, and a microSD slot. There is a 10/100Mbps Ethernet port (compared to GbE on the Z-turn), and 4x USB 2.0 ports. Onboard interfaces include UART, JTAG, and the 26-pin GPIO. The board is powered from a 12V/3.5A DC jack, and there is a power button and 2x user LEDs.

The CNXSoft story that alerted us to the TANG Hex quotes from the sole review on Amazon, which suggests this may be one of those “you get what you pay for” boards. The SBC seemed to work fine, but there was no power supply or cables and the only documentation was a link to schematics.

There are indeed schematics, but apparently no Linux image, and the documentation was scattered. CNXSoft says Sipeed did not return its phone calls. So this may also be one of those boards that is technically open source, but offers less free tech support than many commercial boards.

Sipeed TANG Hex (left) and ALINX 7020 (ALINX XILINX FPGA)
(click images to enlarge)

The Amazon review praised an older and much more expensive Zynq-7020 board called the Alinx 7020, which offers full documentation and standard accessories. Unlike the TANG Hex, the ALINX 7020 board has a partner page on Xilinx. It sells for $269 on AliExpress as the ALINX XILINX FPGA.

 
Further information

The Sipeed TANG Hex — feel free to insert whatever alternative name you may prefer — is available at AliExpress for $72.47 plus $1.05 shipping to the U.S. and in China at Taobao for 439 RMB ($62) plus shipping and at Amazon for $124.13 with free shipping where it’s said to be from a company or reseller called Taidacent. More information may be found on Sipeed’s wiki. We did not see it on the Sipeed website.