15$ ECP5 board kit

ECP5 is a great FPGA, it was reversed in Trellis, it’s bigger than ICE40 that was reversed before in icestorm project. And it have lots of cool stuff like

  • multipliers
  • serdes
  • 25klut min (85 max)
  • and lots of memory bits

But ECP5 board available on the web are little bit expensive (if you have nothing to do with it ;). Even the OrangeCrab will be about 80$ minimum (but with DDR3 and USB on it).

There is a rumor on the web that this leds display board include an ECP5 :

The Board as received

It’s really interesting, because this board cost only $15 ! With the dual SDRAM (M12L16161A) provided and its dual gigabit ethernet phy (Boardcom B50612D B1KMLG). For this low-cost price I order one of course.

Removing the sticker unveil an ECP5 25k !

I just received it and if we remove the sticker we see a Lattice ECP5 ( LFE5U-25F-6BG256C).

\o/ It’s a really lowcost ECP5 dev kit !

But without schematics. Mike Walter began to reverse it and document the board on its github project.

[Edit 1 March]

Anton Blanchard give the jtag+uart pinout on its twitter profile :

Jtag Uart pinout from Anton Blanchard (twitter)

I configured the FPGA with this adapter from seeedstudio (7.6$), which is a simple FT2232 adapter.

Connect and configure with openFPGALoader

ECP5 is available in openFPGALoader list as we can see :

$ openFPGALoader --list-fpga
IDCode      manufacturer  family         model               
0x81113043  lattice       ECP5-5G        LFE5UM5G-85F-8BG381 
0x100381b   Gowin         GW1N           GW1N-4              
0x20f30dd   altera        cyclone 10 LP  10CL025             
0x3620093   xilinx        spartan7       xc7s15ftgb196-1     
0x362d093   xilinx        artix a7 35t   xc7a35              
0x900281b   Gowin         GW1N           GW1N-1              
0x1100581b  Gowin         GW1N           GW1NR-9             
0x13631093  xilinx        artix a7 100t  xc7a100             
0x41111043  lattice       ECP5           LFE5U-25F-6BG256C   
0x612bd043  lattice       MachXO3LF      LCMX03LF-6900C   
$ openFPGALoader -cdigilent --detect
idcode 0x41111043
manufacturer lattice
model  LFE5U-25F-6BG256C
family ECP5

Open source synthesize and place&route tools

We can then load a simple blinker bitstream with openFPGALoader. But first, we have to synthesize one. Trabucayre gave me a simple blinker project I added to the BLP (Blinking Led Project).

This project require yosys, nextpnr and trellis to be installed. Installations instructions are given on trellis repository.

$ git clone --recursive https://github.com/SymbiFlow/prjtrellis
$ cd prjtrellis
$ cd libtrellis%
$ make
$ sudo make install

Then for next-pnr:

$ git clone https://github.com/YosysHQ/nextpnr.git
$ cd nextpnr
$ cmake -DARCH=ecp5 -DTRELLIS_INSTALL_PREFIX=/usr/ .

And finally Yosys

$ git clone https://github.com/YosysHQ/yosys
$ cd yosys
$ make
$ sudo make install

Synthesize blinker

The blinker projet can be found on this github repository :

$ git clone https://github.com/Martoni/blp.git
$ cd blp/platforms/colorlight/
$ make
ecppack --svf blink.svf blink_out.config blink.bit

Then, once JTAG is plugged we can download it with openFPGALoader :

$  openFPGALoader -cdigilent blink.bit 
Open file blink.bit DONE
Parse file DONE
Enable configuration: DONE
SRAM erase: DONE
Loading: [==================================================] 100.000000%
Disable configuration: DONE

And see the orange LED blinking !

Some links

[this article will be edited as I progress]

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