ColorCNC Colorlight 5A-75E/5A-75B as FPGA controller board

Very nice development. I just ordered mine board of AliExpress for 20 Euros. Contributing to the Python code / firmware and the driver for LinuxCNC is no problem for me. However: can somebody recommend a JTAG programmer for this card?

Any openocd supported device should work OK. I just picked up a ft232h based one.

I use an USB-Blaster clone and openFPGALoader.

What would be great is:

To have the FPGA configured for all pins as outputs & a Linuxcnc comp to suit. This would aid in figuring out what pin goes to which buffer on the 5A-75E V7.1
Then I could clobber up a pyvcp panel, simialr to the Parallel Port tester to control the pins.

For your board are you seeing much difference from what was documented in github.com/q3k/chubby75/blob/master/5a-75e/hardware_V7.1.md ?

It has the mapping of HUB75 pin to J[XX] connectors on the board already.


On my board (5A-75E V8.0) i just loaded the pin_scan program which emits UART signal on every single port so you can go around with serial cable onto each FPGA pin and it will tell you the pin that is mapped. All of my v8 pins I've scanned have aligned with the 5A-75E V6 of the board documented but i haven't completed 100% yet. Of the 10 or so i tested, they were all the same.

The pin mappings are defined in the Litex source, so for the time being I'll assume they are good.
github.com/litex-hub/litex-boards/blob/d...light_5a_75e.py#L200

What I want to know is which is which buffer has which signal on it. The reason being is that I will have to replace some of the buffers to get inputs.
What I intend to do is mod this code github.com/enjoy-digital/colorlite and with a bit of python, gtk and a pin test probe clip work it all out.

you might be overcomplicating it if thats what you want (locate which buffer each pin belongs to). Im thinking about also replacing some of these at some point but may use parport for inputs and just use this board for outputs and step generation in immediate future.

What I would do is use digital multimeter on continuity test mode on a known pin say, pin 1 on connector J16, have one lead connected to this pin from the multi meter, then sweep remaining lead across the buffer near that connector on bottom side of board, should be pretty easy to locate which buffer has that pin.

One thing to note is that on the J connectors, only pins 1,2,3,5,6,7 are connected to the buffers. the rest of the pins on each connector are 'shared' with the same fpga pins, you can see this in the connector mapping in the file you linked above.