MachXO2280 board serial over JTAG

[Harvs]

Wondering if anyone has looked into this and found a way of doing it.

The XO and XO2 boards have a high speed FTDI device on them used for the JTAG programming.

Would be nice if after configuration this could be re-purposed as a generic serial port for communicating with the device.  There's no point if it requires breaking the programmer.

[abyrvalg]

Are you talking about this board http://www.latticesemi.com/en/Products/DevelopmentBoardsAndKits/MachXO2BreakoutBoard.aspx ?
There is a dual channel FTDI, but rumours says that only channel A is used for programming, so it should be possible to solder some wires to channel B and use it (SPI mode should be an easiest way).

[Harvs]

The board I've got is similar, but the older cousin:
http://www.latticesemi.com/en/Products/DevelopmentBoardsAndKits/MachXOBreakoutBoard.aspx

However I'll probably use the XO2 boards in the future.

I'll have to look more closely at the FTDI device on it.

[andersm]

Older thread on the subject.

[abyrvalg]

Your board has the same dual channel FT2232H. If the rumours are correct, FTDI pins 16-19 (channel A JTAG) should be connected to PLD's JTAG, while the rest FTDI IOs should be not connected. Channel B SPI is on pins 38-41. Check page 9 here http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT2232H.pdf

[Harvs]

So channel B definatly works.

Out of the box how the drivers are setup it's configured as a UART.  However there's some soldering pain to be had hooking up wires to the 0.5mm pitch.  But it does work fine.

I haven't looked into how you change it to SPI mode, I'm guessing it would need a different config file?

Why the hell they didn't just break these pins out to a header is beyond me.  Total fail...

[abyrvalg]

There is no need to configure FTDI for some specific mode before use. Just use correct MPSSE DLL and the chip will enter that mode. This http://www.ftdichip.com/Support/SoftwareExamples/MPSSE/FTCSPI.htm should work out of the box.
I wrote a simple SPI EEPROM programming tool based on these FTDI's examples some time ago - there were no problems.

[Harvs]

Ok great.  Thanks for your help, I'll give it a go.