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Altera_Forum
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14 years ago

Cascading CPLDs on different PCBs

I'm designing a basic harness continuity checker based on shift registers implemented in Max V CPLDs. I'm aiming for a modular/extendable PCB design for the project as it has several benefits (cost, ...
Altera_Forum's avatar
Altera_Forum
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14 years ago

Rather than using SPI to control the boards, you can also use an FTDI FT245 USB-to-FIFO component.

If your boards are all close together, then you would just have a USB cable to each board.

Each device would show up as a COM port. You can use the serial number in the FTDI chip to uniquely identify boards, which can in turn be used to create unique COM numbers or udev names under Linux.

You would still use a DIP switch in this case, as it allows the software to identify board 0, 1, 2, etc.

No microcontroller would be needed in this scheme.

I have an FTDI-to-Avalon-MM bridge that I've created ... I just haven't got around to documenting it yet ... you can use that code.

Cheers,

Dave