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Cmod A7 with more I/O


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Hi @robfinch,

I can put in a request for such a module, though I don't know if it will ever be created (if it does get created, I hope it will have more than one ground pin).

In the interest of general customer feedback (that you or anybody else is welcome to answer), what is it about the Cmod that you like?

Some reasons I can think of:
- Small form factor
- Price
- Lots of general purpose IO pins that aren't tied to a Pmod/etc form factor (rather than having pins be pre-routed to Ethernet or flash or whatever)
- IO pins are male to make connectivity to other systems/peripherals easy
- Not a Zynq

Besides more IO pins (which maybe gets difficult in terms of layout for such a narrow board, but I'm not a hardware engineer so that might be completely wrong) what sort of hardware details would you want to see on the device? (Keeping in mind whatever you value about the Cmod in the first place, if relevant. Or make a wish list, whichever is fine).

Random things I can think of:
- DDR memory
- Impedance matched signal pairs
- External powering option that doesn't require (de)soldering a component
- USB 3.x communication with the host
- Chip with faster I/O?
- Dedicated processor (i.e. a Zynq)

And probably either the most relevant or second most relevant section with regards to Cmods (presuming that price and form factor are the main reasons people choose a Cmod over any other Digilent board), what do you not want to see on a Cmod / don't care if it's not there?

Ideas:
- DDR memory
- More than 2 buttons (one button is a reset)
- More than 4 LEDs (or more than 1 RGB LED)
- Random peripherals like LEDs, buttons, Pmod port, Ethernet, display adapters, etc
- High end chip with fast I/O
- A Zynq board (DDR memory would come with this as is the nature of Digilent made Zynq based boards)

Thanks,
JColvin

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You have got me thinking about what I am trying to do. I may be trying to put too much functionality into one CMod. I suppose I could use multiple CMods but that’s a pricey solution.

I like the fact that it can be treated like an IC and embedded into another project without having a huge board and cables. The small form factor appeals to me. It can be used as a prototype to the FPGA chip without having to develop a board. I suggested a 64-pin 0.9” wide dip as it still fits in a breadboard. But a 68 pin PLCC form factor would be okay too; might be harder to prototype with though.

The lots of undedicated I/O pins appeals to me.

I have designed a CModA7 into a single board computer where it is used for miscellaneous functions including address decoding for other devices, so lots of address inputs, serial I/O port, VGA port. Address and data bus, plus read/write and circuit select take 26 pins. There are only 44 digital I/O on a CModA7. I would like to be able to support two or more serial ports (with cts, rts) and more VGA output signals, but there just are not enough pins. Seems like I need jut a few more pins. I would like it also to control a clock generator. And SPI port as well. Random bitstream port. So, some more GPIO’s would be good. Even if there were only a handful more pins some sort of I/O muxing could be done.

Things I do not care about for the CMod:

More switches and LEDs and other random peripherals.

DDR memory.

 

I have been looking at a ZYNQ board as it has some appeal having the processor on board already.

 

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