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[on:]

I am at the final stage of a prototype that needs 30 I/O pins in total. So far I have the project prototyped using a Mega 1280 but I am looking for a more permanent, less expensive option. Sort of like a pro mini board that has no USB circuitry, just a board that has a mega1280, crystal, FTDI connectors and solder pins for each I/O.

Not sure if something like this exists so I would check with everyone here.

Thanks,
Mike

[Reply #1 on:]

What are you using the pins for?

You may be better to use an Uno and shift register / LED driver chip.

Also if they are input switches, there are ways of combining these with resistors and just using one Analog input, or having a key matrix.

[Reply #2 on:]

The project is a 50 pin cable tester. Right now I have 7 74HC164 shift registers and 7 74HC151 multiplexers. One I/O is used fore the switch, 6 for the lcd and 20 to control the logic chips.

Is there anything in between the UNO and the Mega for digital I/O? Possibly a clone or something? It would be a shame to have to use a Mega 1280 for the project. One possibility is to grab a blank Mega 1280 board and just solder on the Mega and crystal.

[Reply #3 on:]

If all you need is more I/O then you should look into using an I/O expander such as the MCP23017 or MCP23S17.  Each one gives you 16 I/O pins.  If you want something already built up on a shield then look into the 'Centipede Shield'.

Don

[Reply #4 on:]

Sort of like a pro mini board that has no USB circuitry, just a board that has a mega1280, crystal, FTDI connectors and solder pins for each I/O.

If there is no USB circuitry, what do you need the "FTDI connectors" for? The FTDI chip is what provides the USB to serial capability.