Please help choose an evaluation board

jusroc777 · ‎2016-11-29

Posted on November 29, 2016 at 20:25

Hello, I am new to embedded electronics MCU's.

However, I am hoping to start working on a prototype for a tactile physical control surface that incorporates a number of simple analogue controls (see below) that is plugged into a MCU which is then connected to a PC or MAC (via USB or MIDI interface) so that it can be used to control a host software application (most likely DAW).

Now, i think that the analogue components aren't going to be too complex in nature although I do plan to connect quiet a few.

So I would be really grateful for any advice regards to what prototyping board to use.

I ideally want to use a board with an ARM ST32 on, as I plan to program in either C or Assembly but also because i have a few books that explain how the architecture works and how to program boards using this MCU.

At the moment, my first proposed design will require a total of about 80 outputs

and a total of about 60 inputs. But that's without any clever electronic devices to minimize things.

The analogue components that i plan to incorporate are as follows:

endless rotary encoders

faders

latch buttons

loads of led's

an LCD display

LED rings for some of the rotary encoders (visual reference of settings).

Would be grateful for any advice regarding to what prototype boards i could use,

and perhaps even any software environment to use to program the board.

Please just bear in mind, I am running to a tight DIY / inventors budget, so don't have the same amount of money that perhaps a big company has to spend on developing a product.

Would still really appreciate any advice.

Thanks

Kind regards

#mcu-arm-cortex-m3-prototype

Tesla DeLorean · ‎2016-11-29

Posted on November 30, 2016 at 03:27

Your high pin counts tend to rule out a lot of the EVAL and DISCO boards, which already have heavily utilized pins (Memory, Display, etc).

You want more of a break-out board, you should perhaps look at a NUCLEO-144

If you are wedded to the Cortex-M3 there is the F205, but realistically the M4 for is perhaps a better choice, being faster and having the single precision FPU

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AvaTar · ‎2016-11-29

Posted on November 30, 2016 at 08:09

I would consider attaching the digital in/outputs (or most of them), not directly, but via a serial expander. Something like the PCF8574 (I2C) or even simpler like the 74164, 74165, 74166 come to my mind. Perhaps there are SPI options as well.

Assuming most of those IOs have low throughput requirements, this would reduce the MCU pin count requirements considerably (perhaps also the price).

jusroc777 · ‎2016-11-30

Posted on December 01, 2016 at 00:39

Hi Clive1, thanks for the info.

I think you are right. I have just taken a short look through the different boards.

I can't say i am an expert or understand everything involved, but the Nucleo 144 boards do look like the best for my purposes and the best value.

I also see that they have loads in terms of expansion options.

So probably will go down this route.

Thanks again for your help.

Kind regards