Bela Mini Pure Data Serial

azita

Hi, I am using the Pure Data patch in the image. I am trying to get serial data from a device using the USB host-port on the Bela Mini. I don't receive serial data (notice that this patch works if I connect my serial device directly to my computer, why it has the number 4 in the comport object. I have tried in the Bela IDE by switching the 4 with /dev/ttyACM0)

giuliomoro

I bet you are getting a couldn't create comport message when you start this patch on the board?

[comport] is not installed by default and anyhow you shouldn't be using it because it does bad stuff (it does hw I/O from the audio thread). I recommend you update your board to the latest dev branch (see here) and then use the example PureData/serial which looks like this as a starting point:

azita

Thank you so much for your response. I can't see an example in the PureData drop-down in Bela IDE, but I've built the same patch as the one you've attached.
This is my version details.

This is what is happening. No serial data is printed out:

giuliomoro

I can't see an example in the PureData drop-down in Bela IDE, but I build the same patch as you've attached.

That's why I am suggesting you upate the board to the dev branch first. Basically, it's the regular update procedure but using this zip archive https://github.com/BelaPlatform/Bela/archive/refs/heads/dev.zip

After that, the patch will actually work.

azita

Thank you. I think I misunderstood above but it's all well now!

azita

Hi again @giuliomoro, I have tried to make this patch work. When I used Comport I was able to capture the two bytes following 97 (ASCII a) by using the logic in the picture I attached in my first message in this thread. When I use the same logic in the Pure Data example framework I don't receive the values. I do receive the values when I print SerialIn as done in the example after the "route myserial" object, so the serial data is coming in with 97 as the first byte with two bytes following, 98 as the fourth byte with two bytes following. The serial data starts coming in after a few minutes and the print-outs are slow but they are there(: I was wondering if you could help me get to the bottom of this - if Bela is sensitive to other objects or architectural decisions I'm currently using.

giuliomoro

I am not sure what you are trying to do by sending 97 or 98 into [route] every half second ... what's the format of the data you are expecting?

azita

Hi @giuliomoro, thanks for getting back to me. I used these two messages in the comport patch to send two messages (97 and 98) which would trigger the two ASCII characters a and b, each followed by two bytes representing a 16-bit integer. It's a [ASCII][int16] data format structure. I am new to Pure Data and not having the comport object made me confused, so what I'm essentially trying to do is to receive the same output as I did when I used the comport object, now using the example framework with route. To give more context, when I used comport and would print from the comport 4 9600 as seen in the following picture, the bytes on the second picture would be the output:

giuliomoro

does it mean that when you send out a 97 or 98 that triggers a response made of a 97 or 98 followed by two data bytes?

To send data out, you should send them to [s bela_serialOut], e.g.:

[sel 1]
|      \
[97(    [98(
|      /
|    /
|  /
[myserial $1(
|
[s bela_serialOut]

azita

@giuliomoro genius. Thank you a lot for your help. Now it makes sense.

azita

@giuliomoro Do you know what to do to make them act as separate float values?

azita

Solved🙂 For anyone who may need this solution sometime!

giuliomoro

I think you need a more complex state machine: in your case if you receive a 98 as part of one of the two data bytes, that value won't be parsed properly. If the incoming data comes only in response to a request sent out, you could reset the state machine whenever you send to bela_serialOut.

giuliomoro

Here's an example (includes testing code that you should remove when running on Bela):

Editable patch:

main.pd

2kB

Preview: