Forums > MaxMSP

Serial port transmits, but doesnt receive

March 17, 2013 | 6:01 pm

I can communicate to my serial port device using mttty or hyperterm, but maxplus serial object only transmits. The serial object reports available COM devices successfully, but getbaud, getdtr, and monitors never show that the serial object receives any data or status. I’ve used inspector to enable buffering down to 1 char, I’ve checked the DTR setting (works fine on mttty, hyperterm), and tried different baudrates to no avail.

Here’s the patch:

– Pasted Max Patch, click to expand. –

March 17, 2013 | 6:29 pm

did you send bangs to your serial object ?
try to connect a [metro] to your inlet of the [serial] object.


March 17, 2013 | 7:16 pm

As kugelschreiber implies, serial is a polled object. You need to bang it at a fairly quick rate to get it to report the data that has been gathered. The help patcher could be clearer about this.


March 17, 2013 | 8:33 pm

You are right–I didnt catch that. I assumed a serial port would output received data as it arrived and did not read the help carefully enough. Banging a polling interval (metro) seems kind of odd but it appears to work. I’ll have to increase the buffer size since I’m running the interface at 115200 (around 10K chars/sec) but metro appears limited to once per millisec. I might try some things like using uzi to increase this rate since the dumped files are big.

Thanks!
Bob


March 17, 2013 | 10:22 pm

uzi won’t help here, I don’t think. Increasing the buffer, and using a fast polling rate are probably your best bet.


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