Re: [Discuss-gnuradio] GRC: Serial Port to Block Diagram Interface

[Josh Blum]

You should make a hier2 block that has a gr.message_source inside of it. 
You can put data you read from the serial port into a message queue. 
(internally) The message sink will pop items off of the queue and into a 
gnuradio stream.

Take a look in grc/grc_gnuradio/blks2/* for example. Several of the 
blocks in there make use of these message blocks and message queues. 
Then, to get the block in grc, you can make an xml file modeled off of 
one of the blocks in grc/blocks/*.xml

Hope that points your in the right direction.
-Josh

On 01/14/2010 02:17 PM, John Bonn wrote:
> Hello friends..
>
> I'm trying to setup some experiments to utilize the GRC environment. As a
> part of it, I'm reading samples off an ADC connected to a microcontroller
> connected to PC via UART/RS232 Serial, using PySerial module.
>
>   I have been trying to write a Source block for GR, where a listening thread
> would read the ADC samples from the Serial port into a global variable, and
> then, another thread wud "probably" pass the data into a gr.vector_source
> (like?) block within a hier2 block.
>
> Well, that was just the idea. But I guess the system doesn't work this way.
> I'm not sure whether I'm entering the message-blocks domain, which is
> expected to support such packetised(?) data. I read in the GRC Wiki - "add
> custom blocks" section that it might be possible to make such "special"
> functionality encapsulated in a block-diagram-safe block. Any suitable
> examples ?
>
> Conflicting again is the thought that ultimately samples from USRP and Audio
> sources are also probably caught in chunks and assembled into streams. But
> the sources for them look too complex and spread out for me to look into
> right now.
>
> I hope someone will make it clear for me and point me in a direction I can
> look for a quick hack.
>
> Cheers,
>
> John