Re: [Discuss-gnuradio] Dynamically changing parameters of a block

[kaleem ahmad]

Hi Eric and others,

I also have a similar problem, but it is not limited to 'gain control',
Actually I want to implement an echo back or ping pong transmission system.

First I implemented two separate transmitt and receive flow graphs in two
separate transmit(), and receive() functions as mentioned in the following:

Master Transceiver:

      Transmit()            Transmitt one data packet
      Receive()             Wait in receive for the echoed back packet or
timeout

Slave Transceiver:

      if (Receive()):             Always wait in receive
             Transmit()            Transmitt back the received data packet

But in this method I get an error 'cant open usb device....cant open USRP
0/1'

Then I found flowgraph.disconnect() method and thought that I should
implement a single flowgraph which can dynamically connect different blocks
to transmit and then disconnect and connect with receive blocks and so on...

Is it possible and is there any example code which doing something like this
or otherwise can you please suggest me some way to do this.

Thanks

Kaleem Ahmad



Eric Blossom wrote:
> 
> On Fri, Sep 26, 2008 at 06:40:29PM -0700, Karthik Vijayraghavan wrote:
>> Suppose I have myblock = gr.multiply_const_ff(var_value) sitting
>> somewhere in my flowgraph. I want the user to be able to change the
>> value of var_value by using a slider. I know how to make a slider, but
>> I am not able to find information on how to dynamically change the
>> block at runtime. One option that I can think of is to
>> 
>> 1. Stop the flow graph
>> 2. Disconnect the block in question with any block it may be connected to
>> 3. Redefine the block with new parameters
>> 4. Reconnect the block
>> 5. Restart the flow graph
>> 
>> I tried the above method, but I did know how to redefine an existing
>> block. Do I have to somehow "destroy" or "clear" the existing block
>> before defining another block with the same name?
>> 
>> Karthik
> 
> 
> No need for all of that, just call 
> 
>   myblock.set_k(new_value)
> 
> while it's running.
> 
> Eric
> 
> 
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> 
> 

-- 
View this message in context: 
http://www.nabble.com/Dynamically-changing-parameters-of-a-block-tp19698798p19721002.html
Sent from the GnuRadio mailing list archive at Nabble.com.