Re: [Discuss-gnuradio] Run time FIFO error

[Tim Newman]

Yes, bringing this back up. Back to the original topic.  When I get this FIFO ctrl error, the host is sending back an icmp port unreachable msg to the usrp, I grab this using wireshark.  

All I'm doing is running "uhd_usrp_probe".  I've tried with and without adding the --args addr=<ip> parameter, same thing using both.

I've debugged a bit, and increased the ACK_TIMEOUT in usrp/usrp2/usrp2_fifo_ctrl.cpp from 0.5 to 10.0 and it literally just sits at:

Creating the usrp device with: ...
-- Opening a USRP2/N-Series device...
-- Current recv frame size: 1472 bytes
-- Current send frame size: 1472 bytes

<sits here for 10 seconds>

Then spits out 

RuntimeError: RuntimeError: fifo ctrl timed out looking for acks

Again, there is a switch in between the USRP and the host.

Tim

On Thu, Jun 13, 2013 at 12:27 AM, Sean Nowlan <address@hidden> wrote:

I think 512 is the max value for N on N200/N210 hence 195kSps is minimum sample rate.

Karan Talasila <address@hidden> wrote:

@sean can you please tell me how you got minimum sampling rate for usrp N210 as 100*e6/512. I know that the sampling rate should be 100*e6/N where N is an integer. So N can be any integer even greater than 512 right. In that way, what is the minimum that the USRP accepts. what is maximum N that can be used.

On Thu, Jun 13, 2013 at 6:20 AM, Sean Nowlan <address@hidden> wrote:

On 06/12/2013 08:49 PM, Marcus D. Leech wrote:

On 06/12/2013 08:29 PM, Sean Nowlan wrote:

The minimum "reasonable" sample rate I've used is 2e5 (100e6/2e5 = 500). I think 100e6/512 = 195312.5 is the smallest supported rate.

Yup, sorry, you're right.  I tend to pick values that are valid for both 64Msps and 100Msps master clock rates, since I write apps that need to be reasonably
  agnostic with respect to hardware.

Ah, makes sense.

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--
Regards
Karan Talasila

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