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List:       gnuradio-discuss
Subject:    Re: [Discuss-gnuradio] Padding for USRP
From:       Tom Rondeau <tom () trondeau ! com>
Date:       2013-02-27 15:10:13
Message-ID: CA+SzT6jYVWODo5tZbbqj9BVQdfdQ7nyLiu9YKgUW_Gb9VPkofw () mail ! gmail ! com
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On Tue, Feb 26, 2013 at 9:12 PM, Josh Blum <josh@ettus.com> wrote:
>
>
> On 02/26/2013 08:03 PM, Manu T S wrote:
>> In gnuradio/digital/packet_utils, the packets are padded to make it a
>> multiple of 512 bytes to be sent across the USB(As per the comment there).
>>
>> USRP2 and N210 uses ethernet connection. Is it important to have padding
>> for USRP in for these devices? If so is it the same number? ( 512 bytes to
>> be sent across ethernet )
>>
>
> You should not need any padding. All of the devices (except usrp1) send
> samples encapsulated in a packet format so the boundaries of the samples
> are known by the device.
>
> I dont think you need the padding for USRP1 either, since UHD will flush
> out the buffer to a 512 byte multiple if it sees the EOB specified.
>
> -josh

Yeah, that requirement comes from back in the libusrp days where it
was just a pipe that we provided samples to and had to make sure the
boundaries were met ourselves before sending along. With the UHD
interface, you can safely ignore it.

Tom


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