RE: [ethmac] MAC Data Question

["Igor Mohor" <igorm@opencores.org>]

Hi,

 

since OpenRISC uses big endian organisation, that's how data is served:

 

At this moment if you have   data[31:0] = 32'h12345678

 

than nibbles would be transmit in this order: 1 2 3 4 5 6 7 8.

 

 

Some old version used to use small endian.

 

Regards,

    Igor

-----Original Message-----
From: owner-ethmac@opencores.org [mailto:owner-ethmac@opencores.org]On Behalf Of Illan Glasner
Sent: 5. april 2002 4:49
To: ethmac@opencores.org
Subject: RE: [ethmac] MAC Data Question

Hi,

 

   Hope I'm not confusing but basicly if you have a word which look like

 

data[31:0] = 32'h12345678

 

than you will send the nibble 7 8 5 6 3 4 1 2

 

the first nibble is also the first to be send only the byte for exmple 78 the first nibble is 7 .

 

notice that the way you read the number is "opposite" to the way they are send for example sdf which is

1010 1011 when you simple look on it than it look like A B but it is actully 5 D since the MSB is in the right side.

 

have a nice day

 

   Illan

-----Original Message-----
From: David Norvell [mailto:norvell@starband.net]
Sent: Thursday, April 04, 2002 4:34 PM
To: ethmac@opencores.org
Subject: RE: [ethmac] MAC Data Question

When I simulate the MAC and look at the Tx data coming out I see a 0 between the SFD and the first nibble of my data.  Is this correct?

 It looks like this, starting with the preamble:

5,5,5,5,5,5,5,5,5,5,5...D,0,0,A        ("0" is my first data nibble and "A" is my second nibble)

Is this correct?

 

Also should my data be transposed or not?  If my first byte is 0a, should the 0 come out first or the a?

 

Thanks for your help.

Dave