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Message
From: Rudolf Usselmann <rudi@a...>
Date: Wed, 22 Oct 2003 17:26:20 +0700
Subject: Re: [usb] about the syn packet
On Wed, 2003-10-22 at 16:35, tomko81@h... wrote:
> Hi everyone,
> While i am reading the code usb_tx_phy.v in the PHY1.1 core, i
> find that everytime when the controller want to send packet to the
> host. It active the ld_sop_d signal and then write all zero to
> hold_reg
> then it will send out all zero before sending the real data.
> I would like to know why write "00000000" rather than
> writing "00000001" to the hold_reg, as the synchronized packet in usb
> should be "00000001".
>
> Thx for your help
actually it is 0x80 ... I'm not quite sure what/where you
are reading but my copy says:
// Out Data Hold Register
always @(posedge clk)
if(ld_sop_d) hold_reg <= 8'h80;
else
if(ld_data) hold_reg <= DataOut_i;
Remember LSB is transmitted first ...
rudi
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