Lpc2000

Hi,

 

In a past project I had to transmit a stream of uncompressed video via USB2.


It was possible to transmit > 32MBytes per second using just one bulk
endpoint, bulk packets can be transmitted more often than isochronous. 

Using several enpoints won't speed up the speed of transfer as all of them
have use the same USB.

 

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From: lpc2000@yahoogroups.com [mailto:lpc2000@yahoogroups.com] On Behalf Of
Martin Maurer
Sent: Sunday, September 11, 2005 11:06 PM
To: lpc2000@yahoogroups.com
Subject: [lpc2000] LPC2148: What endpoint(s) (bulk or isochronous) to choose
for big amount of data ?

 

Hello,

excuse my questions which are more USB related than to LPC2148: I want to
transfer some data from LPC2148 to PC. My data is a big amount of data.
"Jitter" is no problem. In reverse direction (PC -> LPC2148) there is almost
no throughput required. There are various endpoints to choose from in
LPC2148. Which one should i choose for my application ?

Here are my current ideas:

I can't deal with lost packets, so i can't use isochronous packets. Is this
right ? 
Control and interrupt endpoints are slow, correct ?
But for big amount of data, it looks like the isochronous data packets are
better, because the chunk itself can be 1023 bytes instead of only 64 bytes.
Or are the small bulk packets transferred more often than the big iso
packet, so throughput is the same ?
Can i use multiple bulk endpoints (e.g. i use physical 5, 11, 17, 23, 29 and
31) at the same time to increase throughput or is sum of throughput the same
as using the endpoint sequential ? When i fire the different endpoints is
there a guaranteed order of incoming packets, e.g. when i fire endpoint 5
and then 11, then 5 and then 11, do i received the packet 1,2,3,4 in same
order ?

What throughput do i get at all, with and without using DMA ?

Regards and thanks for helping an USB newbie...

                       Martin




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