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Re: TimeStamps with ischo. transfers

Subject: Re: TimeStamps with ischo. transfers
From: BlazeAudio Developer <email@hidden>
Date: Sat, 22 Oct 2005 10:28:45 +0530
Delivered-to: email@hidden
Delivered-to: email@hidden

Hi Niels,

Can you confirm two things for Send NuDCLs:

a. The update step happens before the buffer is transmitted on the wire.

b. If a is true, then, does it imply that the timestamps being copied are invalid/stale.

And if a. and b. are true, then what is the proper way of getting correct timestamps for sent packets?

Thanks.
Devendra.

At 02:18 AM 10/22/2005, Niels wrote:

Hi Philip -

The update step for transmit copies the DMA timestamp to your
timestamp buffer, and can copy user defined isoch headers to the
hardware DMA program. If you are not using time stamps and you are
not updating your headers manually for a running program, you do not
need the update step.

.niels

niels gabel

firewire cpu software
apple computer, inc.

On Oct 21, 2005, at 7:31 AM, Philip Lukidis wrote:

Actually, I just reread the doc, which says that an update is
automatically done for transmit DCL commands (send) when the DCL
program is started, so I should be OK, as an update has been called
once before each sendPacketStart.

I'll just further mention that I have two possible cases for send
(I have no timestamps):
a) I call update on the sends before the send callproc.
b) I call update on the sends after the send callproc.

Since I don't currently use timestamps for send, either case should
be fine, right?

thanks,

Philip Lukidis

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Follow-Ups:
- Re: TimeStamps with ischo. transfers
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References:
	>RE: TimeStamps with ischo. transfers (From: Philip Lukidis <email@hidden>)
	>Re: TimeStamps with ischo. transfers (From: Niels <email@hidden>)

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