Re: TimeStamps with ischo. transfers

Subject: Re: TimeStamps with ischo. transfers

Date: Thu, 20 Oct 2005 14:18:45 -0700

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Hi Devendra.

My first question is: for a Send transfer (NuDCL), if I have a group of packets/send DCLs, where I have added a timeStamp pointer only for the last packet, and also, added a callback, and an update list(with all the DCLs for this group) for this last packet, what will the timeStamp contain?

a. Will it contain the time(cycle) that the last packet (on which the timeStampPtr was adder) was sent on?

b. Or Will it contain the time that the first packet of the update list was sent on?

c. Or will it contain the time *after* the last packet was sent?

Second Question: Is the timestamping mechanism in NuDCL different from (legacy)DCL mechanism (using the take timestamp OpCode)?

The timestamps for NuDCLs are associated with the DCL they are attached to. (so a. applies) The timestamp contains the time (from OHCI) that the hardware processed your DCL.

In legacy DCL programs, time stamp DCLs are associated with the nearest previous start of transfer DCL.

When update runs, the timestamp stored by OHCI in the hardware DMA program is copied to your timestamp location.

FYI, legacy DCL programs are translated to NuDCL programs before being compiled for the hardware.

.niels

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References:

>listen DCL program woes (From: Philip Lukidis <email@hidden>)

>TimeStamps with ischo. transfers (From: BlazeAudio Developer <email@hidden>)