On Wed, 30 Nov 2005, Home wrote:
> Hello There, > I'm writing embedded code on a mass storage device and > I'm having a little trouble getting the right specification for > DATA0 / DATA1 packet marking. The USB 1.1 spec doesn't really cover > this and I can't find the part of the 2.6.5 source where this is covered. Tale a look at usb 2 spec. > My understanding is that after configuration the first packet from the PC > to the device's BULKOUT will be a DATA0 and then a DATA1 and then alternating > until any reset when DATA0 is used again. This alternation is carried on > without > regard to the different CBW / DATATRANSFERS / CSW transactions. > > My lack of understanding is whether the BULKIN endpoint uses the _SAME_ DATA0 > / DATA1 sequence > or a seperate sequence of it's own. All the diagrams in the specs do not show > this sort of activity. > > Do I need two variables (one per endpoint) to hold the PID or just one? > Each and every endpoint keeps track of its own data0/1 sequence. IN and OUT endpoints are different as endpoints are identified by both Number and Direction. You need a variable per endpoint. > i.e.OUT 0 IN 1 IN 0 OUT 1 IN 0 OUT 1 OUT 1 etc > or OUT 0 IN 0 IN 1 OUT 1 IN 1 OUT 1 OUT 0 etc Neither of these sequences seems correct to me :) Olav ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
