As far as performance goes, there are two things you have to consider: 1) The SL811HS is a bit-banger. The driver receives an USB transfer Done interrupt on each USB transaction. In each USB Frame, there can be multiple USB transactions. I remember that in a USB mass storage device, there can be up to 10 USB transactions in a frame. This means that the driver can received 10 USB Done interrupt in 1 millisecond time frame.
2) In addition to the USB done interrupt, the driver receives 1MS interrupt. This 1MS interrupt can not be slow down because it is used to indicated the start of the frame, keep track of the current frame number and schedule the USB frame. (The USB frame consist of isochronous, interrupt, control, and bulk transactions, in that order) If the 1MS is slowed down, the isochronous or interrupt transactions may not schedule correctly. Hopefully this answers your question.. Pei -----Original Message----- From: Thomas Chen <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] <[EMAIL PROTECTED]> Date: Tuesday, January 14, 2003 9:05 PM Subject: [linux-usb-devel] is 1 ms SOF interrupt ABSOLUTELY necessary??? >i am working on an embeded system using SL811 > >the 1MS interrupt is just eating up all the cpu cycle >(by the way, can any one provide some input on MINIMUM cpu horse >power needed to operate USB???) > >the question is whether it is possible to slow down this >interrupt, say to 5 MS instead of 1 MS??? > >dont know much about the other part of the drivers... would it >hurt? > >thanks a lot > > > > >------------------------------------------------------- >This SF.NET email is sponsored by: Take your first step towards giving >your online business a competitive advantage. Test-drive a Thawte SSL >certificate - our easy online guide will show you how. Click here to get >started: http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0027en >_______________________________________________ >[EMAIL PROTECTED] >To unsubscribe, use the last form field at: >https://lists.sourceforge.net/lists/listinfo/linux-usb-devel ------------------------------------------------------- This SF.NET email is sponsored by: Take your first step towards giving your online business a competitive advantage. Test-drive a Thawte SSL certificate - our easy online guide will show you how. Click here to get started: http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0027en _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
