Date: Fri, 28 Jun 2002 02:26:51 -0500 From: John Musielewicz <[EMAIL PROTECTED]> Subject: Re: [LIB] L50 & USB?
On Thu, 27 Jun 2002 22:50:24 -0700, you wrote: >Date: Fri, 28 Jun 2002 05:44:58 +0000 >From: "neil barnes" <[EMAIL PROTECTED]> >Subject: Re: [LIB] L50 & USB? > > >>Date: Thu, 27 Jun 2002 15:35:47 -0500 >>From: John Musielewicz <[EMAIL PROTECTED]> >>Subject: Re: [LIB] L50 & USB? >> >> >><snip> >> > >> >There main problem with USB cards seems to be that the maximum data rate >>is >> >too low on the sixteen bit systems. According to the PCMCIA-CS howto, the >> >maximum rate is only about 2-3Mb/s, irrespective of the hardware. >> >>Is that simply to keep to specs? Or would it cause tranmission >>problems? >> > >I think that's the maximum rate the processor can get data to the bus. >There's no DMA AFAIK, and it's a slow 16-bit bus. It doesn't cause errors on >even a 100M network card, it just can't use all the available network >bandwidth (though the data it gets is still noticably faster than with a >10M). > >I suspect the timing requirements for USB are not meetable. Are you saying the minimum data speeds are hardwired and it only sends and recieves at those speeds and the usb controller will stop and give you an error if its not transmitting fast enough? That would be a problem and make usb a really inflexible method of a data interface. If all a person wanted was a usb-like interface with the same pinout, so it can be used with any usb equipped laptop, and wanted to use it as something like a programming interface speeds become much less revelant. Plus since many micro controllers use 8 and 16 bits busses it couldn't be used with those. I guess serial will live on. > >_________________________________________________________________ >MSN Photos is the easiest way to share and print your photos: >http://photos.msn.com/support/worldwide.aspx > > > > >************************************************************** >http://libretto.basiclink.com - Libretto mailing list >http://www.silverace.com/libretto/ - Archives > > -------TO UNSUBSCRIBE------- >Reply to any of the list messages. The reply mail should be >addressed to: [EMAIL PROTECTED] - Then replace any text >on the message's subject line: cmd:unsubscribe > --------TO UNSUBSCRIBE DIGEST------ >Do above but with this on subject line: cmd:unsubscribe digest >************************************************************** > ************************************************************** http://libretto.basiclink.com - Libretto mailing list http://www.silverace.com/libretto/ - Archives -------TO UNSUBSCRIBE------- Reply to any of the list messages. The reply mail should be addressed to: [EMAIL PROTECTED] - Then replace any text on the message's subject line: cmd:unsubscribe --------TO UNSUBSCRIBE DIGEST------ Do above but with this on subject line: cmd:unsubscribe digest **************************************************************
