Date: Thu, 14 Sep 95 14:04:18 METDST From: marino.ladavac@aut.alcatel.at To: joachim@ee.uni-sb.de Cc: hackers@freebsd.org Subject: Re: EPP/ECP parallel port modes ? Message-ID: <9509141204.AA26273@atuhc16.aut.alcatel.at> In-Reply-To: <9509140802.AA14755@microdesk8.ee.uni-sb.de>; from "Joachim Koenig" at Sep 14, 95 10:02 am
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> Luigi Rizzo wrote: > >Does anyone know what are the various operating modes available on the > >newer parallel ports ? The controllers report the following: > > > > SPP EPP ECP > > > >I believe SPP is the standard mode, EPP might be the bidirectional mode > >(but don't know if the handshake lines change), and have no idea of > >what ECP stands for. > Typically, hardware implementations of EPP do the handshaking without > control and status port accesses, once enabled. One drawback is that > they keep the ISA bus occupied until the data has been received and > acknowledged by the reciever. To avoid bus hangups if the device does > not respond quickly enough, it generates an interrupt after a some > microseconds in this case. But if the device is fast enough, high > transmission speeds are possible. > ECP on the other hand uses FIFOs and DMA to speed things up even more, > with less overhead for a UNIX like operating system. The FIFO mode > can even be used for the SPP mode in forward direction. > The additional control/status/configuration ports of such a device > are at base+400+offset. This does not conflict with other devices > as only 10 bits are normally decoded for ISA ports, which masks out > the 1 in 400, giving the same addresses as base + offset which > correspond to the parallel port. > > There are currently only few peripherals, which support these enhanced > modes, but some hardware implementations of EPP & ECP are available for the > ISA bus: > SMC FDC37C665, SMC FDC37C666 from Standard Microsystems Corp. > A similar chip by National Semiconductor > an Intel Chip (sorry, no number). > So, what about a driver? > I've written an IEEE1284 device driver, which implements parallel port > fifo mode, nibble and byte reverse mode, but not yet EPP,ECP because of > lacking peripherals supporting these, but the hooks are there. > It's still alpha I think, but I would appreciate some testers, so write > me some email, if you are interested. One minor glitch: I've written it > for NetBSD, but the differences for FreeBSD should be small. > Joachim It definitely does interest me, especially as I have a dumb Laserjet clone hanging off parallel port. I could sure use faster bitmap transfer :) Any chance to get a hold of your driver? I'd like to try to patch it into 2.0.5R. /Alby > -- > email: joachim@ee.uni-sb.de University of Saarland, Germany, Europe > phone: +49 681 3023043 suffering should be creative, > fax: 2678 should give birth to something good and lovely > <Ende der Fahnenstange>
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