From theom+news@chiark.greenend.org.uk Thu Aug 1 12:43:14 2002 Path: ewrotcd!not-for-mail From: Theo Markettos Newsgroups: comp.sys.acorn.misc Subject: Re: etherlan201 and MAU....please help!!! Date: 01 Aug 2002 12:42:00 +0100 (BST) Organization: University of Cambridge, England Lines: 72 Sender: Theo Markettos Message-ID: <8Do*IEKup@news.chiark.greenend.org.uk> References: <3d486915.3318936@powernews.libero.it> <3d487640.6690625@powernews.libero.it> NNTP-Posting-Host: chiark.greenend.org.uk User-Agent: tin/1.5.10-20011117 ("Darkcell") (UNIX) (Linux/2.2.20 (i686)) Originator: theom@chiark.greenend.org.uk ([212.135.138.206]) Xref: news.chiark.greenend.org.uk comp.sys.acorn.misc:102152 Gabrio TheClue wrote: > > just received a mail from i-cubed. They told me that my network card > hasan't AUI standard connector. > > But that's fool! 15 pin Dsub is AUI! IT IS A NETWORK STANDARD! > If you would to make your custom standard USE CUSTOM CONNECTOR! > I paid a lot for the card, then on i-cubed site i saw that i needed > also a MAU, so i paid a lot for MAU (plus delivering from USA...i'm > from italy) and...nothing! They used a 15 pin Dsub that is not an AUI. > And of course their MAU is absolutely ultra expensive! OK, don't panic. There's not really a lot in a MAU, so if you've a bit of electronics experience, you can either make one yourself, or adapt your AUI. Please note that I haven't tried any of this, so there may be errors in the following information. The pinout of the 15 pin connector at the back of the network card, which I think gets translated 1:1 into the 15 pin D connector on the back of the computer is: SK16 A3020/A4000 Network socket Econet 10b2 10bT 1 Clock+ CD- nc 2 Clock- CD+ nc 3 gnd gnd gnd 4 Data- TX- nc 5 Data+ TX+ nc 6 nc nc RXI- 7 nc nc RXI+ 8 nc RX- nc 9 nc RX+ nc 10 nc VCC VCC 11 nc nc TXOD- 12 nc nc TXOD+ 13 nc nc TXO+ 14 nc IDC IDC 15 nc nc TXO- Ignore the Econet, I just typed that in for completeness. The 10base2 pinout is the one you want to look at if you're interfacing to AUI, the 10baseT if you want to build your own MAU. Now for the AUI. The pinout can be found in: http://www.cisco.com/univercd/cc/td/doc/product/lan/14201220/14_1220u/csspec.htm Note that this requires a 12V supply, which the Acorn doesn't provide, so you'll need an external PSU. Also, the etherlan uses (I think) the IDC line to sense which type of MAU is plugged in. You want to tell it a 10base2 MAU, even if you're connecting to 10baseT, since this will put the controller in AUI mode. By the looks of http://www.de.freebsd.org/cgi/cvsweb.cgi/syssrc/sys/arch/acorn26/podulebus/if_ehreg.h?rev=1.1.6.1&cvsroot=netbsd I think you want to connect this to 5V to indicate 10base2 (but experiment). If you wire up a cable to these specs, you will hopefully be able to get the AUI working. If you're feeling even braver, you could build your own MAU, which doesn't need a 12V supply. A couple of useful links are: The datasheet (I think) for the controller on the EtherLan200: http://www.national.com/pf/DP/DP83902A.html page 8 of the datasheet is particularly useful, since it shows how to link the pins on the MAU interface to connect to a 10baseT cable. In particular, all you need is a few resistors and capacitors and a pulse transformer. You should be able to get a suitable transformer off an old PC 10baseT card - they look like a large box on the PCB (don't use a 100baseTX card). My el-cheapo ISA NIC has an FC-22 transformer which would do the job - for an example circuit, see http://web51.hw-server.com/hw_web51.html In this case you'll (probably) want to wire the IDC line to ground to select the twisted pair output from the controller. Hope this helps, Theo ------------------------------------------------------------------- Stephen Leary emailed some corrections: Date: Mon, 1 Mar 2010 10:40:25 +0000 Subject: A3020/A4000 MAU From: Stephen Leary Theo, I was recently attempting to build a MAU for the A4000 for an etherlan 209 and thought i would share results. First thing to note is that there is not a 1:1 mapping between SKT16 and the DB15. Second is that the IDC pin is open collector so must be driven low to indicate a connected AUI. Finally here is a list of all the connections between the main IC and the socket. Note that the connects differ significantly from your information. SKT16 DB15 SIGNAL 1 1 CD- 2 9 CD+ 3 2 IDC (GND indicates connection) 4 10 TX0d- 5 3 TX0d+ 6 11 RXI- 7 4 RXI+ 8 12 TX0+ 9 5 TX0- 10 13 VCC (5V) 11 6 TX+ 12 14 TX- 13 7 GND 14 15 RX+ 15 8 RX- I gained this information by testing the chip and the SKT16. If anyone has issues i would recommend they do the same. Cheers -- Stephen Leary