andrewb@softway.oz (Andrew Bettison) (06/28/89)
Consider the following scenario: A system containing a very nonstandard proprietary bus populated with all manner of custom-designed cpu, memory and i/o cards. The designers wish to connect a number of said systems to an off-the-shelf file server or UNIX box via a LAN (distances up to 100m), but no off-the-shelf cards are available for their bus. They must build a card, and need help deciding what LAN to use and hence what chipset. Constraints: - not much real estate available on PCB layout; - they're writing the client software themselves, so simplicity is a definite plus; - need to minimise development time and costs; - cost of the end-product is no constraint (i.e. rich customers); Can anybody suggest some appropriate LANs for investigation? If so, how does one obtain the relevant technical info? Thanks in advance. -- Andrew Bettison andrewb@softway.sw.oz.au uunet!softway.sw.oz.au!andrewb Softway Pty Ltd ph +61-2-698-2322 fax +61-2-699-9174
rtm@tellab5.tellabs.CHI.IL.US (Roberto Michelassi) (06/30/89)
In article <1751@softway.oz> andrewb@softway.oz (Andrew Bettison) writes: >Consider the following scenario: > > A system containing a very nonstandard proprietary bus > populated with all manner of custom-designed cpu, memory and > i/o cards. [ stuff deleted ] >Andrew Bettison andrewb@softway.sw.oz.au uunet!softway.sw.oz.au!andrewb >Softway Pty Ltd ph +61-2-698-2322 fax +61-2-699-9174 Advanced Micro Devices makes a nice (but fairly expensive) LAN chipset. The base chip is the Am7990 LANCE chip, a 48 pin VLSI device that handles the transferring and formatting of Ethernet packets to and from memory. The LANCE is capable of directly accessing memory and can manage lists of data buffers in memory. Two other chips are required in order to interface to an Ethernet/Cheapernet LAN. They are the Am7992B Serial Interface Adapter (SIA) and the Am7995 Ethernet/Cheapernet transceiver. The LANCE is programmed using several registers and data structures that are in memory. The LANCE can manage rings of transmit and receive buffers auto- matically. What this means is that once the chip is initialized, packets are transmitted or received by simply adding them or removing them from the appropriate buffer ring. Another chip to consider is the INTEL 82590/82592 LAN controller. This chipset is much less expensive than the Am7990 but requires a bit more hardware and software effort. (An external DMA controller is required and software must manage the buffers). I hope that this is some help to you. Roberto.
bharat@hprnd.HP.COM (Bharat Singh) (06/30/89)
I recommend that you consider building a 802.3 based LAN with either ThinLan or AUI interface. Out of several available Lan controller chips (Intel 82586, National 8390, Seeq 8005, AMD Lance 7990 and Fujitsu 86950), the 86950 by Fujitsu is simplest in writing driver. It is also the cheapest among the bunch with almost comparative performance (or may be higher) to all others. To get tech info on this chip, you may contact Al Chiang at Fujitsu at 408-922-9637. -Bharat