erd@tut.cis.ohio-state.edu (Ethan R. Dicks) (02/16/89)
In previous articles, many people put forth suggestions regarding speeding up IEEE transfers. I have not been able to locate one, but Motorola produced (produces?) a chip called the MC68488, an eight-bit I/O bus chip, designed for use with the 6809 which provides full IEEE-488 handshaking and supports the DMA used back in the 6809 days (I don't think it is of much use these days). This chip plus the two chip IEEE-488 buffer set (not the same chips used in the PETs, these chips came one for the data lines, one for the control lines), or the three chip IEEE-488 buffers used in the PETs will provide an IEEE connection, waiting for a peripheral bus to talk to. I have thought about building a prototype card for the C64 or the Amiga, but I have never been able to get a sample of this chip (distributors tend to like to sell $100+ orders) I have literature on this chip. If you are interested, reply and if there are enough requests, I will post a summary of the spec sheets. If there are not enough request, I will e-mail a summary. -ethan -- Ethan R. Dicks | ###### This signifies that the poster is a member in Software Results Corp| ## good sitting of Inertia House: Bodies at rest. 940 Freeway Drive N. | ## Columbus OH 43229 | ###### "You get it, you're closer.
dak@ut-emx.UUCP (Donald A Kassebaum) (02/16/89)
The older Pet and CBM computers used the old MC 488 buffers which handled 4 IEEE488 line, with and input and an output for each IEEE 488 signal. The IEEE 488 data line input whent to half of a 6520, and the output line when to the other half of the 6520. The control lines which were used went to the 6522. The newer IEEE488 buffers have a dirction pin associated with input/output. The mc68488 is indeed a nice chip, but it is a listener/talker. It is used in many Ieee488 instruments. In order to make it a controler, addition hardware is required to handle ATN, SRQ, IFC, REN and EOI in certain cases. It is too bad that MC didn't see fit to add these features to the chip. Dak
stephenc@tekgen.BV.TEK.COM (Stephen Coan ) (02/22/89)
In article <35528@tut.cis.ohio-state.edu>, erd@tut.cis.ohio-state.edu (Ethan R. Dicks) writes: > In previous articles, many people put forth suggestions regarding speeding > up IEEE transfers. I have not been able to locate one, but Motorola > produced (produces?) a chip called the MC68488, an eight-bit I/O bus chip, . . . > Ethan R. Dicks | ###### This signifies that the poster is a member in > Software Results Corp| ## good sitting of Inertia House: Bodies at rest. > 940 Freeway Drive N. | ## > Columbus OH 43229 | ###### "You get it, you're closer. The 68488 chip is buggy. It also adheres to the 1975 version of the standard, not the later versions (1978, 1980, 1987). The major test equipment manufacturers have given up on using this chip in new designs (Fluke, HP, Tektronix, etc.). I also would not recommend the NEC 7210 chip due to many problems in it as well. The bus does support bus speeds of up to 1Mbyte per second, usually with a DMA controller involved. The other choices avaiable are the TI-TMS9914A and the INTEL-8291A chips. The interface chips to the IEEE-488 most used are the 75160, 75161 chips by TI or National. My background is that I have been extensively involved in GPIB testing for Tektronix for 10 years and have worked with both TI and Intel in getting them to revise their chips to their current "A" versions. I have also participated in the generation of the newest IEEE versions of the venerable GPIB standard, the ANSI/IEEE Std 488.1 and 488.2 1987. If anyone wants details on problems, drop me a line and I'll send you information. That information does not need to be expounded here. Stephen L. Coan Tektronix, Inc Beaverton, OR 97077 stephenc@aice.bv.tek.com -- Steve Coan tektronix!tekgen!stephenc (503) 627-1794
izot@f171.n221.z1.FIDONET.ORG (Geoffrey Welsh) (02/24/89)
> From: stephenc@tekgen.BV.TEK.COM (Stephen Coan ) > Message-ID: <4125@tekgen.BV.TEK.COM> > > The 68488 chip is buggy. It also adheres to the 1975 version of the > standard, not the later versions (1978, 1980, 1987). You have to keep in mind that the IEEE-488 bus used by Commodore was a non-standard extension. > The bus does support bus speeds of up > to 1Mbyte per second, usually with a DMA controller involved. The Commodore implementations discussed here do handshaking via parallel I/O lines controlled by a 1 MHz 6502 (i.e. no hardware support beyond the MC3446 drivers). While discussing the mandated limits of IEEE-488 performance is certainly interesting, it isn't really applicable here. > The other > choices avaiable are the TI-TMS9914A and the INTEL-8291A chips. The > interface chips to the IEEE-488 most used are the 75160, 75161 chips by TI > or National. I'm not familiar with the TI or NSC chips (I may have been and forgotten since); the Intel chip set, while probably usable for a Commodore-oriented application, is far too expensive for most of the peoplelooking to play around in this field. > I have > also participated in the generation of the newest IEEE versions of the > venerable GPIB standard, the ANSI/IEEE Std 488.1 and 488.2 1987. > > If anyone wants details on problems, drop me a line and I'll send you > information. That information does not need to be expounded here. I don't suppose you could put me on the mailing list for a copy of those standards? I'd really appreciate being brought up-to-date. =========================================================================== Internet: Geoffrey.Welsh@f171.n221.z1.fidonet.org | 66 Mooregate Crescent Usenet: watmath!isishq!izot | Suite 602 FidoNet: Geoffrey Welsh on 1:221/171 | Kitchener, Ontario PunterNet: 7/Geoffrey Welsh | N2M 5E6 CANADA BBS: (519) 742-8939 24h 7d 300/1200/2400bps | (519) 741-9553 =========================================================================== | "I don't need a disclaimer. No one pays any attention to what I say." | =========================================================================== -- Geoffrey Welsh - via FidoNet node 1:221/162 UUCP: ...!watmath!isishq!171!izot Internet: izot@f171.n221.z1.FIDONET.ORG