Path: utzoo!mnetor!uunet!pcrat!rick From: rick@pcrat.UUCP (Rick Richardson) Newsgroups: comp.arch Subject: Re: Cost of Low-end RISCS for RTC (was Re: RISC != real-time control) Message-ID: <492@pcrat.UUCP> Date: 6 May 88 15:23:34 GMT References: <1521@pt.cs.cmu.edu> <1532@pt.cs.cmu.edu> <476@pcrat.UUCP> <833@imagine.PAWL.RPI.EDU> <3444@omepd> Reply-To: rick@pcrat.UUCP (Rick Richardson) Organization: PC Research, Inc., Tinton Falls, NJ Lines: 37 Keywords: RISC, real-time In article <3444@omepd> mcg@iwarpo3.UUCP (Steve McGeady) writes: >Now, this is three times the performance and 10x the cost of Mr. Richardson's >request, but look more closely. One could: > a) run the chip at 16Mhz (or 10, for that matter); > b) put 1Mb of relatively inexpensive 2 or 3 wait-state memory on > the bus; > c) buy the chips in lots of, say, 1,000,000, and expect a healthy > discount (I believe this was stated in Mr. Richardson's original > article); >This would reduce the cost (and performance) of the overall system to the >area that Mr. Richardson is investigating. > >If one was really going to buy chips in large lots. You still have slightly >higher support costs because of a 32-bit bus, rather than 16, but that's >not such a big deal. But: Widgets in plastic boxes don't pass FCC at high clock rates without a lot of layout headaches and extraneous R's and C's. Keep the clock down around 4 Mhz! The bus width is a big deal. We're talking parts count here. Ideally: 1 CPU, 1 RAM, 1 ROM, 1 Glue, and peripheral chips. The 16 bit bus gets the nod only because RAM/ROM requirements exceed current state of the art in RAM/ROM chips. Go beyond 128K ROM and you're talking two chips. Go beyond 32K (static) RAM and you're also talking two chips. I'm looking at a bunch of consumer type applications that have outgrown the 8088 level of CPU performance, and are moving into the 64K to 128K bytes range of RAM, and the 256K to 512K bytes range of ROM. -- Rick Richardson, President, PC Research, Inc. (201) 542-3734 (voice, nights) OR (201) 834-1378 (voice, days) uunet!pcrat!rick (UUCP) rick%pcrat.uucp@uunet.uu.net (INTERNET)