At 1:22 AM -0600 12/8/2002, Jeff Walther wrote: >At 10:23 -0500 12/07/2002, Compact Macs wrote: > > > >>>out of the VIA1. Is that a custom Apple chip or something which is >>>more generally available? >> >>I'm pretty sure it's custom.
Originally the VIA was a version of the venerable 6522, later it was designed into larger custom chips that included other functions. I don't know off hand when they did that but I think the SE/30 would still have a discrete VIA chip. The 6522 is a common support chip designed for the 6502 processor family. > >>I had a mystery ROM in my collection and just identified it as an >>>SE/30 ROM. A local parts store (Howard Electronics) gave it to me >>>when they found that I was into Macs. The thing that puzzles me is >>>that this ROM bears four Atmel 27C512 chips which should add up to >>>256 Kbytes of storage. Yet the silk screening on the ROM says "512K > >>ROM SIMM". 512K ROM SIMM could simply refer to the maximum capacity of the SIMM and in this case 256K or less of actual ROM was needed. Your correct a 27C512 is 64KBytes so 4 of them are 256KBytes -- Clark Martin Redwood City, CA, USA Macintosh / Internet Consulting [EMAIL PROTECTED] "I'm a designated driver on the Information Super Highway" -- Compact Macs is sponsored by <http://lowendmac.com/>. Support Low End Mac <http://lowendmac.com/lists/support.html> Compact Macs list info: <http://lowendmac.com/lists/compact.shtml> The FAQ: <http://macfaq.org/> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/compact.macs%40mail.maclaunch.com/> --------------------------------------------------------------- >The Think Different Store http://www.ThinkDifferentStore.com ---------------------------------------------------------------
