I appreciate the reply, Ive been working with surface mount rom and ram chips for DSP processing for a couple years now so I know exactly what you are talking about. Ill do my best to source some chips. As for the wd92c32 chip I will start looking.
Thanks Doug -----"Compact Macs" <[EMAIL PROTECTED]> wrote: ----- >To: "Compact Macs" >From: Jeff Walther >Sent by: "Compact Macs" >Date: 08/04/2004 14:40 >Subject: Re: Soft "rom" question > >>From: >>Subject: Re: Soft "rom" question >>Date: Mon, 2 Aug 2004 21:31:03 -0500 > >>The nature of work I do for a living allows me access to a wide >variety of >>electronic components. I also have the ability to burn just about >any chip >>made. I find this topic fascinating and if there really is demand >for this >>I would love to offer my help. >> >>If you could give me a specific module form factor, rom size and >maybe a >>few manufacturer parts numbers off the chips I bet I could come up >with >>something. Nothing is too esoteric, If it was made Im willing to >wager I >>can find it. > >I have the ROM code for the IIci stored away on disk, and I'd be >happy to email it to you. > >To go into a bit more detail... > >I don't know what level of detail/complexity to discuss this, so >I'll stay to a simple level. If this is too simplistic and covers >already understood ground I apologize. > >The SE/30 ROM is 128K X 32. In other words it is 32 bits (4 bytes) >wide and has 128K addresses. The ROM module achieves this by using >four 128K X 8 chips in parallel. So the organization of the chips >on the ROM module is 128K X 8. This is a very common capacity and >organization for non-volatile memory chips (Flash, EEPROM, EPROM). > >The problem is that capacity and organization are not the only >parameters of a memory chip. Another factor is the package. The >package is the physical body in which the chip exists, and >determines >the spacing, placement, and organization of the metal pins, by which >one connects to the chip. > >Printed circuit boards are built to take specific chip packages at >specific locations. Even if you have exactly the correct chip, as >far as functionality goes, if it is in the wrong package, you can't >solder it onto the printed circuit board, because the chip's pins >won't fit onto the circuit board's pads or will be arranged in the >wrong order, or both. > >The SE/30 ROM module uses four 128K X 8 chips, but the two versions >of the SE/30 ROM module of which I am aware, use either a 44 pin >PLCC >package, or a 32 pin SOP package. > >Okay, I just checked Gamba's page > to refresh my >memory. Apparently there are three versions of the SE/30 ROM. >One >uses the PLCC44 chips, one uses the SOP32 chips and Gamba lists one >with PLCC32 chips as well. If anyone, has one of this latter type >of ROM SIMM, conversion would be relatively simple. I have never >seen one of the PLCC32 type. (John Snook, if you've got a PLCC32 >SE/30 module handy, I can supply the needed chips after all.) > >However, to convert one of the common PLCC44 or SOP32 types, one >would need four memory chips with 128K X 8 organization and in a >PLCC44 or SOP32 package. I'm not sure which of those two is more >common. I would guess the SOP32 package, because it's listed in >another spot on Gamba's page by itself. > >So the goal would be a FLASH, EEPROM or EPROM with a 128K X 8 >organization and in a PLCC44 or an SOP32 package. I do not know >specfic part numbers for any such chips, unfortunately. The chips >on the ROM modules themselves are Mask ROMs, so their part numbers >(e.g. HN62331) are not any real help. > >Anyway, if you can come up with a source of affordable SOP32 128K X >8 >programmable chips, that would do the trick, and as I wrote above, I >can supply the code files. I have no idea how many folks would be >interested. Many of the folks who have an interest are already >using >a IIci or IIfx ROM. > >Jeff Walther > >P.S. Do you know an affordable (~$1/chip) source of WD92C32 chips? >This is a Digital Data Separator in an 8 pin DIP package. I need a >few because I'm trying to clone the external floppy drive for the >old >Outbound Model 125 (Mac clone) laptop. > > >-- >Compact Macs is sponsored by . > >Support Low End Mac > >Compact Macs list info: >--> AOL users, remove "mailto:"; >Send list messages to: >To unsubscribe, email: >For digest mode, email: > >Subscription questions: >Archive:>m/> > > >--------------------------------------------------------------- >>The Think Different Store >http://www.ThinkDifferentStore.com >--------------------------------------------------------------- -- 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> --> 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 ---------------------------------------------------------------
