Date   : Wed, 02 Nov 2005 19:51:11 +1100 (EST)
From   : Peter Craven <cjl_craves@...>
Subject: Re: Possible EPROM???

Well does anyone know how to:-

>'The only thing to remember is to put your ROM file
> at the 'end' of the EPROM.

on a Solidisk EPROM Progeammer?????






--- Jules Richardson <julesrichardsonuk@...>
wrote:

> A. J. Davis wrote:
> > Peter Craven wrote:
> > 
> >> Hello
> >>
> >> Can a the following EPROM be used in a Master
> >> Computer:
> >>
> >> The 27C512-90 is a 64k x 8 bits 90ns CMOS EPROM
> with a
> >> transparent glass window allowing the device to
> be
> >> erased and written over multiple of times by the
> >> programmer.
> >> Features:    
> >>
> >>    * 5V +/-10% Supply Voltage in Read Operation
> >>    * 90ns fast access time
> >>    * Low power consumption: Active Current 30mA;
> >> Standby Current 100ľA
> >>    * Programming voltage: 12.75V +/-0.25V
> >>    * Programming time: 6 seconds (Presto IIB
> >> Algorithm)
> >>    * Electronic signature
> >>    * Ideally suited for microprocessor systems
> >>    * Organisation: 65,536 x 8 bits
> >>    * UV Erasable
> >>
> >> Cat No.     Z9359
> >> Category:     ICs - EPROMS
> >> Support:     27C512-90 64k x 8 90nS EPROM (Z9359)
> >>
> >>
> >> Dr Peter Craven (MBBS Uni. of Qld)
> >>
> >>  
> >>
> > I have some AMD 27C512-120 which work ok.
> 
> I certainly expect it's electrically compatible...
> 
> > The only thing to remember is to put your ROM file
> at the 'end' of the 
> > EPROM.  So, if you have a 16k ROM image the first
> 48k must be blank.  
> > This is what I found when putting a 16K Wordwise
> image onto a 32k chip 
> > anyway.
> 
> Hmm, I guess that makes sense - the Master
> *probably* happens to tie the 
>   top few address lines high
> 
> Differences between the typical 272128 (16K x 8) and
> the 27512:
> 
> pin  27128  27512
>   1    vpp    A15
> 22    -oe    -oe / vpp
> 27    -pgm   A14
> 
> ... so for normal operation -oe (pin 22) will be the
> same between both 
> devices (it just has a dual function on the 27512
> for programming 
> conditions).
> 
> pin 27 - A14 on the 27512 - will always be held high
> by the Master 
> because it expects that to be the pin which is
> active low when 
> programming and high during normal operation.
> 
> pin 1 is the strange one, beause I'm surprised the
> Master doesn't tie 
> vpp to 0V for the expected 27128 device (and so for
> a 27512 A15 would be 
> low and Master would end up addressing the chip in
> the second quarter of 
> the chip's address space, not the last quarter).
> Maybe the EPROM specs 
> say that vpp should be set to the programming
> voltage during programming 
> and 5V otherwise, then things would work. Or maybe
> it's a jumper change 
> on the Master board?
> 
> cheers
> 
> Jules
> 
> 



Dr Peter Craven (MBBS Uni. of Qld)

12 Treacher St

Mt Gravatt

QLD 4122

Ph (H): (07) 3349 0820









               
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