Date   : Sat, 29 Oct 2005 10:34:15 +0100
From   : "A. J. Davis" <mail@...>
Subject: Re: (BBC-Micro) Possible EPROM???

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. 

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.

If you're using a PC EPROM programmer, such as the Willem, you can just 
set the offset to compensate.