[Tech] Rom Access times

[guddler]

[ukvac] [Tech] Rom Access times
Does anyone know what the access time should be set to for reading/writing a
"27C256" eprom please (sorry, i don't know the make, the is a square lloking
S printed on them). I'm trying allsorts and just getting errors when i try
and read them. Could this mean knackered roms?

TIA,
Guddler



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[JCRS]

Re: [ukvac] [Tech] Rom Access times
S in a Square.. isnt that Thompson .. which proberly doesnt make sense

 

[guddler]

RE: [ukvac] [Tech] Rom Access times
Not really too sure what it was as the sticker was partly over it. Anyway,
on extracting ALL the roms (okay, OT as this is a Pinball i'm talking
about), i discovered a bent pin on one of the ICCs.

Turned out to be the voltage pin on one of the sound roms. Funnily enough
when i straightened it out and refitted it all the missing sounds can now be
heard in all their glory, so i don't much care now why my burner couldn't
read them properly.

Thanks for the replies (on and off list) though anyway.

Guddler.

> S in a Square.. isnt that Thompson .. which proberly doesnt make
> sense



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[John Bennett]

[ukvac] Re: [Tech] Rom Access times
Signetics.

See handy link:

http://www.plasma-
online.de/english/identify/picture/index_logochip.html

:-M



DATA Imported from archives: originally posted by (mike@mailnet.co.uk)

 

[John Bennett]

Re: [ukvac] [Tech] Rom Access times
In article <OKEAKKLKNLLNCFCBKDFDEEJJCEAA.martin@guddler.com>, Guddler
<martin@guddler.com> writes
>Does anyone know what the access time should be set to for reading/writing a
>"27C256" eprom please (sorry, i don't know the make, the is a square lloking
>S printed on them). I'm trying allsorts and just getting errors when i try
>and read them. Could this mean knackered roms?

If in doubt try the slowest programming algorithm. Or erase the ROM and
do a zero check. The average read time of a modern EPROM should be
either 250nS or 150nS. (Probably) Some simple or vintage EPROM
programmers sometimes struggle with high impedance address/data lines
not draining residual charge fast enough to read correctly. I
occasionally had to disable the fast program algorithms on my first
programmer.

--
Clive Mitchell



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DATA Imported from archives: originally posted by Clive Mitchell (clive@emanator.demon.co.uk)