Programming 2708's

[Randy McLaughlin]

From: "lee davison" <leeedavison at yahoo.co.uk>
Sent: Saturday, June 25, 2005 6:49 PM

>>>  What programmer can I look for that has the ability to program a
>>> 2708?
>
> I have a Softy 2 that can do it if you're really stuck.
>
>> Not just that, the programming algorithm is different to most
>> other EPROMs. IIRC you have to program all locations in sequence,
>> giving each one a 1ms (IIRC) programming pulse, and repeat that
>> 50 times.
>
> Any bit in any byte can be individually programmed from 1 to 0.
> There are no sequence requirements, the programming pulse is one
> pulse of 50ms per location programmed.
>
>> You can't program odd locations like you can in later EPROMs.
>
> You can, it's EPROM microcontrollers like the 68705 that need to
> be programmed in sequence.
>
> Lee.

The 2708 can be programmed non-sequentially and the pulse can either be one
50ms or multiple shorter pulses that adds up to 50ms.  There are other
"fast" techniques where you write with a short pulse, read and rewrite until
all cells verify then run one more short pulse write.


Randy
www.s100-manuals.com