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'[OT] ish EPROM Programming Specs'
1998\03\12@011254 by Jacques Vrey

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face
Hi to all

I'm looking at building a simple EPROM programmer for
the 2716 to 27512 EPROM's (All I need for now). I'll
probably use a PIC in there somewhere. So I was wondering
if anyone out there knows where I can get the programming
specs, or has them for me. I had a look around, I could
find the pinouts but that appears to be it.

TIA

Regards


Jacques Vrey
Iscor Steel Profile Products
Internal Post Point 74
PO Box 2
Newcastle
2940
South Africa
Tel: +27 (0)3431 48759
Fax: +27 (0)3431 48001
spam_OUTjvreyTakeThisOuTspamit.new.iscorltd.co.za
The views expressed above are not necessarily
those of Iscor Limited.

1998\03\12@012512 by Sean Breheny

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At 08:10 AM 3/12/98 GMT+2, you wrote:
>Hi to all
>
>I'm looking at building a simple EPROM programmer for
>the 2716 to 27512 EPROM's (All I need for now). I'll
>probably use a PIC in there somewhere. So I was wondering
>if anyone out there knows where I can get the programming
>specs, or has them for me. I had a look around, I could
>find the pinouts but that appears to be it.
>
>TIA
>

Programming these is quite straightforward. It basically just involves
applying valid address and data, power supply (5 volts and programming
voltage), and pulsing CE low for some predetermined amount of time, then
reading back the value to make sure it worked. If it didn't work, repeat
the process. If you have more than 25 reps, report an error and abort. For
specifics, check out http://www.amd.com

Good luck,
Sean
+--------------------------------+
| Sean Breheny                   |
| Amateur Radio Callsign: KA3YXM |
| Electrical Engineering Student |
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1998\03\12@083610 by Morgan Olsson

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At 01:23 1998-03-12 -0500, you wrote:
{Quote hidden}

There are a lot of algorithms to increase reliability.
A common method is to program and verify short times until it reads
correct, then overprogram a certain time.  That assures a margin.
Verification should best be done at both Vdd min and Vdd max.
/Morgan
/  Morgan Olsson, MORGANS REGLERTEKNIK, SE-277 35 KIVIK, Sweden \
\  mrtspamKILLspaminame.com, ph: +46 (0)414 70741; fax +46 (0)414 70331    /

1998\03\12@134217 by Mike Keitz

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On Thu, 12 Mar 1998 01:23:56 -0500 Sean Breheny <.....shb7KILLspamspam.....CORNELL.EDU>
writes:
>At 08:10 AM 3/12/98 GMT+2, you wrote:
>>Hi to all
>>
>>I'm looking at building a simple EPROM programmer for
>>the 2716 to 27512 EPROM's (All I need for now). I'll
>>probably use a PIC in there somewhere. So I was wondering
>>if anyone out there knows where I can get the programming
>>specs, or has them for me. I had a look around, I could
>>find the pinouts but that appears to be it.

There are 3 pricipal algorithms:

* Single 50 ms pulse - Used only on very old EPROMs, 2716, 2732, maybe
some 2764.  Set up address and data, and apply a 50 ms programming pulse.

* "INTELligent Algorithm" - Apply repeated 1 ms pulses until verify, then
"overprogram" with a pulse 3x the total length of previously applied
pulses.

* Quick pulse - Apply repeated 100 us pulses until verified *at Vdd = 6V
to 6.5V*

Most newer devices can use either the quick pulse or the INTELligent
method, the former being faster but needing adjustable Vdd.

Programming voltages of 25, 21, and 12.5V are popular.  I think just
about all CMOS (27CXXX) EPROMs use 12.5V.  Usually the voltage is marked
on the chip.  The 2732 and 27512 devices share the programming voltage
input with the OE pin, so a more complicated switch is needed to change
from program to verify mode.  The others have a dedicated Vpp pin so all
programming signals are TTL-level.

Data sheets from any EPROM maker, e.g. AMD or Microchip, will have
complete details.  Finding data on the older small chips can be hard.
The 27C64 is the smallest I'd recommend for new designs, even if 2K or
less space is actually needed.

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'[OT] ish EPROM Programming Specs'
1998\07\30@174447 by Morgan Olsson
picon face
At 01:23 1998-03-12 -0500, you wrote:
{Quote hidden}

There are a lot of algorithms to increase reliability.
A common method is to program and verify short times until it reads
correct, then overprogram a certain time.  That assures a margin.
Verification should best be done at both Vdd min and Vdd max.
/Morgan

1998\07\30@193839 by Mike Keitz

picon face
On Thu, 30 Jul 1998 23:35:44 +0200 Morgan Olsson <EraseMEmrtspam_OUTspamTakeThisOuTINAME.COM> writes:
>At 01:23 1998-03-12 -0500, you wrote:

>>Programming these is quite straightforward. It basically just
>involves
>>applying valid address and data, power supply (5 volts and
>programming
>>voltage), and pulsing CE low for some predetermined amount of time,
>then
>>reading back the value to make sure it worked.

The 2732 and 27512 share the programming voltage with the output enable
pin.  So these require a more complicated circuit that can drive the pin
relatively quickly either 0V, 5V or programming voltage.  The other sizes
have a dedicated pin for programming voltage that can be left at the high
voltage through the entire process.  Sizes up to 4Mbit program
essentially the same as the other ones, just a 32 pin socket and more
address lines are needed.  Just about all EPROMS 2764 and larger use
12.5V for programming.  On the older ones, 21.5 or even 25V is needed.  A
LM317 circuit with switchable resistors can accomodate the different
voltages.

>There are a lot of algorithms to increase reliability.
>A common method is to program and verify short times until it reads
>correct, then overprogram a certain time.  That assures a margin.
>Verification should best be done at both Vdd min and Vdd max.

There are 3 major algorithms.  The first just applies a single 50 ms
pulse to program each byte.  It is used only on the smallest/oldest
chips, and can damage new ones.  Even on those, it is quite slow (20
bytes/sec).  The one Sean describes using up to 25 1 ms pulses then a
single 3x "overprogram" pulse is often called the INTELligent Algorithm
(especially by Intel, which I believe introduced it).  It should work on
most all chips, even the old ones.  The newest algorithm is the
Quick-Pulse, which uses 100 us pulses and no overprogram pulse.  Only
some of the newer, larger EPROMs are rated for it.  Also the chip's Vdd
voltage needs to be raised during the process, making the programmer more
complicated.  A simple programmer should be able to get by with the
INTELligent Algorithm only, with maybe the single pulse algorithm for the
small chips.  It would be nice to verify at several voltages, but for
hobby application it isn't too necessary.


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