[Q] How to program 2816 EEPROM?
Ken Yap
in my data book but no information other than a list of features and
pinout. Can I program them with the normal programming algorithm on my
EPROM programmer? How come people didn't use these more widely for
EPROM emulation instead of SRAM+battery?
Thanks, Ken
k...@syd.dit.csiro.au
Don McKenzie
: I've got these 2816s from an old PCB. They're noted as 2716 compatible
: Thanks, Ken
: k...@syd.dit.csiro.au
Hi Ken, as it's Sunday and I don't have access to my usual data library,
I believe what you have is a pin compatilble 2K EEPROM.
If that is the case then it is pin compatible with a 6116 static ram, and
almost pin compatible with with a 2716 EPROM.
Upmarket burners that support the chip type will burn them fine. If your
programmer menu doesn't support it, don't try it as the 12.5, 21, or 25
volts that is selected will destroy it.
The real reason they aren't widely used for the application you mentioned
is that it takes a little extra time to program one of these babies. Not
much, but it can't be done with normal CPU write cycles.
Get a copy of my promo disk below. It covers a little bit of EEPROM
progamming and lots of other stuff.
Don...
Low Cost DIY PCB's for PICs & COM1/LPT1 PC I/O Interface Kits ;!
Don McKenzie. 29 Ellesmere Cres., Tullamarine. 3043 Australia ;@
Tel +61 3 9338 6286 Mobile +61 019 939 799 don...@tbsa.com.au ;#
Check My Promo Disk at http://rasi.lr.ttu.ee/~sis/mirror/don/ ;$
Type: 'finger don...@tbsa.com.au|more' for more information. ;%
Ray Jones
>I've got these 2816s from an old PCB. They're noted as 2716 compatible
>in my data book but no information other than a list of features and
>pinout. Can I program them with the normal programming algorithm on my
>EPROM programmer? How come people didn't use these more widely for
>EPROM emulation instead of SRAM+battery?
>
> Thanks, Ken
> k...@syd.dit.csiro.au
Ken,
The 2816 is NOT an EPROM, it is an EEPROM.
This EEPROM is pin for pin compatible with the 2Kx8 6116 static ram and
can be read in much the same way.
To write to it however takes several milliseconds typically.
The typical method for writing is to write a new data byte to the EEPROM,
just as you would to normal RAM and then read back the same location
until the value read back agrees with the value just written.
Whilst the data is being written into the EEPROM's cell, the read-back
data will be modified by complementing the MSB of the new data byte.
Therefore, no special voltages are needed to program this beast, just
a programming routine that is aware of the read-back re-quirement.
Hope this helps.
---------------------------------------------------------------------------
Ray Jones TO4(eng) Bureau of Meteorology \
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Gray Creager
>I've got these 2816s from an old PCB. They're noted as 2716 compatible
>in my data book but no information other than a list of features and
>pinout. Can I program them with the normal programming algorithm on my
>EPROM programmer? How come people didn't use these more widely for
>EPROM emulation instead of SRAM+battery?
>
> Thanks, Ken
> k...@syd.dit.csiro.au
Actually, the _REAL_ reason that EEPROM devices didn't make it into your generic PC is because
of cost. EEPROMs are a technology that allows for 5V in circuit reprogramming a byte at a
time. Flash is similar, but requires that operations be performed on large blocks. This means
that EEPROMs are byte-alterable and Flash EEPROMs are not. Flash also has smaller bit cells,
therefore much higher densities and lower cost per bit. EEPROMs are available up to 1Mbit, but
these are BIG diesizes and are quite a bit more expensive per bit, than Flash. SRAMs by
comparison are cheap. Since there was a need to have batteries for the real-time clock
circuitry anyway, cheaper SRAM chips (which _never power down_) got the nod over EEPROMs (too
expensive) and Flash (expensive and much bigger than needed). EPROMs would work, but you
couldn't ever change them in system.
To answer your other questions:
the 2816 (i.e. X2816A, X2816B, or X2816C which have been available from Xicor over the years)
is a JEDEC pinout. To program the device, you can have a /CE or /WE controlled write cycle.
When the internal nonvolatile storage cycle is underway, there is a typical 5ms (max. 10ms)
delay when the chip "shuts out the outside world". You don't send any high voltage pulses to
program the device... just treat it like an SRAM, but implement a 5ms - 10ms loop after
loading data on the page.
Here's your pinout (X2816C = X2816B = X2816A... only X2816C is still available from my
company)
+---o---+
A7 -|1 24|- Vcc
A6 -|2 23|- A8
A5 -|3 22|- A9
A4 -|4 21|- /WE
A3 -|5 20|- /OE
A2 -|6 19|- A10
A1 -|7 18|- /CE
A0 -|8 17|- D7
D0 -|9 16|- D6
D1 -|10 15|- D5
D2 -|11 14|- D4
Vss-|12 13|- D3
+-------+
The X2816C has a 16 byte page write operation that will allow you to reprogram the entire
array in about 640ms (typically). Almost all EPROM programmers will support these old devices.
If you need data sheets or more info about these devices (I'm assuming that there is a good
chance that you have Xicor parts, but any of the competitor devices should be just about
identical), try Xicor's website. In particular, appnote AN54 will be of use to you. You can
also get this app note or data sheets from our FaxBack system at (408) 954-1627 (this won't
work for international numbers, but you can get any of our literature via e-mail on our
website).
I hope this helps.
Gray Creager
Applications Engineer
Xicor, Inc.
http://www.xicor.com
http://www.scruznet.com/~gcreager/hello.htm
Don McKenzie
: k...@syd.dit.CSIRO.AU (Ken Yap) wrote:
: >I've got these 2816s from an old PCB. They're noted as 2716 compatible
: >in my data book but no information other than a list of features and
: >pinout. Can I program them with the normal programming algorithm on my
: >EPROM programmer? How come people didn't use these more widely for
: >EPROM emulation instead of SRAM+battery?
: >
: > Thanks, Ken
: > k...@syd.dit.csiro.au
: Ken,
: The 2816 is NOT an EPROM, it is an EEPROM.
Hi Ray, and Ken again. I don't think Ken said it was an EPROM, at least I
didn't read it that way. He uses 'EEPROM' in the subject matter, but I
thought your answer was fine Ray.
Ken, your $49 Z80 development system is in todays mail.
po...@netins.net
Did you know where we could find the SemiConductors chip for sale?
What newsgroup should I subscribe or what BBS we could connect?
Currently I am looking for Diode Manufacture Motorola P/N :P6SMB47A.