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'Serial Ram Chips?'
1996\04\30@210140 by Peter Homann

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Hi,

Does anyone know if there are any large (> 2KBytes) ram chips that
are serial addressable. I've seen that there are quite a few
EERAM chips, and quite a few 256 Byte chips.

I have a data logging application that needs 8KB -32 KB of RAM.

Thanks,

Peter.
--
_______________________________________________________________________
Peter Homann   email: spam_OUTpeterhTakeThisOuTspamadacel.com.au       Work : +61 3 9596-2991
Adacel Pty Ltd                                   Fax  : +61 3 9596-2960
250 Bay St, Brighton 3186, VIC, AUSTRALIA      Mobile :     014 025-925


'Serial Ram Chips?'
1996\05\01@105656 by Thomas Coonan
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>EERAM chips, and quite a few 256 Byte chips.
>
>I have a data logging application that needs 8KB -32 KB of RAM.
Dallas Semiconductor, of course, makes loads of NV-SRAM but mostly
parallel.  They also have the support chips which turn regular
SRAMs into NVs by inserting them in the Vcc pins.  They have a
serial 16-pin NV-Ram called "EconoRAM".  They have NV-RAMs that are
SIPs and stand up on end (if that helps).

XICOR makes a much smaller EEPROM which *also* has a shadow RAM
feature (you write to the SRAM and it automatically transfers
it to EEPROM on power down).

Phillips makes, for example, 256B I2C device PCF8570..

BENCHMARQ is another NV-RAM vendor.

I'd like to hear what you end of with.

.....Thomas.CoonanKILLspamspam@spam@Sciatl.com

1996\05\01@133623 by Reginald Neale

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>Hi,
>
>Does anyone know if there are any large (> 2KBytes) ram chips that
>are serial addressable. I've seen that there are quite a few
>EERAM chips, and quite a few 256 Byte chips.
>
>I have a data logging application that needs 8KB -32 KB of RAM.
>
>Thanks,
>
>Peter.
>--
>_______________________________________________________________________
>Peter Homann   email: peterhspamKILLspamadacel.com.au       Work : +61 3 9596-2991
>Adacel Pty Ltd                                   Fax  : +61 3 9596-2960
>250 Bay St, Brighton 3186, VIC, AUSTRALIA      Mobile :     014 025-925

Two companies who are currently advertising this kind of device:

EXEL at http://www.exel.com

XICOR at http://www.xicor.com

Reg

.....................Reg Neale.....................
"Ignorance is a renewable resource"   P.J. O'Rourke

1996\05\01@162503 by Michael S. Hagberg

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>Hi,
>
>Does anyone know if there are any large (> 2KBytes) ram chips that
>are serial addressable. I've seen that there are quite a few
>EERAM chips, and quite a few 256 Byte chips.
>
>I have a data logging application that needs 8KB -32 KB of RAM.
>
>Thanks,
>
>Peter.

Digi-Key (http://www.digikey.com) sells microchip and national serial eeproms
upto 16K bits (2K bytes). These devices are listed in the manufactures
data books as upto 64K bit versions.  Upto 8 devices can be daisy chained
on the same I/O.  Best of all they are 8 pin dip or surface mount.

download data specs from microchip.

michael

1996\05\01@175823 by Peter L. Taylor

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-- [ From: Peter L. Taylor * EMC.Ver #2.5.02 ] --


> >Does anyone know if there are any large (> 2KBytes) ram chips that
> >are serial addressable. I've seen that there are quite a few
> >EERAM chips, and quite a few 256 Byte chips.
> >
> >I have a data logging application that needs 8KB -32 KB of RAM.
> >
> >Thanks,
> >
> >Peter.
>
> Digi-Key (http://www.digikey.com) sells microchip and national serial eeproms
upto 16K
> bits (2K bytes). These devices are listed in the manufactures data books
as
> upto 64K bit versions.  Upto 8 devices can be daisy chained on the same
I/O.
> Best of all they are 8 pin dip or surface mount.
>
> download data specs from microchip.
>
> michael
>

National Semiconductor makes a 4M/8M bit serial flash ram part.  The part
numbers are: NM29A040/080.  The data sheet is one their web page (www
.natsemi.com/), or I could e-mail it to anyone interested.  The parts come
in a 28 pin SOIC or PLCC.  Only 6 pins are used;  the die must be really big
.

The only gotchas of this part are: 1)It is National Microwire compatible,
which isn't necessarily Microchip SPI compatible, 2)Before using the part
you have to read the upper block to find any bad blocks that shouldn't be
used.

If anyone figures out how to use the Microchip SSP port, in SPI mode, with
this part, please let me know.  As far as I can figure, the only way to
interface to it is use three port lines, and bypass the SSP module.

Peter Taylor
TransEra Corp.

1996\05\01@181241 by Scott Dattalo

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Peter Homann wrote:

> I have a data logging application that needs 8KB -32 KB of RAM.
>

Peter,

Parallax has an app note that interfaces a PIC16C55 to a 1Mb X 1 Dynamic
Ram chip. You can get this app note (and all of the rest of their app
notes) via ftp:

ftp://ftp.parallaxinc.com/pub/acrobat/picapps.pdf

Their home page is at

http://www.parallaxinc.com/

This approach certainly meets your 32K X 8 = 256k bit memory requirements.
However, it sucks up 15 I/O pins in the process. (Actually, you could get
by with using only 12 in your application.) This is more than a serial
interface, but less than a standard parallel interface.

Scott

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