[sdiy] Partitioning feature of the DS1630AB..

[Jean-Pierre Desrochers]

Thank You very much Jason,

 

That is a very instructive explanation of the DS1630 possible partitioning behaviour…

 

Since I need to replace the DS1630AB used in my TDS350 and don’t know
how Tektronix is using it I finally find the dremeling of an old DS1630 (Y or AB)
to be the best way  to get rid of the inner battery but keeping the partitionable SRAM.
I’ll buy 2 or 3 of these old IC then salvage a first one to see how and where the inner battery cell
is connected inside. Then ‘correctly’ dremel another one and do the cell tab’s surgery to use external leads to
a more robust 3V lithium like a CR123A placed in an holder.

 

This will be my final choice..

 

 

De : Jason Tribbeck [mailto:jason at tribbeck.com] 
Envoyé : 1 mai 2021 15:19
À : Jean-Pierre Desrochers
Cc : synth-diy mailing list
Objet : Re: [sdiy] Partitioning feature of the DS1630AB..

 

Hi,

 

I'd not seen a partitioned ram system before I looked at the datasheet for the DS1630AB.

 

It's method to add write protection for partitions of the memory, and in order to activate it, you need to send a particular nibble sequence to the top 4 bits of the address (A11 to A14), using read cycles. There are 16 partitions, each equal in size in memory (so each are 2Kx8).

 

The sequence needs to be F, E, 7, 7, 3, 9, C, E, 7, 3, 9, 4, 2, 4, A, 6, 9, 1, 0, 5 - and then send 4 nibbles that enable / disable writing to each of the 16 partitions (1 = deny write; 0 = permit write).

 

It seems like you can get the partition and battery backup control in (obsolete) DS1610 as well.

 

If you needed to implement it in something a bit more modern, then you'll need to see if there is something that does something similar (I've not found one yet), or implement it in something like a CPLD.

 

If you don't implement it, then all of your memory will be writeable, which could cause problems for systems that are expecting the memory to be read-only in certain areas.

 

Unfortunately, my quick scan of the datasheet does not indicate if the memory defaults to being writeable or not. It could potentially retain the settings from the last time the partitioning was configured (as it has access to the battery backup).

 

On Sat, 1 May 2021 at 15:05, Jean-Pierre Desrochers <jpdesroc at oricom.ca> wrote:

What is the difference between the partitioning feature of a Dallas NVRAM DS1630AB
and a standard 32k x 8 SRAM (regardless the non-volatile option) ?

Both running at the same speed and 5v voltages ..

Can the DS1630AB be replaced by a standard SRAM of the same size ?

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