Re: [M100] REXCPM 2M vs 4M

[Jim Anderson]

> -Original Message-
> Correct Jim, it hasn't been fixed yet. After Easter I can get back to
> it.

That'll be awesome, thanks for the update!  For now, it's incentive to keep my 
CP/M file count from bloating out of control :)







jim

Re: [M100] REXCPM 2M vs 4M

[Philip Avery]

Correct Jim, it hasn't been fixed yet. After Easter I can get back to it.

Philip

On 26/02/2021 11:56 am, Jim Anderson wrote:

-Original Message-
For the record, I did end up successfully upgrading a 2M REXCPM to 4M
using the RMLV3216AGSA linked below.

This reminds me... did I miss an announcement, or is the release of a CP/M 
image for the 4MB REX with increased directory entries still pending?  The 
current image linked on http://bitchin100.com/wiki/index.php?title=M100_CP/M is 
CPM410.BK which is the same filename as I have, so unless it's posted somewhere 
else I guess it hasn't been fixed yet.







 jim

Re: [M100] REXCPM 2M vs 4M

[Jim Anderson]

> -Original Message-
> For the record, I did end up successfully upgrading a 2M REXCPM to 4M
> using the RMLV3216AGSA linked below.

This reminds me... did I miss an announcement, or is the release of a CP/M 
image for the 4MB REX with increased directory entries still pending?  The 
current image linked on http://bitchin100.com/wiki/index.php?title=M100_CP/M is 
CPM410.BK which is the same filename as I have, so unless it's posted somewhere 
else I guess it hasn't been fixed yet.







jim

Re: [M100] REXCPM 2M vs 4M

[Brian K. White]

For the record, I did end up successfully upgrading a 2M REXCPM to 4M 
using the RMLV3216AGSA linked below.


The only special note other than "how to desoldering alloy" and "how to 
drag solder" was that the epoxy holding the copper on the pcb is weak. 
Be exceedingly gentle wicking up the desoldering alloy, don't scrub, and 
even with gentle wiping, only move in the same direction as the the 
pads, don't wipe them sideways. Blot-lift-move-blot instead. One of the 
teeny pads for the sram shifted sideways on me even though I was being 
careful. I was able to nudge it back into place eever so carefully 
without breaking the trace and solder the new chip.


Other than that it was straightforward. The pin-1 corner is marked on 
the silkscreen, and there was nothing special to do, just solder the 
chip and load the same firmware, only using the 4M cpm file.


Thus do I publicly waive any hint of warranty on my rexcpm. ;)

Also the dlplus bootstrap option can be used for rxctst.DO too.
dl -b./rxctst.DO    and   RUN "COM:98N1EN"   and it runs all the tests 
on the rexcpm.


--
bkw


On 6/29/20 9:29 PM, Brian K. White wrote:


$56 for a single
https://www.digikey.com/product-detail/en/cypress-semiconductor-corp/CY62177EV30LL-55ZXI/428-3278-ND/2188331 



This looks compatible for $26 for a single
https://www.digikey.com/product-detail/en/renesas-electronics-america/RMLV3216AGSA-5S2-AA0/RMLV3216AGSA-5S2-AA0-ND/9650085 



$32 at Mouser
https://www.mouser.com/Semiconductors/Memory-ICs/SRAM/_/N-4bzpt?P=1z0w8ge

It even seems to have a lower standby current. The Cypress data sheet 
says 3uA and the Renesas says 0.6uA


If I buy one of these myself and solder it, will that be enough other 
than re-programming?


$26 is a lot, and I wouldn't expect you to buy 100 of them for $2400 
but, if I want it, and assuming a perfect solder job, is there 
anything else besides a reflash required to make it work?


Obviously, it's a given that all concept of warranty and liability 
goes out the window instantly.







--
bkw