Extended Memory module and HP-41CX

[grsbanks]

Quick question...

Looking at the leaflet that comes with the HP-82181A Extended Memory module, it says:

Quote:The HP 82181A Extended Memory Module provides an additional 238 registers (1,666 bytes) for use with the HP-41C or the HP-41CV.

Obviously you need the HP 82180A Extended Functions Module to be able to use it, so why can this not be used with the HP-41CX, which has the X-Func module built in? Or is it maybe a case of this particular module being produced before the 41CX was released, hence not mentioning it?

[Jlouis]

Don't know about the leaflet, but you sure can use x mem in the CX.

Actually you can use up to 2 x mem module in the CX.

Cheers[/b]

[grsbanks]

(12-16-2018 06:47 PM)Jlouis Wrote:  Don't know about the leaflet, but you sure can use x mem in the CX.

That was my gut feeling too. The DM41(L) even has one built in. The fact that the leaflet doesn't mention it had me scratching my head.

(12-16-2018 06:47 PM)Jlouis Wrote:  Actually you can use up to 2 x mem module in the CX.

Yes, of course, as on any of the 41C series. That gets you 600 registers of X-Mem.

[Garth Wilson]

It's extra nice to have two of them built into one shell, to take only one port! I guess I felt I couldn't justify the expense back when EduCalc was selling them new, but I happened to find one for a lowish price on eBay years ago. For the c and cv, you could also get triple modules, ie, Extended Functions / Extended Memory plus two Extended Memory modules. Related, I also have a double module that's the Extended I/O built into the HP-IL module, and then also Diego's Clonix-D with a bunch of Rom module images in its flash.

[grsbanks]

(12-16-2018 08:15 PM)Garth Wilson Wrote:  It's extra nice to have two of them built into one shell, to take only one port!

https://s3-eu-west-1.amazonaws.com/xferp...blxmem.pdf

[Gene]

The X-memory modules, etc. were introduced some time before the HP-41CX, so this is likely a result of timing. Helps pin down a range for when the module/booklet were produced.

It **might** be an oversight right near the time the HP-41CX was made, but I suspect the former.

[rprosperi]

(12-16-2018 08:32 PM)Gene Wrote:  The X-memory modules, etc. were introduced some time before the HP-41CX, so this is likely a result of timing. Helps pin down a range for when the module/booklet were produced.

Exactly correct. The Summer '83 EduCALC catalog (#16) lists the Extended Fns/Mem module and Ext Mem modules on p.5 for the 41C/41CV, some months before the 41CX was introduced.

Any reason to dig through Jake's awesome set of EduCALC catalogs is a good one. They're a bit like our own private little historical society resource for topics like this.

Jake's DVD, recently expanded to include all the EduCALC catalogs, plus a bunch of period HP catalogs, brochures and other HP newsletters (e.g. Key Bits Dealer's newsletter, BASIC Exchange, and others) is available here:

http://www.pahhc.org/ppccdrom.htm

[Sylvain Cote]

HP-41 Memory Map (all addresses are inclusive)

Code:

Empty Space :  16 registers from 1008 (0x3F0) to 1023 (0x3FF)
X-Memory #2 : 239 registers from  769 (0x301) to 1007 (0x3EF)
Empty Space :  17 registers from  752 (0x3F0) to  768 (0x300)
X-Memory #1 : 239 registers from  513 (0x201) to  751 (0x2EF)
Empty Space :   1 register  from  512 (0x200) to  512 (0x200)
Main Memory : 320 Registers from  192 (0x0C0) to  511 (0x1FF)
X-Fnc/X-Mem : 128 registers from   64 (0x040) to  191 (0x0BF)
Empty Space :  48 registers from   16 (0x010) to   63 (0x03F)
Status Regs :  16 registers from    0 (0x000) to   15 (0x00F)

[Allen]

(12-16-2018 06:40 PM)grsbanks Wrote:  

Quote:The HP 82181A Extended Memory Module provides an additional 238 registers (1,666 bytes) for use with the HP-41C or the HP-41CV.

I have 2 versions of the XMEMORY pamphlet dated December 1981 and October 1984 and neither mentions compatibility with the 41CX. I'm guessing the image above is from the 1981 pamphlet. But, I agree with the others, the 41CX did get the Extended Functions and TIME module built in, but definitely needed the 2 XMEM modules to complete the extended memory registers.