What IS this and who is Dave?

[Geoff Quickfall]

In the title.

I was working on three are card readers today and found this in the box with them. So of course I pulled it apart and inserted into a bare bones fullnut 41CX. I was given this at an HHC in the past but can't remember when, by whom and what it is/was.

Looks like a ram box with switching but plugging it in and the calc responds normally and doesn't recognize the unit in any catalog.

Changing the dip switches causes no effect or calculator freeze with a flashing display of nonsense characters.

So without furthe ado:

[hth]

Those are EPROMs, a 2732 for the lower 8-bits (L8) and a 2716 for the upper 2-bits packed into the bytes (U2). This is the original way to represent HP-41 ROM pages in EPROMs.

According to the label, it is the labels ROM for the David Assembler. It contains all the mainframe entry points to be used with the David Assembler. MNFR=mainframe I suppose.

David is David A. van Leeuwen, the author of it.

I suppose it is an EPROM box, which make I do not know, I have never seen any such device in real life, never could afford one back then.

I have no idea how to use either the ROM or the EPROM box, you probably need to have the David Assembler to make any use out of it, if it still works.

Håkan

[Gene]

The David Assembly ROM is in the 41CL rom load:

0x01F DAVID-2C DAVA 2 David Assembler 2C 0x3166EFBA

The manual is on TOS. Search for "David" and it pops right up.

The rom (the manual says) have five functions:

ASSM
REG>BUF
BUF>REG
DISTOA
BEG/END

I would suggest pulling the manual down. :-)

[Geoff Quickfall]

Thanks!

That would explain the takeover function on a couple of dip switches.

So off to the CL now!

Geoff

[Geoff Quickfall]

Exploring the box.

By selecting the dip switches I have discovered that DAVA; the David-Assem is built into the box.

It is recognized and contains:

• ASSM
• BEG/END
• BUF/REG
• DISTOR
• REG>BUF
• MNFR-LBLS
  

In cat 2 the first five are a subset of DAVID-ASSEM. The MNFR-LBLS follows the DAAVID-ASSEM in the cat 2 scroll.

So the 4K ROM image is not required as it is onboard.

More reading to follow...

Fixed two card readers today, one for me and another for a forum member. Now to enhance the spice chapter in the book.

[Didier Lachieze]

This looks like a HHP-PE (Portable EPROM). You’ll find a QRG and set-up instructions on TOS.

[Geoff Quickfall]

Thanks Didier!

Been playing with it all night. Looks like David-Assembler has been loaded into the upper and lower EPROMs.

Now I have a CL with the ROM image DAVA which contains the the David-Assembler so no need for the EPROMs to contain it.

Can one erase the EPROMs?

I cannot get the HHP to recognize the 12, XEQ "XROMTST" function. Would it have been erased or would the dip switches be configured at the factory for this built in function to work.

Obviously something is working as I have two full copies of the David-Assem.

Cheers, geoff

[Sylvain Cote]

Hello Geoff,

(03-24-2017 09:06 AM)Geoff Quickfall Wrote:  Can one erase the EPROMs?

I am assuming that you already know this, but yes it can be erased with a UV light box.
MCUmail located at Richmond BC sell this EPROM eraser
I also have one and can erase them for you if you want.

(03-24-2017 09:06 AM)Geoff Quickfall Wrote:  Would it have been erased or would the dip switches be configured at the factory for this built in function to work.

You have mail.

Best regards,

Sylvain

[grsbanks]

(03-24-2017 09:06 AM)Geoff Quickfall Wrote:  Can one erase the EPROMs?

The clue is in the name :o)

EPROM = Erasable Programmable Read Only Memory...

https://en.wikipedia.org/wiki/EPROM

[Geoff Quickfall]

Sorry, poorly written question. I was wondering here if there was a set up code in one of the 4K blocks that should not be erased.

Fir example, I cannot test with the xromtest function so I am assuming these were erased then reloaded with the Dave assembler one in upper and one in lower.

Sylvain,

Thanks for the email, awkward using TOS version. I have an eprom eraser but thanks for your offer.

So I start reading. I am assuming the system is working as the two loaded ROMs are recognized and functional.

[Didier Lachieze]

(03-24-2017 04:03 PM)Geoff Quickfall Wrote:  Sorry, poorly written question. I was wondering here if there was a set up code in one of the 4K blocks that should not be erased.

For example, I cannot test with the xromtest function so I am assuming these were erased then reloaded with the Dave assembler one in upper and one in lower.

The “XROMTST” function was part of the test EPROM delivered with the device from factory. This has been replaced by the DAVID Assembler + Mainframe Labels EPROM set in your device. The 10 bits of each instruction word are split across the two EPROMS: the lower 8 bits in the L8 EPROM and the upper 2 bits in the U2 EPROM.

You can reprogram the EPROMs or program new EPROMs with a different content. You’ll have to split a module ROM image into two files, one for each EPROM (lower 8 and upper 2 bits), using a utility program such as HIGHLOW.EXE included in SDS-II.
But if you have already a CL it will looks like going back to stone age ...

[Geoff Quickfall]

Yes STONE age but VERY interesting. :-)

Thanks everyone, it is interesting to find old tech and Didier, I would have killed for one of these in 1980!

Cheers, Geoff