HP41-CL - Module behaves differently than on 41CX

[PeterP]

(12-30-2017 12:44 AM)hth Wrote:  

(12-29-2017 10:28 PM)PeterP Wrote:  I then tried to create a pristine 41CX:

• Memory Lost
• MMUDIS
• MMUCLR
• MMUEN
  

This removes access to the YFNZ/YFNX of course but should give me a plain old 41CX. However, upon plugging in the COGO41, the calculator hangs again.

Now I'm stumped and can't think of what else to try.

Question: How is this possible? Any suggestions on what else to try?

It is possible if it uses page 7. Move the YFN* module away from page 7 before you enable the MMU.

Håkan

Yes, I tried that. The above sequence actually creates a CX without any YFNZ/X, so only pages 1,2,3,5 are used. Still hangs.

With regards to it predating the CX - it works in a standard CX just fine, which would seem to invalidate that hypothesis also.

Theoretically the above procedure should create a 41CL which is identical to a standard CX. However, the COGO41 works on a standard CX, but not a CL prepared in this manner. So there is for certain some difference. Question is - what difference? And why does said difference make the module hang? Could there be an opcode used in the COGO41 for the 16k EPROM(?) hardware it runs on which is (mis)interpreted by the 41CL? If so, which op-codes does the 41CL use (so that I could search on my normal CX using the hepax module in the listing of the COGO41, which btw looks to be mostly FOCAL code. The plot thickens...