Gah...

Well, I've managed to identify the waiting for key press loop, and I'm working on the Signature routine.

It appears to start at 932Bh. When I trigger the LA to start when a READ returns a EB and then a BD (the two bytes I'm using in a very short signature) I get the following code (just a bit of the code)

STATE   PC   DISASSEMBLY   BUS ACTIVITY   
  
-0017 9309 IN   A,(C0)       C0>F8                                             
-0014 930B AND  02                                                             
-0012 930D JR   Z,932B-$                                                       
-0010 932B LD   L,(IX+04)  FF70>86     <- I/O port start                                        
-0006 932E LD   H,(IX+05)  FF71>F6                                             
-0002 9331 IN   A,(C2)       C2>BD     <- Here is the Data byte - BD                                        
00001 9333 LD   (HL),A     F686<BD                                             
00003 9334 LD   A,19                                                           
00005 9336 OUT  (C0),A       C0<19                                             
00008 9338 LD   B,02                                                           
00010 933A LD   (IX+F8),F8 FF64<00                                             
00015 933E LD   (IX+F9),F9 FF65<00                                             
00020 9342 IN   A,(C0)       C0>19                                             
00023 9344 AND  02            

I know next to nothing of Z80 op codes though....if anyone wants to work with me on this I can pump out the disassembly if they can figure it out from there...

I wish my ML4100 had the extra RAM to enable it to store 2000  steps instead of  1000. Does anyone have an Arium ML4100 with the optional Setup/Data Memory Board and be willing to send me the Eprom code? I'm putting the updated Arium ROMs (including some CPU Disassembly ROMs and RS232 Disassembly ROM, all zipped) on the archive in a minute or two...

John :-#)#