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Re: [N8VEM-S100:4168] Multiple Rom Monitors and a conflict

Thanks for the tips -
I am not using the S100 CPU board, I have a Cromemco ZPU.

Master Z80 ORG = F000 (Currently ROM_HIGH_PAGE=FALSE)

Since either of the Rom monitors work perfect in the system by themselves, I think the problem is this high memory probe because that is where both stop. 
I will assign ROM_HIGH_PAGE=TRUE to get the XMODEM functionality and test from there.

The tip about forcing the stack to C000 is a good one, so I will try that is well.




On Tuesday, June 17, 2014 6:07:49 AM UTC-4, monahanz wrote:
OK Thomas, more info helps!

First I'm assuming then you are not using the N8VEM/S100Comnputers Z80 board.  Right?
If not, be sure the Upper / Lower page selection code in the monitor is set for either the XMODEM or ZFDC code (ROM_HIGH_PAGE  equate) since your board will not be able to flip the ROM pages.
Probably best to start with ROM_HIGH_PAGE = TRUE that way you can use XMODEM to download versions of the MYIDEROM into various locations of RAM for debugging.
If you get a functional Monitor running you can then download another version of that Monitor (reassembled of course) anywhere in RAM and do the same for the IDE code.  This way you are not burning ROMS until you figure everything out.

I assume you have the ORG for the IDE code set to E000H, right?

The monitor (near the start, at AHEAD: & MEMSZ1)  figures out the top of RAM that is available to it.  If you have the other ROM at E000H at the same time it will continue to probe lower (assuming no RAM between the two ROMS), so I don't think that's your problem.     To be on the safe side and to test  try forcing the stack at C000H.
LD        HL, 0C000H
LD        SP,HL

As a general principal you should approach a problem like this by outputting a character to the screen at the start of each ROM, that tells you a lot, then move it within the code.  If you have a front panel or our SMB of course you can set hardware breakpoints, single step etc.  Sorry don't know your setup.
You can always fall back on a ROM filled with 76H's (HALT) to check your board addressing BTW,


-----Original Message-----
From: n8ve...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of Thomas Owen
Sent: Friday, June 13, 2014 4:32 PM
To: n8ve...@googlegroups.com
Subject: RE: [N8VEM-S100:4168] Multiple Rom Monitors and a conflict

Hello Everyone,
I should have been a little more clear with my statements...

I install the rom, either one, in my Ram17 board by simply removing ram chips.  So, either one will work installed by itself in the system.
I can access all functions of both roms just fine.

It is when they are both installed in the system together, one at e000 (myiderom) and the other at F000 (masterz80) that neither will work.
I start the system, reset, and try to run from either start address and the system just hangs.

I think John is on to the problem as i believe they both are trying to use space occupied by the other rom, thinking it is ram.
What I need to do is set the top of ram below the rom at E000 (I think!) within each rom.

Ram 0 - EFFF Rom at F000.  This works fine.

Ram 0 - DFFF, rom at E000. This works fine.

Masterzz80 and myiderom together in system:
Ram 0 - DFFF, Myiderom at E000 to EFFF, Masterz80 at F000 to,FFFF.  System simply hangs trying to launch either rom.

Thanks again,

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