Hi everyone In case this is new to anyone I'm posting links to Dave Dunfields Software. Much of it is now free to download. In particular I have just found the source for a 6809 monitor which needs no ram of any kind to operate, just ROM and UART, maybe I can get my old system working again with thi...

RetroChallenge should give MECB lots of publicity, great.
I was surprised to see so few entries, when does submissions close?

Hi All, If you haven't seen it then have a look at this github site for 6809 projects. I have most of this stuff running on my FPGA 6809s, hopefully the porting to MECB when the time comes won't be too difficult ...
https://github.com/nealcrook/multicomp6809
hth David.

It turns out that adding a simple single line disassemble to Assist09 after a trace instruction isn't very difficult at all. The formatting could be improved maybe by arranging the output to a single line. >R PC-ECAF A-00 B-BF X-FFFF Y-BFB2 U-BF45 S-BF35 CC-D4 DP-BF PC-EC74 >T 8 PC-EC77 A-81 B-BF X-...

Hello everyone, Today I got nowhere trying to get NMI from the PTM o1 output working properly, however... Instead I have reconfigured mame to give NMI interrupt from its irq pin and reconfigured Assist09 to enable interrupts on the PMT when single stepping. Much to my surprise this kind of works in ...

After a lot of head-scratching (mainly me fighting with the 6840 documentation, fighting with how to do things with a 6502, and then fighting with SMON) I finally got something that works: Greetings Emil, I took your PTM code and massaged it to work with Assis09 in MAIM. I actually built it into th...

Would something like this work for the NMI (in addition to the original IRQ line - I think that is needed for normal timer operation): m_ptm->o1_callback().set_inputline("maincpu", INPUT_LINE_NMI); I'm not sure if it would compile - I can't check right at this moment and I'm not very fami...

Ah, I should have looked at the schematic more carefully, I'd assumed nmi was being driven by the interrupt pin. Anyway this explains why I've not seen an interrupt in mame. Now I need to see how to patch the output to the nmi input. I've seen some weirdness in some of the mame devices. I'll look ag...

Looking at the schematic of the mecb motorola i/o board I see that the NMI signal from the 6840 PTM is inverted. I see no accommodation for this in the MAME implementation. THhs is perhaps causing the problem I have getting the Assis09 single stepping to work. No other device interrupts need inverti...

In my previous post I mentioned a new problem, it seems that the old version has the same problem too. I also realised that I had not used the same test commands. I've just re-tested my change and can verify that D FF00 FF does not loop forever, the other odd behaviour is the same or similar in both...