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After a week spending evenings trying to debug this, finally some success!



OS-9 Level 1 running on the MECB 6809 and all its multitasking goodness

In the end, what wasted all of my time was not realising that the 6850 port address was defined once in the configuration file for the system but also a second definition tucked away in one of the makefiles!

epaell wrote: ↑Sat Aug 10, 2024 5:32 am After a week spending evenings trying to debug this, finally some success!

OS-9 Level 1 running on the MECB 6809 and all its multitasking goodness

In the end, what wasted all of my time was not realising that the 6850 port address was defined once in the configuration file for the system but also a second definition tucked away in one of the makefiles!

Wow! This is pretty awesome to hear (understatement of the year!).

While I'm still buried in KiCAD PCB layout, you're busy doing some amazing software development magic! I'd only just dreamed of diving into that challenge at some stage, but haven't even looked at any code yet.

It seems to be a very nice OS given the 64KB memory limitations of the 6809. In my travels debugging my earlier problems I learned more than I anticipated about OS-9 and its innards - it's quite nicely designed. I love the way things can be in ROM or memory - it doesn't really care and just finds the modules that are available regardless of where in memory they are. The memory doesn't even have to be continuous - it'll make use of little chunks wherever they may be e.g. I have my I/O between $E000-$E0FF and the ROM in $F000-$FFFF and it quite happily squeezes modules in the bit in between the two ($E100-$EFFF). Sadly, even with this nice ability, it wasn't able to scrape up enough memory to run the C compiler (though it is unclear to me how much more it needed and whether moving the I/O up so that it is just before the ROM to enable a larger contiguous chunk would help - perhaps an experiment for another day).

Looks like that maybe did the trick although now I'm wondering if I could've got it working without that change. After a bit of investigating (because I was still getting a out of memory error despite having a pretty decent amount of contiguous memory available) I noticed that the NitrOS9 version of the compiler (cc1) creates a compile script which it then executes to perform all of the preparation, passes, compiling, assembling and linking but it would still get OOM during the first pass. I noted at this point the initial compiler module (cc1) was still in memory - if I unlinked it (remove from memory) then the script would run fine.

It's still not clear to me whether I have to use the NitrOS9 version of the C-compiler (which seems to be a "TANDY" version of the compiler) or whether it is possible to use the original OS-9 version. For that matter, I'm not sure if I can just use any OS-9 software out of the box (or if I need to specifically use the nitrOS9 versions). Perhaps something else to try when I get a chance.

Editor wrote: ↑Fri Aug 09, 2024 1:38 am

lenzjo wrote: ↑Thu Aug 08, 2024 8:13 pm Thx Greg, that's a nice series - just watched the first vid. That F256K system is interesting if not a bit expensive, but I did notice the cpu addon a 6809/6803 with the pin-out of a 65c02.

Yes, I've been following the F256K evolution for some time. Mainly because of the FNX6809 CPU option. Quite expensive though, and more of an interesting system for someone who just wants a pre-built retro system to develop software on (as opposed to overall 8-bit hardware & software experimentation).

The FNX6809 CPU is indeed a cycle accurate implementation of the 6809, with a 65C02 pin-out. Implemented as a FPGA core on a 40-pin DIL carrier board. The only thing is that it's really only useful for the F256K, as it's 3.3V powered! So you can't just drop it into an existing 65C02 system (5V powered), DIL socket!

A pity, as if it were 5V powered it could (in theory), open up experimentation like dropping it into a C64. Of course, you'd need to re-write all the code to drive the C64 hardware with a 6809, but I could see this could be a fun project for the C64 hardware (or other existing 6502 systems).

MECB benefitted from that steep price cliff of the F256K - I'd like to get into the Foenix one day, but got into this MECB project for its flexibility, modularity and price point for players, tinkerers and maybe ecosystem contributors like myself...

bugeyedcreepy wrote: ↑Sat Aug 17, 2024 5:07 am MECB benefitted from that steep price cliff of the F256K - I'd like to get into the Foenix one day, but got into this MECB project for its flexibility, modularity and price point for players, tinkerers and maybe ecosystem contributors like myself...

Yes, I've been following the F256K for a while now. Although, I don't see it as an alternative to MECB. They really are two different beasts with different purposes. The only thing they really have in common is they're both retro 8-bit.

MECB is really targeted / optimised for experimenting with original 8-bit hardware devices (CPUs and Peripheral chips), whereas the F256K is a complete system more applicable to retro system application software development.

I'd like to explore the F256K for a project like developing a game for a new retro platform, but at the moment all of my available time is consumed by my existing retro experimentation projects.

epaell wrote: ↑Sat Aug 10, 2024 5:32 am OS-9 Level 1 running on the MECB 6809 and all its multitasking goodness

I just realised I didn't make enough of a hoolabuloo over this, This is an Awesome achievement!! I was hoping an OS9 of some flavour would make its way over here - still not gutsy enough to bring my own cf card reader into play yet - just not confident I'd be able to get it going.... -_-

I've managed to get it to run with multi-user and multi-tasking now (after adding another serial card) ... I'm just waiting for another PIA to arrive in the mail so I can demonstrate it better

epaell wrote: ↑Thu Aug 29, 2024 11:16 am I've managed to get it to run with multi-user and multi-tasking now (after adding another serial card) ... I'm just waiting for another PIA to arrive in the mail so I can demonstrate it better

Wow! You have been busy. Can't wait to see a demonstration.

Multi-user / Multi-tasking also sounds like a good candidate to take advantage of some over-clocking.

epaell wrote: ↑Thu Aug 29, 2024 11:16 am I've managed to get it to run with multi-user and multi-tasking now (after adding another serial card) ... I'm just waiting for another PIA to arrive in the mail so I can demonstrate it better

Ooh! Yes Please!