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ZjoyKiLer wrote: ↑Sat May 18, 2024 5:45 pm Fantastic!! but hey, I'm not Sergey, but the owner of the repo that is responding to Sergey.

Ah, sorry about that, now fixed. So you are Redcode/Manuel then?

Great! Thank you very much :) I've discovered a couple of things. 1. I made an error when transcribing my Z80 Decoder code onto the Undocumented Flags wiki page, for the ST CMOS CPU. XF = A.3 if <previous instruction modified the flags> then YF = A.5 else YF = YF | A.5 endif Should in fact be: XF =...

That locks the RAM again. If the Sideways RAM bank locks every time you press break, then it's not going to work well. The Sideways RAM version of MMFS needs the RAM to be writeable all the time. I would recommend fitting a 62256 RAM in ROM 4, as there is no locking on this slot in the AP6, so the ...

ZjoyKiLer wrote: ↑Wed May 15, 2024 11:13 pm And please, take a look at this test: https://github.com/redcode/Z80_XCF_Flavor.

I'll take a look and do some investigation. I might try to port that test to the Acorn Z80 Second Processor, which is where I have the SGS/ST Z80.

BeebMaster wrote: ↑Wed May 15, 2024 9:04 pm It seems the lost channels are part of "PSB3 multiplex" whatever that means, but which RF channel that transmits on (Winter Hill transmitter) seems to be classified information.

PSB3 is on Channel 35:
https://ukfree.tv/transmitters/tv/Winter_Hill

Dave

It comes from my DFSfix modules, ported in turn from code I added to EDOS . DFS 2.29 has fast OSGBPB routines at &9C8B but I haven't yet compared notes. Would you mind if we included that code in MMFS? It actually makes a very significant difference, even more so with an SDCard than than with f...

regregex wrote: ↑Tue May 14, 2024 7:08 pm I've added a patch to DFS 2.24a (include -D _BUGFIX while assembling) and it holds up to testing.

Thanks for the link to your excellent disassembly.

I'm very interested in the origin of the _FASTGB code? Is this back ported from a latest version of DFS (which version?) or is it your own?

Dave

I made a very basic start today but I can't get at the link above - did you keep a copy of it anywhere. I'm particularly interested in the changes between 2.44 and 2.45 at the moment... That link is working for me... It's also on archive.org: https://web.archive.org/web/20231210074615/http://regreg...

KenLowe wrote: ↑Tue May 14, 2024 12:22 am Was looking for some thoughts before I start randomly pulling ICs...

Logic analyzer trace of the MOS executing a power up reset?

Remklep wrote: ↑Mon May 13, 2024 1:26 pm As an example, the game Zalaga on page 65 of the Sd card.

Many games are not compatible with the Master.

It would be helpful to be very specific about the games that are failing.

Zalaga, for example, uses undocumented 6502 opcodes that are not present in the Master's 65C12 processor.

Dave

Can someone test the gameplay? OK, I've figured it out. The board is fixed, and the colours/shape (of which there are eight) are part of the board, You and the computer both have four "pieces" indicated by the highlighted boxes. Your pieces all start at the bottom. The computer's pieces a...

I have also fixed some glitches with the ReCo6502 (at least as emulated in b-em), which would fail to run games built with turbo support and would report nonsense times for the benchmark because Acorn Ozmoo's code relied on 6502-only behaviour (the ReCo6502 uses a 65816). FYI, on a real 65C816 the ...

I typed-in Footprint but I can't figure out how the game works so can't test it .... Thanks very much for typing this in. It looks like a nice game. Can someone test the gameplay? I've given it a try, and I'm also a bit confused. The article says: "must be moved directly in front of an opponen...

I wrote an Atom RAM test with similar goals: https://stardot.org.uk/forums/viewtopic.php?t=24634 It makes heavy use of macros, indexed addressing and doesn't need any stack/RAM to run: https://www.youtube.com/watch?v=ohPfL5uom7g For additional state, it uses: - the VIA ACR to track the three test ca...

John Kortink also has a nice solution to the reset problem using a DS1818: (twitter)

Another reason why it would be a major task to get the HCR to handle these chips.... The hardware is certainly able to handle the CS2 input, as pin 18 is under complete software control. I'm less sure it can generate the right shaped programming pulse on nCS1/VPP: Capture.PNG What's unusual here is...

I was puzzled as to how the RAM could be a factor in this startup problem, but as you more experienced guys all seem to think so, I will certainly investigate further. (Plus, I think I figured out the "how" now, too!) If the RAM in IC51/52 is unreliable, then the 6502 stack will be affect...

When I try to manually calibrate the RGB2HDMI I am unable to find any setting where the image is stable, despite seeing a stable image when running an auto-calibration - do I have access to exactly the same parameters from the sampling menu, or are other things at play? That clock doesn't look too ...

The scope looks very nasty, storing a long sequence I can see the widths varying but by much more than another Beeb I have to hand. If you scope the 6MHz clock (pin 19 of the SAA5050), set the horizontal timebase to 50ns/division and then adjust hold-off you should get a stable trigger showing thre...

The RGB2HDMI won't give me a stable MODE7 on these new PCBs. I noticed an issue in the original BOM for the board where C48 is specified as 220pF but the Service Manual gives it as 270pF. I'll pop mine out and change it later, to overcome this, I replaced IC37 with a 74F04 and the problem went away...

I understand your remarks about the pulse length. What I am not sure about (I've tried to decipher the ROM code, but it's very complex) is if these 24 pin devices get Vcc raised during programming. The 2732 data sheet says Vcc=5V, so I suspect they don't. The 27128 (for example) gets "VCC = 6V...

Thanks - however I don't think it's worthwhile going out of your way to do - unless there is a pressing needs from e.g. others for this as ultimately I want to turn the project into a "real" (virtual/emulated) CPU - unless all those other emulated CPUs also need it, or already have a mean...

im just having a look through the source code here https://github.com/hoglet67/PiTubeClient/blob/master/bare-metal/copro-65tubeasm.S That's the wrong place. You need to be looking here: https://github.com/hoglet67/PiTubeDirect All of the "6502" Co Processors in PiTubeDirect implement the ...

I will investigate this next time I get to work on it. I'll get the logic probe on those lines. I notice D2 has a 4k7 pull down at R40: am I right thinking any fault would need to actively drive D2 high to produce a KIL opcode? Yes, but it would have to drive D1 high, not D2 (that also has a 4K7 pu...

XOS_CLI? Well that's a new one on me. Now I have to find the code for that in PiTube and emulate it. And this doesn't exist. I guess this is some sort of RISCOS thing. The X prefix to SWI calls on RISC OS just (I think) means setting bit 17 of the SWI number. Normally an error during an SWI call wi...

Has anyone any ideas what might be going on? I don't think the 6502 has a Halt mechanism other than RDY, does it? Is there any instruction that could cause this behaviour? There are certain undocumented 6502 opcodes (called KIL) that will halt the processor: https://www.oxyron.de/html/opcodes02.htm...

Halifask wrote: ↑Mon May 06, 2024 4:19 pm Could you let me have the details for payment please.

PM sent...

Halifask wrote: ↑Mon May 06, 2024 1:57 pm When you say "not cheap" at a guess (won't hold you to it) how much?

I would guess £70(ish), but that will depend on whether you have to buy absolutely everything.

DAVE

Halifask wrote: ↑Mon May 06, 2024 11:50 am Just came across this topic and I'm wondering if I should build one, do you still have PCBs for it?

I have one PCB left (for £15 inc UK postage).

PM me if you are interested.

It's not a cheap project to build though....

Dave

From the data sheet (attached) they require "VCC = 6.25 V ± 0.25 V, VPP = 12.75 ± 0.25 V" and "tPW Program Pulse Width 100 to 200 μs" to program them. I wonder if the 2732 settings (having manually selected the 12.5V programming voltage) are just not right. I also include the da...