Search found 7362 matches

by hoglet
Tue Aug 21, 2018 9:13 am
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 159
Views: 2496

Re: Z80 Protocol Decoder

Ken doesn't tell us anything about the parity circuit, it seems, other than to imply it's very straightforward: http://www.righto.com/2013/09/the-z-80-has-4-bit-alu-heres-how-it.html You can see the parity logic (a single XOR gate per slide) in this more detailed diagram of an ALU slice from Ken: h...
by hoglet
Mon Aug 20, 2018 9:29 pm
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 159
Views: 2496

Re: Z80 Protocol Decoder

So that saves having to do the XOR instruction, very nice... I'm still tearing my hair out trying to figure out the parity flag (PF) when INxR or OTxR is interrupted. This is what I have so far for INxR: if <direction is increment> then tmp = data + ((C + 1) & 0xFF) else tmp = data + ((C - 1) & 0xFF...
by hoglet
Mon Aug 20, 2018 8:42 pm
Forum: hardware
Topic: SCSI/HADFS/ADFS/Partitions
Replies: 8
Views: 108

Re: SCSI/HADFS/ADFS/Partitions

I'd not spotted this version of ADFS - is it wildly different to the v1.50.zip on mdfs.net? I'll have a go at merging any differences in. I'll maybe look at merging the MBR stuff in as an option in for the other HD types? I'm not sure how useful that will be. If you check the commit log, the earlie...
by hoglet
Mon Aug 20, 2018 5:26 pm
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 159
Views: 2496

Re: Z80 Protocol Decoder

Do post some photos of this setup.
by hoglet
Mon Aug 20, 2018 5:16 pm
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 159
Views: 2496

Re: Z80 Protocol Decoder

Hello all, I'm also very interested in any Z80 reverse engineering activities. I've just updated the wiki page with my latest findings in on the undocumented Z80 flag behaviour when block instructions are interrupted: https://github.com/hoglet67/Z80Decoder/wiki/Undocumented-Flags Tony, here's a PDF ...
by hoglet
Mon Aug 20, 2018 4:45 pm
Forum: hardware
Topic: SCSI/HADFS/ADFS/Partitions
Replies: 8
Views: 108

Re: SCSI/HADFS/ADFS/Partitions

On question 1 - afaik there is no partition support (certainly not in 8-bit ADFS). (Probably a bit off-topic, as you are talking about the SCSI driver) FYI, a couple of years ago I did add MBR partition table support into the SD card build of ADFS 1.5x (called ADFS 1.57): https://github.com/hoglet6...
by hoglet
Mon Aug 20, 2018 12:43 pm
Forum: hardware
Topic: Model B Video gone fuzzy/corrupt and blurry
Replies: 34
Views: 1727

Re: Model B Video gone fuzzy/corrupt and blurry

Interesting... What mode was that screen shot in? It looks like mode 7. Did you say earlier that the memory test was passing? I imagine it would now fail - worth re-checking. 4-6 Should it be in 'c' mode between steps 4,5 & 6 ? Both are of interest. There's more potential for something going wrong i...
by hoglet
Sat Aug 18, 2018 11:02 am
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 159
Views: 2496

Re: Z80 Protocol Decoder

Thanks Dave, I can't access github though on my old but quick PC and I think a post here would do. Why is it you can't access github? The direct link to the page is: https://github.com/hoglet67/Z80Decoder/wiki/Undocumented-Flags What browser are you using? What error do you get? I'll still update t...
by hoglet
Sat Aug 18, 2018 7:19 am
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 159
Views: 2496

Re: Z80 Protocol Decoder

How conditional instructions affect WZ is perhaps slightly clearer than the Russian document on this webpage: https://problemkaputt.de/zxdocs.htm#z80cpuspecifications Thanks again Tony. Those all match my currently understanding, apart from the first one: A*100h LD (xx),A ;xx=BC,DE,nn The above is ...
by hoglet
Fri Aug 17, 2018 2:03 pm
Forum: hardware
Topic: Model B Video gone fuzzy/corrupt and blurry
Replies: 34
Views: 1727

Re: Model B Video gone fuzzy/corrupt and blurry

Piggy backing has no effect. Piggy backing works in quite a narrow set of failure cases, i.e. specifically when an output has gone open circuit, or is very weak. As the ICE-T can read/write video memory, we known that is not the case here. IC14 is a very critical component in a Model B, as it isola...
by hoglet
Fri Aug 17, 2018 9:11 am
Forum: hardware
Topic: Model B Video gone fuzzy/corrupt and blurry
Replies: 34
Views: 1727

Re: Model B Video gone fuzzy/corrupt and blurry

It might be worth doing a few more tests with ICE-T on the video memory. I would try the following: 1. <return> on the ICE-T to enter command mode, the do RD 0355 to establish the current screen mode, then C to continue (for the rest of these thoughts, I'll assume you know how to use the ICE-T comma...
by hoglet
Thu Aug 16, 2018 11:04 pm
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 159
Views: 2496

Re: Z80 Protocol Decoder

GAL is finished and NMI was simple to include. The Special Reset can occur during the first or second opcode fetch of an instruction (if the latter exists) and after a HALT (which is the most interesting case). Nice one. Are you planning to prototype this then? I've made a little more progress with...
by hoglet
Thu Aug 16, 2018 2:54 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 201
Views: 10950

Re: Open Source Logic Analyzer Experiments

Any "prediction fail" from the logic analyzer decoder (once everything is in-sync and all register are know) is an indication of: a) A bug in the decoder b) A data sampling error (in my experience on the Beeb vary rare indeed) c) Some kind of a hardware issue (e.g. bus contention) that's worth inves...
by hoglet
Thu Aug 16, 2018 1:12 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 201
Views: 10950

Re: Open Source Logic Analyzer Experiments

So I am at a loss to explain capture data5 I agree, given what you have said, it's hard to imagine how data5 could look like this. The value read from &FE4E was &88 - it should have been either: - &80 after a power up break - &D2 after a normal break (T1 interrupt, CB1 interrupt, CA1 interrupt) I w...
by hoglet
Thu Aug 16, 2018 10:09 am
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 201
Views: 10950

Re: Open Source Logic Analyzer Experiments

Hmm. By power up break you mean from a switch on? That is what I did. I Set up fx2pipe to captue first and then powered on.I dont think I could have sent the wrong trace as the only non powerup breaks I have traced were live ones and not saved those to a file as piped stright into decode. Or I have...
by hoglet
Wed Aug 15, 2018 5:29 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 201
Views: 10950

Re: Open Source Logic Analyzer Experiments

I did a number of live runs but it never hung in the same area of code. So probably taking trace wont help me, unless there is an obvious difference/error. But was worth a try and certianly I know it all now works. There's nothing especially suspicious in the trace. For example, there were no memor...
by hoglet
Wed Aug 15, 2018 12:25 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 201
Views: 10950

Re: Open Source Logic Analyzer Experiments

Elminster wrote:
Wed Aug 15, 2018 12:12 pm
Yep. How big do you want the fx2pipe set to?
Start with 12M samples, which should be about 6 seconds,

Dave
by hoglet
Wed Aug 15, 2018 11:42 am
Forum: hardware
Topic: Raspberry Pi B+ compatible GPIO Extender 40-way Ribbon Cable Female-Male
Replies: 27
Views: 471

Re: Raspberry Pi B+ compatible GPIO Extender 40-way Ribbon Cable Female-Male

The pi is working fine off the TUBE and can't understand why i can't use an extended cable even though the 30cm and 50cm cable works on my other bbc's? even Mark at RetroClinic is baffled. To be fair, Mark didn't develop PiTubeDirect, and only very recently started selling them. Are your other beeb...
by hoglet
Wed Aug 15, 2018 11:38 am
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 201
Views: 10950

Re: Open Source Logic Analyzer Experiments

Great, the tool is now working....

Can you upload another data.bin trace file?

I have had some success in the past at using diiff to compare to a known-good reference trace.
by hoglet
Wed Aug 15, 2018 11:36 am
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 159
Views: 2496

Re: Z80 Protocol Decoder

May I suggest placing WZ directly after SP and before IR? That is the actual order on the die from right to left. Also using the official names IFF1/2 instead of IF1/2, perhaps showing the two as a 2-bit IFF=xx for brevity. Done. CPxR would be simpler to do before INxR/OTxR which are very strange, ...
by hoglet
Wed Aug 15, 2018 5:58 am
Forum: hardware
Topic: Raspberry Pi B+ compatible GPIO Extender 40-way Ribbon Cable Female-Male
Replies: 27
Views: 471

Re: Raspberry Pi B+ compatible GPIO Extender 40-way Ribbon Cable Female-Male

Back2skooldaze wrote:
Tue Aug 14, 2018 9:48 pm
I still can't get the pi to work on the extended cable? If the pins where tarnished then the pi would not work when plugged in directly to the TUBE connector?
Is this now with a 30cm cable?
by hoglet
Wed Aug 15, 2018 5:40 am
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 159
Views: 2496

Re: Z80 Protocol Decoder

Could you add WZ=xxxx to your log after SP, for PUSH AF if nothing else? It'll be needed when using my new device! That's already there (with the -s2 option) I just didn't include it in this example. The extra stuff looks like: IR=???? IF1=? IF2=? IM=? WZ=???? If anyone reading this is confused abo...
by hoglet
Wed Aug 15, 2018 5:36 am
Forum: acorn atom
Topic: Atom 2k18 ?
Replies: 41
Views: 1277

Re: Atom 2k18 ?

I tried to add my cpld files to the Atom Godil project in ISE but it did not recognise these files. Even when I force an error ( keyword: entyty ) there was no error. How can I add my two sources? How exactly did you add the sources? As well as placing them in the src directory, you need to tell th...
by hoglet
Tue Aug 14, 2018 9:39 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 201
Views: 10950

Re: Open Source Logic Analyzer Experiments

Another possibility with a machine like this is to blind type *FX 2,2 and *FX 3,1 then use the serial port to run some tests.
by hoglet
Tue Aug 14, 2018 9:14 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 201
Views: 10950

Re: Open Source Logic Analyzer Experiments

Edit2: As you can see from the thread https://stardot.org.uk/forums/viewtopic.php?f=3&t=9438 I dont have much visual clues to go on. I feel like I am making progress, even f only in understand what tools to use and how to use them. Yes, but from that thread you say: Restarted it and goes through po...
by hoglet
Tue Aug 14, 2018 8:47 pm
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 159
Views: 2496

Re: Z80 Protocol Decoder

The flag info in "The Undocumented Z80 Documented" for the block repeat instructions only applies when the counter = 1. Yes, I tend to agree. Take OTIR for example with B=3. This will look like: - OUTI (16 cycles) - decrement PC by 2 (5 cycles) - check for interrupt - OUTI (16 cycles) - decrement P...
by hoglet
Tue Aug 14, 2018 8:28 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 201
Views: 10950

Re: Open Source Logic Analyzer Experiments

This very is nearly working... it's just bits 4 and 2 not making proper contact somewhere. Definitely start by cleaning the tube connector, either with something abrasive, or by plugging/unplugging the cable about 20 times. Then it will get really interesting and you'll see the value of this over a ...
by hoglet
Tue Aug 14, 2018 8:21 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 201
Views: 10950

Re: Open Source Logic Analyzer Experiments

I think either the Myelin FX board is faulty, or the tube connector is dirty and not making a good connection.
by hoglet
Tue Aug 14, 2018 8:18 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 201
Views: 10950

Re: Open Source Logic Analyzer Experiments

This is interesting.... Here's my "reference trace" for a Beeb booting: 0 68 1 1 1 1 68 0 1 1 2 01 0 1 1 3 ff 0 1 1 4 01 0 1 1 5 cd 0 1 1 6 d9 0 1 1 ???? : : RESET !! 0 a9 1 1 1 1 40 0 1 1 D9CD : A9 40 : LDA #40 0 8d 1 1 1 1 00 0 1 1 2 0d 0 1 1 3 40 0 0 1 D9CF : 8D 00 0D : STA 0D00 0 78 1 1 1 1 d8 0...
by hoglet
Tue Aug 14, 2018 7:50 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 201
Views: 10950

Re: Open Source Logic Analyzer Experiments

Do you have a working Model B you can capture a reset trace off first, just to check the tools are working properly. Otherwise you might be chasing ghosts.... Oh, and don't use "live mode" for now, too many variables and if the system struggles to keep up the USB link will drop data and you'll just ...