Search found 6850 matches

by hoglet
Thu Feb 08, 2018 12:01 am
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 134
Views: 6026

Re: Open Source Logic Analyzer Experiments

I thought hoglet's 6502 decoder started as a plugin and migrated to stand-alone. Could it migrate back again? Possibly, but I wouldn't want to do that, for several reasons: - The C version is at least 100x faster than the python version. - PulseView tries to hold everything in RAM, which rapidly bl...
by hoglet
Wed Feb 07, 2018 9:04 am
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 134
Views: 6026

Re: Open Source Logic Analyzer Experiments

tricky wrote:I think I get you, when not powered by USB?

Yes, indeed, post now corrected! :oops:
by hoglet
Wed Feb 07, 2018 9:03 am
Forum: hardware
Topic: Minimal Tube 6502decode bus snoop with FTDI USB
Replies: 30
Views: 912

Re: Minimal Tube 6502decode bus snoop with FTDI USB

I'll certainly take a board + CPLD, thanks.

Dave
by hoglet
Wed Feb 07, 2018 7:43 am
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 134
Views: 6026

Re: Open Source Logic Analyzer Experiments

marcusjambler wrote:Am I correct in thinking there's no level shifting required? [-o<

Correct, as long as the FX2 is powered up first and powered off last. (i.e. don't leave it attached to the Beeb with it NOT being powered via USB).
by hoglet
Tue Feb 06, 2018 6:53 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 134
Views: 6026

Re: Open Source Logic Analyzer Experiments

The win sigrok download link on the Hobby components page is currently down :( http://sigrok.org/jenkins/job/sigrok-cross-mingw/platform=cross-i686-w64-mingw32/lastSuccessfulBuild/artifact/pulseview-NIGHTLY-installer.exe I've done my best to put together some Windows instructions here: http://stard...
by hoglet
Tue Feb 06, 2018 4:33 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 134
Views: 6026

Re: Open Source Logic Analyzer Experiments

My FX2LP board arrived :) But I cant find drivers for it for Win 10... Is this project a Linux only deal?? A bit of hand holding from someone would help me a lot [-o< It's not intentionally Linux only, but I don't use Windows much myself, and I don't have any Windows 10 machines to play with. Also,...
by hoglet
Mon Feb 05, 2018 10:05 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 134
Views: 6026

Re: Open Source Logic Analyzer Experiments

That board should work - are you thinking of hooking it up the the Tube initially?
by hoglet
Mon Feb 05, 2018 8:43 pm
Forum: hardware
Topic: MMFS Development and Support
Replies: 732
Views: 40015

Re: MMFS Development and Support

Coeus wrote:Is this a bug?

Yes, I think it probably is.

I've just created an issue:
https://github.com/hoglet67/MMFS/issues/8

Is this causing you an issue?

Dave
by hoglet
Mon Feb 05, 2018 7:20 pm
Forum: hardware
Topic: 2 Faulty Beebs
Replies: 89
Views: 1564

Re: 2 Faulty Beebs

While you are away, order yourself a cheap FX2 logic analyzer, then you can see what the CPU is actually doing: http://hobbycomponents.com/cypress/674-hobby-components-cy7c68013a-16ch-logic-analyser For more info see this thread: http://www.stardot.org.uk/forums/viewtopic.php?p=182748#p182748 The FX...
by hoglet
Mon Feb 05, 2018 10:15 am
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1197

Re: R65C02 in a Beeb

Out of interest did you (please could you) measure how much this: a) shifts phi1/phi2 relative to the ram clock* b) shifts the databuffer enable relative to the ram clock I suspect they might be shifted by different amounts due to the CMOS part having different thresholds? * I'm not sure what to us...
by hoglet
Sun Feb 04, 2018 6:59 pm
Forum: hardware
Topic: 2 Faulty Beebs
Replies: 89
Views: 1564

Re: 2 Faulty Beebs

That would be cool, if possible Dave. OK, both these were captured with BREAK held down. The signals are the 16 address lines. IMG_1231.JPG IMG_1232.JPG About 50% of the time you get continuous activity like this, the other 50% of the time you get a static pattern. So I think it depends on what sta...
by hoglet
Sun Feb 04, 2018 6:23 pm
Forum: hardware
Topic: 2 Faulty Beebs
Replies: 89
Views: 1564

Re: 2 Faulty Beebs

In my recent bout of 6502 bus protocol analysis, I've been doing lots of captures that start with reset held down. I'm fairly sure I've seen cases of the 6502 "chattering" when reset is asserted, depending on what state the 6502 when this happens. If it's important, I could try to confirm ...
by hoglet
Sun Feb 04, 2018 6:05 pm
Forum: hardware
Topic: Minimal Tube 6502decode bus snoop with FTDI USB
Replies: 30
Views: 912

Re: Minimal Tube 6502decode bus snoop with FTDI USB

What USB chip does the FX2 use? The FTDI has a 4K FIFO send & receive. If yours has a 4K FIFO too & it stops adding when full (rather than evict oldest) then you'll get a discontinuity at the FIFO depth. It uses a Cypress FX2 chip (CY7C68013A), also known as EZ-USB: http://www.cypress.com/f...
by hoglet
Sun Feb 04, 2018 3:45 pm
Forum: hardware
Topic: Minimal Tube 6502decode bus snoop with FTDI USB
Replies: 30
Views: 912

Re: Minimal Tube 6502decode bus snoop with FTDI USB

I knocked up an adapter on veroboard to get rid of the rats nest of jumpers. It isn't sending wrong bytes, the PC is missing blocks of bytes. When capturing from the FX2 with fx2pipe, there seems to be a similar "discontinuity" about 4KB in. The only way to avoid this seems to be to power...
by hoglet
Sun Feb 04, 2018 9:27 am
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1197

Re: R65C02 in a Beeb

AlanD wrote:I had to fit a 74ALS245 to get my beeb to work with a 65C02

Interesting. There is also mention of that here, together with a slightly more involved modification.
http://www.sprow.co.uk/bbc/howto.htm#cmosupgrade

Dave
by hoglet
Sat Feb 03, 2018 11:08 pm
Forum: hardware
Topic: 2 Faulty Beebs
Replies: 89
Views: 1564

Re: 2 Faulty Beebs

If you have ever used PALASM, you would have come across the use of / for negation:
https://en.wikipedia.org/wiki/PALASM

Dave
by hoglet
Sat Feb 03, 2018 9:23 pm
Forum: hardware
Topic: Minimal Tube 6502decode bus snoop with FTDI USB
Replies: 30
Views: 912

Re: Minimal Tube 6502decode bus snoop with FTDI USB

I'm getting a few corrupt bytes but I think this is poor signal integrity because I just shoved some jumper wires into an IDE cable to give this purple board a whirl. A rats nest of jumpers on the tube doesn't work for my co-pro so I'm not surprised. Could you possibly upload a reasonably long capt...
by hoglet
Sat Feb 03, 2018 9:10 pm
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1197

Re: R65C02 in a Beeb

This was with 100pF. i don't have anything bigger. It is an improvement over my results in the previous thread, though. What does the P2, P3 or P4 on the end of the part number signify? It signifies a 2MHz, 3MHz or 4MHz speed part. I've just tried my R65C02P4, and the 47pF capacitor is not sufficie...
by hoglet
Sat Feb 03, 2018 8:35 pm
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1197

Re: R65C02 in a Beeb

Ok with your disk image it reliably fails at PC=717E. If I hit C to continue there are more failures at the same address. All together: A=01, PS=31 A=81, PS=31 A=C1, PS=71 (twice) A=81, PS=31 (again, twice this time) A=81, PS=B1 PC=717E on the stack corresponds to the jsr report_error at 717C, whic...
by hoglet
Sat Feb 03, 2018 8:29 pm
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1197

Re: R65C02 in a Beeb

Wasn't there a thread a few days back where it was mentioned that the memory address multiplexers were critical in the sense that, while officially available from more than one supplier, in practice only one supplier's part actually worked? Or am I mis-remembering. FYI, here's the DRAM data sheet: ...
by hoglet
Sat Feb 03, 2018 7:51 pm
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1197

Re: R65C02 in a Beeb

I've just measured a second Beeb with a different processor: a SY6502A. The time from CAS0 to Phi2 (Pin 39) is 109ns, so only 1ns different. So I think we can rule out any timing peculiarities with my specific Beeb. Also the RAM seems to be significantly faster than 55ns, more like 35ns in practice,...
by hoglet
Sat Feb 03, 2018 7:04 pm
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1197

Re: R65C02 in a Beeb

I tried adding a 47pF cap across pins 37 to 1 on top of the 65C02 and rather than selection of failures I was getting before I was getting one specific failure. That still looks like the same SBC related failure. Might be worth trying a 100pF cap. To avoid confusion, do try using the disc image I p...
by hoglet
Sat Feb 03, 2018 6:30 pm
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1197

Re: R65C02 in a Beeb

This is my current hypothesis as to what's happening here. I think it's to do with the setup time margin when the CPU is sampling the read data from the DRAM. First let's look at the R6502A. Here's a scope plot showing the CPU's Phi2 (pin 37) at the top and the DRAM CAS0 at the bottom: IMG_1228.JPG ...
by hoglet
Sat Feb 03, 2018 3:52 pm
Forum: programming
Topic: Kevin Edwards assembler series in Micro User
Replies: 11
Views: 1088

Re: Kevin Edwards assembler series in Micro User

thearttrooper wrote:I extracted each episode of the series and stuck them in a single PDF. If someone knows of a good place to make the PDF available, I'll upload it.

What about http://archive.org
by hoglet
Sat Feb 03, 2018 1:21 pm
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1197

Re: R65C02 in a Beeb

After some experimentation with various small capacitors, here's a bit more data. - A capacitor between pin 37 (Phi0In) and ground is most effective and this alone fixes the problem - A capacitor between pin 3 (Phi1Out) and ground made little or no difference, even going as high as 820pF Here's the ...
by hoglet
Sat Feb 03, 2018 12:21 pm
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1197

Re: R65C02 in a Beeb

I added some extra decoupling between pins 1 and 8, and that made no difference. Now, my memory is dim of this so I just lifted the lid and there are no signs of soldering to the pins on the CPU. There are however additional disc caps across IC29 and IC37 both on pin 11 to ground. IC29 pin 11 is PH...
by hoglet
Sat Feb 03, 2018 12:02 pm
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1197

Re: R65C02 in a Beeb

dp11 wrote:try tieing pin 38 directly high e.g. to pin 8.

That doesn't seem to change anything. There is a 3.3K pullup on this pin anyway, and so it's already at 4.97V.
by hoglet
Sat Feb 03, 2018 11:08 am
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1197

Re: R65C02 in a Beeb

Maybe worth adding a little more decoupling. Also might be worth looking at the clock signal . I'll check this out. I added some extra decoupling between pins 1 and 8, and that made no difference. The clock input on pin 37 looks perfect; it goes up to 3.5V, with minimal undershoot and overshoot, an...
by hoglet
Sat Feb 03, 2018 10:44 am
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1197

Re: R65C02 in a Beeb

dp11 wrote:Maybe worth adding a little more decoupling. Also might be worth looking at the clock signal .

I'll check this out.
by hoglet
Sat Feb 03, 2018 10:43 am
Forum: hardware
Topic: R65C02 in a Beeb
Replies: 51
Views: 1197

Re: R65C02 in a Beeb

That is odd. If SBC is tested first, it might be worth reversing that to see if ADC ever fails. If ADC is already tested first and never fails, that's a datapoint. It iterates through the various input values, and for each it tests ADC first and the SBC. I'm not sure at the moment whether ADC is ev...