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Old 25th Jul 2023, 4:57 pm   #321
SiriusHardware
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Default Re: Commodore PET 4032/8050/3022

OK, I'll let you get the hang of that. Practice capturing one-shot events until you are reasonably familiar with how to do it. Once you feel you are, we'll do one-off captures from other signals of the CRTC and also the ones on the other large ICs.

This is possibly the first time we have managed to observe the Tynetec board trying to initialise the CRTC, if so, this is progress of a sort.
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Old 25th Jul 2023, 5:17 pm   #322
ScottishColin
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Default Re: Commodore PET 4032/8050/3022

Is it possible to identify a test that we know will work with two other ICs/pins?

I'm struggling a little with the interface and it'll be easier for me if I can have a known working test to help me.

Thanks.

Colin.
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Old 25th Jul 2023, 5:48 pm   #323
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Default Re: Commodore PET 4032/8050/3022

Well, as I mentioned, try using the rising edge of RESET on the CPU to trigger channel 1 (as you have been doing) and use channel 2 to look at what happens on some known 'busy' signals such as the address lines A0, A1, A2 immediately after reset.

I couldn't see from reading the manual how to re-arm the SINGLE trigger, have you figured out how to do that yet? It describes how to set up to capture an event using SINGLE sweep mode, but doesn't explain how to re-arm it to wait for the next trigger event. (Page 48-49)

https://www.sigmaelectronica.net/man...2BE_Manual.pdf
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Old 25th Jul 2023, 6:15 pm   #324
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Default Re: Commodore PET 4032/8050/3022

Hmm, there is someone on Github here describing an issue of SINGLE mode not working properly for him using the OpenHantek software.

While I realise you are not using that software I wonder if there is some issue in the 6022 firmware which prevents the SINGLE mode from working with any software, be it third party software or the 'official' software.

https://github.com/OpenHantek/OpenHantek6022/issues/308

After the trace has 'fired' once and captured a frozen screen worth of activity you should be able to re-arm the SINGLE sweep mode by either clicking on a START button or pressing 'S' on the PC keyboard, but again, that information relates to the OpenHantek Software. I don't know what the equivalent actions on the official software would be but I would have thought that the open software would closely follow the interface conventions used by the official software.
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Old 25th Jul 2023, 7:17 pm   #325
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Default Re: Commodore PET 4032/8050/3022

Looks like it was fixed in 3.3.0.1 and the latest release is 3.3.2.2.

I had not thought of OpenHantek or strictly speaking OpenHantek6022 as the former is unsupported and has no maintenance for years.

I may well give that a try later on as the interface for this task using the official software is not obvious (at least to me).

Colin.


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Originally Posted by SiriusHardware View Post
Hmm, there is someone on Github here describing an issue of SINGLE mode not working properly for him using the OpenHantek software.

While I realise you are not using that software I wonder if there is some issue in the 6022 firmware which prevents the SINGLE mode from working with any software, be it third party software or the 'official' software.

https://github.com/OpenHantek/OpenHantek6022/issues/308

After the trace has 'fired' once and captured a frozen screen worth of activity you should be able to re-arm the SINGLE sweep mode by either clicking on a START button or pressing 'S' on the PC keyboard, but again, that information relates to the OpenHantek Software. I don't know what the equivalent actions on the official software would be but I would have thought that the open software would closely follow the interface conventions used by the official software.
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Old 25th Jul 2023, 7:18 pm   #326
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Default Re: Commodore PET 4032/8050/3022

I sent an email today to tfw8b which is where I got the Tynemouth board regarding CTRC support and support for the built-in testing software and got this quic repsonse:

"Yes, the 4032 and 8032 ROMs are the versions for CRTC based PETs (although they also run on older PETs.

The simple PET tester ROM does not initialise the CRTC, so you need to first switch to the 4032 BASIC 4 ROM set, boot up, then switch the ROM to the PET tester ROM and hit the reset button. The PET tester knows nothing of the CRTC, so it remains set how it was previously and the screen is displayed as normal.

If you cycle the power, you need to boot to the 4032 ROM again to reinitialise the CRTC."

Colin.
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Old 25th Jul 2023, 8:13 pm   #327
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Default Re: Commodore PET 4032/8050/3022

That's very useful information for the future: At the moment (as far as I knew) these recent experiments with the Tynemouth board have so far been carried out with the Tynemouth board 'being' the 5-ROM set and system memory, and not with the minitester code. Can you confirm this is still the case?

As far as I know the CRTC gets told what to do under firmware instruction shortly after the CPU comes out of reset and then after that it just keeps running, generating the Hdrive and Vdrive signals at the correct frequencies to activate the monitor, among other things, much as the dedicated hardware on your other PET does, although in that machine the video hardware already knows what it is supposed to do and doesn't need to be told.

I'm surprised that (according to the information you've received) the CRTC will continue executing its instructed operating mode even following a soft reset where the main RESET line on all the large ICs gets taken low then high again. I would have expected that a RESET to the CRTC would clear its programmed settings to the chip's defaults so that is a bit of a surprise.

Regarding the interface, in all those icons along the top edge of the software interface is one of them a 'RUN' button? I would expect that in SINGLE sweep mode it will do one sweep, and then go into STOP mode. If that's so, you should be able to 'arm' it ready for another single capture by hitting RUN. It should then sit waiting for another valid trigger event, ie, the next time there is a rising edge on RESET.

Have to dive out for a few hours again but I'll just say that Daver2's code always initialises the CRTC every time it is started, so if you put that in and do a single capture, channel 1 triggered by rising edge of RESET, channel 2 on UE13 pin 12, see if you always see some CRTC chip select pulses there immediately after reset. As mentioned earlier the only problem with Daver2's code is that it requires a working UD6 to send the CPU into the code in UD7.

The Tynemouth board in '5 ROMS + RAM' mode should also always initialise the CRTC controller after a reset, just as it would if the machine had been turned on from cold, so you should see the CRTC IC being accessed shortly after the end of the reset pulse - we did seem to be getting that and the next step is maybe to confirm that is still the case and then maybe try to catch the other signals (like read / write) going to the CRTC controller.

Your job for the moment though is to try to master the use of the SINGLE sweep mode because we really need that to work.
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Old 25th Jul 2023, 10:16 pm   #328
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Default Re: Commodore PET 4032/8050/3022

Tynemouth board fitted, ROM and RAM enabled.

Trigger set to Single on Channel 1 (pin 40 of the 6502) rising. Channel 2 is Pin 12 of UE13.

This is all I can get it do consistently do after a frustrating period.

Do I have something set wrong? The trigger value for example?

Colin.
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Old 25th Jul 2023, 11:19 pm   #329
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Default Re: Commodore PET 4032/8050/3022

At 5uS /DIV you are probably not allowing enough time between the rising edge of RESET and the point where the Tynemouth board gets around to trying to initialise the CRTC. If there is any such activity it is probably somewhere away off the screen to the right, I see you've also moved Channel 1 down to the lower half of the screen and channel 2 to the upper half - no problem with that really but until now you have had channel 1 in the upper half and that has been your established practice, now it's suddenly the other way around. Try increasing the Time / Div time into the higher (longer) uS or low Ms area, and try again.

Have you discovered how to re-arm the sweep trigger when in SINGLE mode?

Where did the sniper crosshairs come from, and why are the traces now only going to half way across the screen? Unfortunately, not having one of those scopes, I'm just going to have to let you try to undo those effects yourself.
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Old 26th Jul 2023, 12:32 am   #330
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Default Re: Commodore PET 4032/8050/3022

I've actually just realised that the crosshairs have been there all along, but somehow the fact of the traces ending half way across the screen finally drew my attention to them.
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Old 26th Jul 2023, 8:17 am   #331
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Default Re: Commodore PET 4032/8050/3022

Looking at the Icons in the 'toolbar' along the top edge of the software screen I see, among others, 'PLAY' and 'PAUSE' buttons. I'm wondering if these function as RUN and STOP. When the scope is in a continuous trigger mode like AUTO or NORMAL, the PAUSE button probably just freezes and holds whatever happens to be on the screen at the time, and the PLAY button returns you to a 'live' display?

When you are in SINGLE mode, when the trigger conditions are met, the trace does one sweep and then stops. I'm thinking that to re-arm it so that it's ready to go on the next valid trigger condition, maybe you press 'PLAY'?

The instructions aren't very helpful in this respect.
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Old 26th Jul 2023, 10:08 am   #332
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Default Re: Commodore PET 4032/8050/3022

I will reset the software to default and start again later on.

My frustration is more around the lack of consistency I am getting with UE13 tests. I'm beginning to wonder if the new 6502 socket I installed is being flaky with the number of times I have inserted and removed round pin devices into it (Tynemouth board/NOP generator). I may well remove and insert a new one with a sacrificial socket inserted into that one for the devices to plug into.

In terms of the software, there are buttons at the top of the screen much like a cassette player with a 'play' and 'pause' icon - they are the Run and Stop functions. I have a touch screen which makes it slightly easier to operate as I need three hands for this job (which doesn't help my humour when the probes keep slipping off the pins).

What happens in Single mode is as you say, the software detects something on CH1 and freezes the screen with the Pause button 'pushed down' on the screen. Pressing the Play button starts the Single mode process again.

What actually happens is that when the Reset goes high, it immediately stops - I'm guessing this is working as designed but I'm not sure it gives me long enough to observe anything on CH2. I will play with a longer time/div setting.

Also, from the email from Tynemouth it looks very much like the CTRC does not get reset when using the Reset button on the Tynemouth board which is what I have been doing. I need to do as you suggest and jerry-rig something up on C50.

I have new probes coming today at least so hopefully some of the readings should be cleaner.

So. Reset the software to default settings, remove/replace the 6502 socket, install a reset 'switch' across C50, use new probes when they get here and report back later on today.

Colin.
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Old 26th Jul 2023, 10:22 am   #333
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Default Re: Commodore PET 4032/8050/3022

Quote:
Originally Posted by ScottishColin View Post
No logic analyser here I'm afraid.

Attached is the best test signal I can get with my two probes using the earth and voltage ports directly off the scope. I cannot get CH2 to be any better than this - no amount of turning the screw makes any difference.

Is this a problem with the probes?

Colin.
>>
>>
It may be worth getting one sometime, as could be very-helpful when wanting to look at many channels simultaneously - I bought one listed as 'New USB Logic Analyzer Device Set 24MHz 8CH', back in 2014 for only £5.89 with free delivery. although took 3wks to arrive from China.
And are still being sold for not much more, and now have to pay a bit extra for delivery - but still < £10 all-in (maybe cheaper than most replacement 'scope probes!)
They do come with those common 'Dupont' socket s (for 0.64mm square pin headers etc) leads, but have to buy the IC-pin 'grabber' clips, that are commonly-used / come with logic analysers) separately (Although only just over £1 for a set of 4 as an optional accessory alternative on marketplace listings for these) - Rather essentially once you go above 2ch's, as not enough hands to probe everything!

Although I'm yet to try mine (not sure it came with any software, or whether it works with many free-download / open-source? ones like Sigrok?)
But I've previously used rather more expensive USBee / Saleae ones at work, inc. SPI / I2C etc. decoding they do.
You may also be able to use multiple 8ch ones together, as 16ch ones tend to be rather more (although often much-higher sampling rates)
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Old 26th Jul 2023, 10:30 am   #334
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Default Re: Commodore PET 4032/8050/3022

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Originally Posted by ScottishColin View Post
I'll get on with this - just a photo to show you that the 6545 sits directly under the Tynemouth PCB so getting anything to pin 25 is a bit tricky....

Colin.
That's where those IC-pin 'grabber' test clips can come in handy, so can clip them on the required pins to extend them out, before fitting the board over these. The miniature 'twin closing in a v-shape forks', that are copies of the original grey HP-branded logic analyser ones and available in many colours sets for easy identification of what's connected, are rather better (and even usable on 0.05" pitch Sufrace mount etc. IC's) than those single u shape copper-strip type that tend to keep falling off.
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Old 26th Jul 2023, 10:38 am   #335
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Default Re: Commodore PET 4032/8050/3022

Thank you - I will go and take a look to see if I think I can handle one....

Looks like sigrok is the default software of choice - I'll take a look at that too.

Colin.


Quote:
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Quote:
Originally Posted by ScottishColin View Post
No logic analyser here I'm afraid.

Attached is the best test signal I can get with my two probes using the earth and voltage ports directly off the scope. I cannot get CH2 to be any better than this - no amount of turning the screw makes any difference.

Is this a problem with the probes?

Colin.
>>
>>
It may be worth getting one sometime, as could be very-helpful when wanting to look at many channels simultaneously - I bought one listed as 'New USB Logic Analyzer Device Set 24MHz 8CH', back in 2014 for only £5.89 with free delivery. although took 3wks to arrive from China.
And are still being sold for not much more, and now have to pay a bit extra for delivery - but still < £10 all-in (maybe cheaper than most replacement 'scope probes!)
They do come with those common 'Dupont' socket s (for 0.64mm square pin headers etc) leads, but have to buy the IC-pin 'grabber' clips, that are commonly-used / come with logic analysers) separately (Although only just over £1 for a set of 4 as an optional accessory alternative on marketplace listings for these) - Rather essentially once you go above 2ch's, as not enough hands to probe everything!

Although I'm yet to try mine (not sure it came with any software, or whether it works with many free-download / open-source? ones like Sigrok?)
But I've previously used rather more expensive USBee / Saleae ones at work, inc. SPI / I2C etc. decoding they do.
You may also be able to use multiple 8ch ones together, as 16ch ones tend to be rather more (although often much-higher sampling rates)
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Old 26th Jul 2023, 10:39 am   #336
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Default Re: Commodore PET 4032/8050/3022

Ah, I did notice that 'RESET' switch on the Tynemouth board. Could be worth looking to see what happens on the CPU RESET pin when you press that onboard RESET switch. If the CPU RESET pin goes low while that button is pressed then it DOES reset the system, and not just the Tynemouth board.

Even so, a reset switch connected across C50 is to be preferred because that will trigger a single, clean, hardware timed single low reset pulse and rising edge.

I don't know how hard it is to get to the underside of the PCB but if you are having difficulty keeping probes on pins, strip and tin the ends of a couple of foot-long lengths of insulated wire and spot-solder the ends to the relevant IC pads on the underside and bring the other ends out to where you can attach the ends to your probes. Probes usually come with a sort of push-on hook-clip attachment which makes it easier to attach them to measurement points and leave them there, freeing up your hands for other things.

As mentioned earlier maybe get the hang of SINGLE sweep mode by doing one-shot post-reset captures of signals which you *know* are going to be there, on the lower address lines for example.

Keep an eye out for 'IC test clips' going cheap, as they can be a good time saver when trying to monitor signals on IC pins. Problem is, you ideally need as many different sizes of test clips as there are sizes of DIP IC.

The blue connectors under the link below (from CPC) are the kind of thing I mean -

https://cpc.farnell.com/c/cable-lead.../ic-test-clips

As you can see they aren't exactly cheap from mainstream sources but you may be able to find them cheaper elsewhere. Ideally you would want a 40-pin one as well, but one intended to fit a 24 pin or 28 pin wide bodied IC could possibly be used on a 40-pin IC by placing it at the high end or the low end of the device under investigation. Anyway, these only really come under the heading of 'would be nice to have'.

Edit: Crossed with Owen, who I think was talking about something similar.
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Old 26th Jul 2023, 11:07 am   #337
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Default Re: Commodore PET 4032/8050/3022

As a matter of interest, my scope is a 6022BL which seems to have a logic analyzer function available - never used it. Would it be of more use for what we are trying to do here (section 5.1 of the manual link below).

http://www.hantek.com/Product/Hantek...2BL_Manual.pdf

Colin.
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Old 26th Jul 2023, 1:09 pm   #338
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Default Re: Commodore PET 4032/8050/3022

Quite useful if you can work out how to use it - as far as I can see, you run a specific 'BL' version of the software and maybe press a button to put it into logic analyser mode. You can trigger from one channel with the usual ability to specify rising edge / falling edge etc and you can monitor what is happening on up to 15 other lines. I could wish it had 32 inputs rather than just 16 but that would be churlish.

The main thing is - do you have the necessary means of connecting the analyser inputs on the scope box to any IC pins of interest?
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Old 26th Jul 2023, 1:32 pm   #339
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Default Re: Commodore PET 4032/8050/3022

With the analyser, we could examine what is (or is not) being sent to the CRTC initially by monitoring...

Code:
CRTC D0-D7 (8 pins) 

CRTC CS

CRTC R/W

CRTC E

CRTC RS

CRTC RESET (This would be the signal we would trigger from, rising edge)
With the right time / div setting, this would show us the first few bytes being transacted between the CPU and the CRTC.

Or, we could examine what data is being read from the UD6 ROM initially by monitoring...

Code:
UD6 D0-D7 (8 pins) 

UD6 CS

CPU R/W

RESET (This would be the signal we would trigger from, rising edge)
(You could attach the D0-D7 channels to anywhere on the unbuffered data bus and just leave them there while you move the chip specific connections from one place to another)

Speaking of ROMs, what are the part numbers on the standard ROMs in that machine? (if you are going to start using a logic analyser we may need to have a look at the EPROM code to get an understanding of what it should do, when).
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Old 26th Jul 2023, 1:50 pm   #340
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Default Re: Commodore PET 4032/8050/3022

I think I have opened a can of worms that is perhaps beyond me here. I'll work on post 332 first.

Colin.


Quote:
Originally Posted by SiriusHardware View Post
Quite useful if you can work out how to use it - as far as I can see, you run a specific 'BL' version of the software and maybe press a button to put it into logic analyser mode. You can trigger from one channel with the usual ability to specify rising edge / falling edge etc and you can monitor what is happening on up to 15 other lines. I could wish it had 32 inputs rather than just 16 but that would be churlish.

The main thing is - do you have the necessary means of connecting the analyser inputs on the scope box to any IC pins of interest?
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