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GregZone
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Joined: 22/05/2020
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Posted: 08:49am 18 Jun 2020

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matherp said What you need to do is remove the resistor, disconnect everything, and measure the resistance between pin 40 and GND. It should be completely open circuit.

Test successfully completed with new b1q version and resistor removed. All good, as with resistor. Just noting my comment above re. the Busy LED.

With everything disconnected Pin 40 to GND measures ~30M / ~370K depending on test lead polarity. However note that I get the same readings measuring Pin 40 to 3.3V.
ie. I believe Pin 40 appears to be floating?

matherp said Stupid question but you don't have a bare board sitting on a bench with any conductivity - e.g. antistatic surface

Certainly not a silly question, especially if we have floating inputs?

No, the board is certainly not sittng on anything with conductivity! Although it's been raining heavily today so the air is pretty moist, even with the dehumidifier going.

matherp
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Posted: 08:58am 18 Jun 2020

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Quote With everything disconnected Pin 40 to GND measures ~30M / ~370K depending on test lead polarity. However note that I get the same readings measuring Pin 40 to 3.3V.

Your readings could be a meter issue but with a Fluke 87 I get zero in both directions.

One more test. In the attached I've re-instituted the pin 40 test but I've added a 250mSec delay before it to give the internal pullup time to overcome any capacitance/ bleed resistance on the pin.

Please try this without a resistor and see if the fault returns

CMM2V5.05.03b1q.zip

GregZone
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Joined: 22/05/2020
Location: New Zealand
Posts: 114

Posted: 08:59am 18 Jun 2020

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matherp said GregZone

Please could you do another test.

With the CMM2 running normally

SETPIN 40,DIN,PULLUP
? PIN(40)

Then you may wish to repeat on all the other valid pins

Here ya go...

> ? PIN(40)
Error: Pin is not an input

> SETPIN 40,DIN,PULLUP
> ? PIN(40)
1
>

Can you explain the purpose of this test? The PIN appears to be returned to "not an input" upon a reset.

GregZone
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Joined: 22/05/2020
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Posted: 09:01am 18 Jun 2020

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matherp said Your readings could be a meter issue but with a Fluke 87 I get zero in both directions.

My readings were with my trusty Fluke 179. Which I totally trust! :)

matherp
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Posted: 09:02am 18 Jun 2020

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Quote Can you explain the purpose of this test?

That is what the firmware does to check for reset, it then does a SETPIN 40,OFF

Our posts crossed, please see my previous post. Thanks for your efforts.

The fact you are seeing some resistance suggests to me that there is some contamination of the PCB which is probably the route cause of the issue
Edited 2020-06-18 19:04 by matherp

GregZone
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Posted: 09:12am 18 Jun 2020

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matherp said One more test. In the attached I've re-instituted the pin 40 test but I've added a 250mSec delay before it to give the internal pullup time to overcome any capacitance/ bleed resistance on the pin.

The issue returns with this firmware version. ie. That's a test fail.

matherp said The fact you are seeing some resistance suggests to me that there is some contamination of the PCB which is probably the route cause of the issue

Well, I could throw my board into my Ultrasonic PCB cleaner, but I think this is not really the answer.

Especially noting that CircuitGizmos is reporting the exact same issue with his new JLC assembled PCB's.

So does this mean that for your pin 40 function, a PCB revision is necessary to add an external Pin 40 pull-up resistor?

matherp
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Posted: 09:24am 18 Jun 2020

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Quote So does this mean that for your pin 40 function, a PCB revision is necessary to add an external Pin 40 pull-up resistor?

It hasn't been necessary for

8 machines I've built
A number of machines Grogster has built
A number of machines WW has built
6 machines distributed to the original development group
Machines hand crafted by KeepIs and SWA-Guy

There is an issue with CGs versions that needs understanding and fixing otherwise other issues such as the possible impairment of SDcard operation may be there and impacting users

matherp
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Posted: 09:43am 18 Jun 2020

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GregZone

One last try please without resistor

CMM2V5.05.03b1q.zip

let me know what happens. Thanks

GregZone
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Joined: 22/05/2020
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Posts: 114

Posted: 09:49am 18 Jun 2020

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matherp said

Quote So does this mean that for your pin 40 function, a PCB revision is necessary to add an external Pin 40 pull-up resistor?

Agree. CircuitGizmos does appear to be the common factor with this issue.

However, understanding that you are setting the pin as an input with internal pull-up, and then testing for it being pulled low, then this seems perfectly reasonable...

So... silly question... Are you 100% sure your test code change did correctly implement a 250ms delay before reading the input value? Just checking, as a 250ms delay would seem quite reasonable to allow the pin to stabilise, and clearly the internal pull-up is effective.

TassyJim

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Posted: 09:54am 18 Jun 2020

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I have been running with a relatively long 40 way cable and a breadboard attached with no problems with random rests which is why I didn't think to consider it as a possibility.

It was only when I deliberately forced a reset while monitoring the backup ram that I experienced exactly your fault.

The rest was easy.

I agree with Peter that finding the route cause of the problem is important for continued reliability.

Prevention is always better than cure.

Jim

GregZone, can you measure the resistance to ground with the Waveshare module removed.
Edited 2020-06-18 19:56 by TassyJim

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matherp
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Posted: 09:59am 18 Jun 2020

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Quote So... silly question... Are you 100% sure your test code change did correctly implement a 250ms delay before reading the input value? Just checking, as a 250ms delay would seem quite reasonable to allow the pin to stabilise, and clearly the internal pull-up is effective.

In the latest version I check the pin 3 times at 100mSec intervals and only if all three read low do I reset

KeepIS

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Joined: 13/10/2014
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Posted: 10:15am 18 Jun 2020

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Just for reference to something mentioned by Peter:

Quote other issues such as the possible impairment of SDcard operation may be there and impacting users

Full size SD Card reader on flying leads, 8, 16, 32 and 64 GB Micro SanDisk (via adaptor) all perfect, and I've been hammering the SD, cheap Jaycar adaptor with resistors for Level shift and all, this one would not work on the ARM-H7 CMM2 loves it.

NANO Inverter: Full download - Only Hex Ver 8.1Ks

GregZone
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Joined: 22/05/2020
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Posts: 114

Posted: 10:26am 18 Jun 2020

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TassyJim said GregZone, can you measure the resistance to ground with the Waveshare module removed.

As you suspected, my resistance measurements were with the Waveshare in place. The high resistance values I measured would have been due to the SoC connected pin.
However, the values measured would not have impacted the correct pull-up with the internal pull-up resistance (as shown by the PIN(40) tests).
Given the potential for impairment of the 80pin header sockets, I'm reluctant to remove the Waveshare board again simply to verify a higher restnace value / open circuit.

matherp
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Posted: 10:30am 18 Jun 2020

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Have you tried the software I posted at 9:43?

GregZone
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Posts: 114

Posted: 10:36am 18 Jun 2020

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matherp said In the latest version I check the pin 3 times at 100mSec intervals and only if all three read low do I reset

YES! We have success. Nice work.

So, I think this just leaves:

1. After reset the Red LED remains constantly ON, until the SD Card is first accessed (eg. a LS command). Then it reverts to correctly lit only during access.

2. Throughout I have still seen occasional unexpected key repeats.

GregZone
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Posts: 114

Posted: 10:37am 18 Jun 2020

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matherp said Have you tried the software I posted at 9:43?

We just cross-posted (see prior post). Sorry for the delay, it's getting quite late here so I'm about to sign-off for the night.

Thanks for your excellant work on this issue!

matherp
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Posted: 10:40am 18 Jun 2020

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Quote 1. After reset the Red LED remains constantly ON, until the SD Card is first accessed (eg. a LS command). Then it reverts to correctly lit only during access.

This is correct, it indicates a USB keyboard has been enumerated. Try without the keyboard and then plug it in. See the user manual page 11

Quote 2. Throughout I have still seen occasional unexpected key repeats.

This suggests the keyboard isn't playing nicely and the S/W is missing the key up events. Have you tried different keyboards?

Quote YES! We have success. Nice work.

Not so fast - I've just coded round an underlying H/W problem - not a good solution
Edited 2020-06-18 20:45 by matherp

GregZone
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Posted: 11:00am 18 Jun 2020

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matherp said Not so fast - I've just coded round an underlying H/W problem - not a good solution

I'd suggest that slow settling time of the applied internal pull-ups is more likely related to PCB trace capacitance / inductance.

I've left my workroom for the night, so I haven't inspected the PCB routing associated with pin 40, but is it possible that this is a longer trace perhaps running alongside a ground trace or copper fill?
(Just thinking out loud with some end of day tired thoughts).

ps. Hopefully CircuitGizmos can replicate the last test successfully with his boards as well.

thwill

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Posted: 11:54am 18 Jun 2020

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Hi Peter,

Just updated to 5.05.03b1q and I am now seeing the issue where an edit made to a .bas file is being ignored when the file is being Run.

I can't reproduce this with a simple example, nor with Z-MIM R1, but it is happening consistently with my Z-MIM development version.

Do you want to take a look? How do you want the files?

Regards,

Tom

MMBasic for Linux, Game*Mite, CMM2 Welcome Tape, Creaky old text adventures

matherp
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Posted: 01:27pm 18 Jun 2020

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Quote Do you want to take a look?

Certainly need to get to the bottom of it.

Please try the following test version and let me know if the issue still occurs

CMM2V5.05.03b1r.zip

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