Home
JAQForum Ver 24.01
Log In or Join  
Active Topics
Local Time 06:51 02 Aug 2025 Privacy Policy
Jump to

Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.

Forum Index : Microcontroller and PC projects : Console connection?

Author Message
davematt
Regular Member

Joined: 27/09/2011
Location: Australia
Posts: 55
Posted: 12:43am 28 Sep 2018
Copy link to clipboard 
Print this post

Hi all, Has this happened to anyone else?
Recently I've been driven to despair by stange console behaviour. Using the excellent MMedit, I can work for some time programming and debugging code, and then things go sour. Sometimes MMedit has trouble finding the com port, followed by complete inability to get a command prompt.
Rebooting the mite will give me the normal copyright message, but no prompt!
The scope shows the break signal getting to the mite, it shows 2 negative going pulses of a few microsecs.
Is this the normal picture?
The details:
Using Mmedit latest version, mmbasic 5.04.04, on a Mx170 freshly flashed.
Any suggestions most gratefully received...
Dave
PS same behaviour in teraterm...
 
Andrew_G
Guru

Joined: 18/10/2016
Location: Australia
Posts: 871
Posted: 01:49am 28 Sep 2018
Copy link to clipboard 
Print this post

Hi Dave - I'm a rank novice and haven't seen that specific problem but have you tried re-flashing the MM hex file to the chip, or even a different chip?
(Edit: I now see your comment about a freshly flashed chip but how about a different chip?)

Cheers, AndrewEdited by Andrew_G 2018-09-29
 
TassyJim

Guru

Joined: 07/08/2011
Location: Australia
Posts: 6283
Posted: 02:41am 28 Sep 2018
Copy link to clipboard 
Print this post

If MMEdit is having trouble finding the com port, it points to USB adapter issue.
Even a brief loss of the adapter causes Windows to sulk.

What adapter are you using and how are you powering your 'mite.
Some USB adapters don't have very good 3.3V available and that can cause grief if you are trying to run any sort of load from it.

The other common problem is the capacitor on pins 19/20

I assume by 'break signal' you are referring to control-C

Jim
VK7JH
MMedit
 
davematt
Regular Member

Joined: 27/09/2011
Location: Australia
Posts: 55
Posted: 01:30am 29 Sep 2018
Copy link to clipboard 
Print this post

Further to the above and thanks for these replies.
Sorry for the delay, Grand final weekend in sunny Victoria NOT!
In the middle of testing the ideas above I tried a Win 10 PC. Well I'm desperate...
So far it's working fine!
To me this would suggest a driver problem, but from that point I'm stumped. I've used the CP2102 converter and the Microbridge on three Win7 PCs with identical results. I don't understand how a standalone mite able to transmit the copyright message could receive the control C character, and then transmit nothing...
Plan H at the moment is to buy a Win 10 laptop, so you can see things is crook!
Dave.
 
cosmic frog
Guru

Joined: 09/02/2012
Location: United Kingdom
Posts: 302
Posted: 08:49pm 29 Sep 2018
Copy link to clipboard 
Print this post

I've had a lot of problems with the USB TTL serial things, from driver problems to sometimes working and then not working. In the end I started using the "old fashioned" 9 pin serial connector, this works great everytime. Now I have a rock solid, always there connection.

Dave.
 
Azure

Guru

Joined: 09/11/2017
Location: Australia
Posts: 446
Posted: 10:13am 01 Oct 2018
Copy link to clipboard 
Print this post

Can you elaborate a little more on the setup, is it a known MM PCB or your own config.

Are you powering it completely from the CP2102? What is connected to the MM (like an LCD and any other peripherals).

Do you have access to a scope to check things?
 
sagt3k

Guru

Joined: 01/02/2015
Location: Italy
Posts: 313
Posted: 10:55am 01 Oct 2018
Copy link to clipboard 
Print this post

Hi davematt
Can you try last version of Micromite Console?
link
Thanks
Antonio
 
davematt
Regular Member

Joined: 27/09/2011
Location: Australia
Posts: 55
Posted: 11:11am 01 Oct 2018
Copy link to clipboard 
Print this post

@Azure, I have one dil chip in a breadboard, and one SOIC chip on one of Mick's serial backpack boards. In each case, nothing else connected, external power, 10uf ceramic on pin 20, and check the ctrl C signal with a couple of different scopes.
At the moment I get no response at all with any of the Win 7 adapters, while the Microbridge and a Win 10 machine work normally.
At 38.4 kb, Ctrl C produces (consistently), a 25usec negative pulse, followed 50usecs later by 160usec pulse. This normally results in a burst of characters from the console Tx pin, and the arrow prompt in MMedit chat window. Communication and loading will then work.
Not so if otherwise. If the above is the correct pulse waveform, why will a fresh chip not respond?
Or are my pulses different from everyone elses? Hmmm...
 
Azure

Guru

Joined: 09/11/2017
Location: Australia
Posts: 446
Posted: 11:47am 01 Oct 2018
Copy link to clipboard 
Print this post

Someone else will hopefully be able to chime in on the Ctrl-C response waveforms (I have not checked them before), if not I can check on Wednesday (but not before).

You mention external power, what are you using for power and just to clarify - you are not using the power from your CP2102 adapter board to power the MM.
 
Print this page


To reply to this topic, you need to log in.

The Back Shed's forum code is written, and hosted, in Australia.
© JAQ Software 2025