Home
JAQForum Ver 24.01
Log In or Join  
Active Topics
Local Time 16:37 19 Jul 2024 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 : CMM2 G2 V2 design files

     Page 2 of 2    
Author Message
joker
Newbie

Joined: 06/02/2024
Location: Germany
Posts: 25
Posted: 07:09pm 06 May 2024
Copy link to clipboard 
Print this post

Hi,
Yes, the LED is supplied with 3V3 but I need a TTL signal to feed the signal into my logic.
I solved the issue now with a small level shifter:

There is a 10k pullup to 5V on the blue line, which is not shown here.
This gives me nice 0/5V signal if the LED is ON/OFF.

Was not as complicated as I thought. :-)

Cheers
  Matthias
 
joker
Newbie

Joined: 06/02/2024
Location: Germany
Posts: 25
Posted: 04:04pm 07 May 2024
Copy link to clipboard 
Print this post

Hi,
It seems that my last delivery from JLCPCB was not as spotless as expected.
The last board does not work.
I can program it and everything looks fine but the board does not start up.
5V and 3V3 are there, green LED is on, but that's it.

Any hints where to look at?

I don't think it has something to do with it, but I reprogrammed the board with an older firmware. But putting 2b11 back on doesn't change anything. The board is still dead.

Best Regards
 Matthias
 
matherp
Guru

Joined: 11/12/2012
Location: United Kingdom
Posts: 8673
Posted: 06:01pm 07 May 2024
Copy link to clipboard 
Print this post

Try erase all before programming. I've found this necessary on a couple of boards but I don't understand why
 
joker
Newbie

Joined: 06/02/2024
Location: Germany
Posts: 25
Posted: 03:09pm 08 May 2024
Copy link to clipboard 
Print this post

Thanks. I will try this

Matthias
 
joker
Newbie

Joined: 06/02/2024
Location: Germany
Posts: 25
Posted: 05:39pm 08 May 2024
Copy link to clipboard 
Print this post

  matherp said  Try erase all before programming. I've found this necessary on a couple of boards but I don't understand why


Thank you very much. Your hint worked. We are back to 5 out of 5  
I would never have thought about a full erase. I'm so happy now.

Cheers Matthias
 
matherp
Guru

Joined: 11/12/2012
Location: United Kingdom
Posts: 8673
Posted: 07:48am 04 Jul 2024
Copy link to clipboard 
Print this post

Grogster has also reported some boards not starting up properly and has sent me an example to diagnose.
The issue seems to be the RTC crystal circuit.
The crystal is 12.5pf and the two load capacitors C54 and C55 are specced at 10pf
This should give 5pf for the capacitors in series and allow 7pf for the board to give a reasonable match to the crystal.
Perhaps the capacitors supplied by JLC are incorrect? I can’t measure anything that low so no way to test.
I have fixed Grogster's board by simply removing C54 and C55 so if anyone else is having a problem they could try that.

There is an alternative fix with new firmware that clocks the RTC off the main 8MHz oscillator which is more accurate and eliminates the need for the RTC crystal entirely.
HOWEVER, the oscillator doesn’t run when the power is off so the DS3231 has to be enabled to avoid time loss with this firmware.
I can post this firmware if necessary.
 
Grogster

Admin Group

Joined: 31/12/2012
Location: New Zealand
Posts: 9187
Posted: 01:21am 08 Jul 2024
Copy link to clipboard 
Print this post

Yes, I had three boards that would not start from my last batch.
Following Peter's advise after he played with the board I sent him, I simply removed C54 and C55 from the other two boards I had here that would not start, then they started up just fine.  

Standard firmware.

I will most likely simply leave these caps off the BOM for the next batch of boards, or substitute a lower value that Peter suggested to me during our emails.

But so far three out of three boards that would not start, started just fine if you remove the two load caps, so I will probably get at least some boards made with those caps simply left off and see how we go.  
Smoke makes things work. When the smoke gets out, it stops!
 
PilotPirx

Regular Member

Joined: 03/11/2020
Location: Germany
Posts: 67
Posted: 02:44pm 08 Jul 2024
Copy link to clipboard 
Print this post



The IR receiver does not work on my board. When signals are received, they look like a capacitor charge/discharge curve. In the circuit diagram it looks like there is a 10µF capacitor on the signal output. This cannot be correct. I assume this is to buffer the supply voltage. Has anyone tested this? Is there an error in the circuit diagram?
 
phil99

Guru

Joined: 11/02/2018
Location: Australia
Posts: 1900
Posted: 09:39pm 08 Jul 2024
Copy link to clipboard 
Print this post

  Quote   I assume this is to buffer the supply voltage.
Yes, remove the capacitor and solder it between pins 2 & 3 on the underside of the board.
 
matherp
Guru

Joined: 11/12/2012
Location: United Kingdom
Posts: 8673
Posted: 07:37am 10 Jul 2024
Copy link to clipboard 
Print this post

Apologies for the IR circuit bug. Attached V2.1 gerbers/BOM/PLC  and schematic
NB: I've also changed the load capacitors for the RTC crystal to 6.8pf


Gerber_PCB1_2024-07-10.zip

BOM-PLC-SCH.zip
 
eparmstrong
Newbie

Joined: 17/04/2024
Location: United States
Posts: 2
Posted: 12:21pm 10 Jul 2024
Copy link to clipboard 
Print this post

As a note, after removing C54 and C55 from the two boards I had allowed them to boot as well.  Thanks for the update.
 
Grogster

Admin Group

Joined: 31/12/2012
Location: New Zealand
Posts: 9187
Posted: 01:40am 15 Jul 2024
Copy link to clipboard 
Print this post

Good to know.  

The next batch of boards I get made, will use the updated PCB layout and components as posted by Peter above.
Smoke makes things work. When the smoke gets out, it stops!
 
     Page 2 of 2    
Print this page


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

© JAQ Software 2024