Help needed to debug custom ESP32 Pico D4 PCB

diyoio
Posts: 5
Joined: Tue Mar 03, 2020 3:47 pm

Help needed to debug custom ESP32 Pico D4 PCB

Postby diyoio » Tue Mar 03, 2020 4:10 pm

Hello,

I designed a board based on different circuits available online and I just received my assembled board but I'm not able to program the ESP Pico D4 module. The USB connection is successfully made with my computer but I get a timeout error when trying to flash the module with ESPIDF.

This is what I checked for now :
  • All the connections seems to be OK, the only one I couldn't check is the ground connection below the module. I only did one small via to ground before I saw that ESP Pico Kit had several vias to connect the module to ground. Is it possible to check that module is connected to ground ?
  • All pins requiring 3.3V are connected to 3.3V.
  • IO0 and EN pins seems to be triggered correctly by the USB-UART module. (Quick check with an oscilloscope)
Am I suppose to see something on TX pin when I turn on power supply ? (I think i've read somewhere that the module sent messages at startup). This is my first real PCB project so any help would be greatly appreciated :)

You can find the schematics attached.

Thanks a lot !
Attachments
Schematics.png
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mikemoy
Posts: 627
Joined: Fri Jan 12, 2018 9:10 pm

Re: Help needed to debug custom ESP32 Pico D4 PCB

Postby mikemoy » Wed Mar 04, 2020 6:18 am

Nothing jumped out at me besides the fact that you seriously need to put 0.1uf bypass caps on every power pin.
Maybe someone else catches something.

diyoio
Posts: 5
Joined: Tue Mar 03, 2020 3:47 pm

Re: Help needed to debug custom ESP32 Pico D4 PCB

Postby diyoio » Wed Mar 04, 2020 12:26 pm

Thanks a lot ! Can this lack of bypass caps cause the module not to boot up ? Also, is there any way to verify that my module is grounded or not ?

mikemoy
Posts: 627
Joined: Fri Jan 12, 2018 9:10 pm

Re: Help needed to debug custom ESP32 Pico D4 PCB

Postby mikemoy » Wed Mar 04, 2020 1:28 pm

Can this lack of bypass caps cause the module not to boot up ?
Its hard to say every design and PCB is different.
Also, is there any way to verify that my module is grounded or not ?
I can't think of any with all the parts on the board. If the the ESP32 was the only part on the board you could use a multi meter in diode check mode across +3.3v and Gnd pin and you should see something other than a open circuit.

Did you poke the TX/RX pins with a scope to see if you see anything ?

diyoio
Posts: 5
Joined: Tue Mar 03, 2020 3:47 pm

Re: Help needed to debug custom ESP32 Pico D4 PCB

Postby diyoio » Wed Mar 04, 2020 2:39 pm

mikemoy wrote:
Wed Mar 04, 2020 1:28 pm
Did you poke the TX/RX pins with a scope to see if you see anything ?
Yep, 3.3V on both pins, nothing happens on TX but when I try to flash the module, I can see signal on RX pin...

Thanks for your help :)

mspider65
Posts: 4
Joined: Tue Jan 07, 2020 10:12 am

Re: Help needed to debug custom ESP32 Pico D4 PCB

Postby mspider65 » Wed Mar 04, 2020 5:20 pm

Exactly the same problem i have on my custom board.
viewtopic.php?f=12&t=14549

Did you also received the board recently from JLPCB?
Maybe is a faulty lot of ESP32 PICO D4.

diyoio
Posts: 5
Joined: Tue Mar 03, 2020 3:47 pm

Re: Help needed to debug custom ESP32 Pico D4 PCB

Postby diyoio » Thu Mar 05, 2020 8:06 am

mspider65 wrote:
Wed Mar 04, 2020 5:20 pm
Exactly the same problem i have on my custom board.
viewtopic.php?f=12&t=14549

Did you also received the board recently from JLPCB?
Maybe is a faulty lot of ESP32 PICO D4.
Yes, my board has also been printed and assembled by JLCPCB... Did you try to contact them ? I'll send them a message now to check with them...

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