ESP32 PICOD4 PCB design

MCUism
Posts: 46
Joined: Mon Jul 15, 2019 9:25 am

ESP32 PICOD4 PCB design

Postby MCUism » Sun Jan 05, 2020 10:27 pm

Hey guys,

I'm designing my custom ESP32 PICO D4 board where I am using Rainsun 2.4GHz PCB antenna. I have couple of doubts here

1. Can I remove the Impedance matching circuit as the input impedance of ESP32 and antenna is 50 ohms? So I don't see any compelling situation for me to include the impedance matching circuitry.

2. VDD_SDIO is the MTDI pin in PICO D4? Because I didn't find any such pin named MTDI in the reference document provided by Espressif.

I have attached a link to my design below. Please suggest any improvements to my design. Do I need to connect a crystal oscillator or does ESP32 PICO internally have one?

https://photos.app.goo.gl/6azn3CWshxhA6Avi7

username
Posts: 179
Joined: Thu May 03, 2018 1:18 pm

Re: ESP32 PICOD4 PCB design

Postby username » Tue Jan 07, 2020 10:58 am

There are issues with your schematic. Like no pullup on the EN and GPIO wires.
Espressif has hardware References. I would start there.
https://docs.espressif.com/projects/esp ... -reference

MCUism
Posts: 46
Joined: Mon Jul 15, 2019 9:25 am

Re: ESP32 PICOD4 PCB design

Postby MCUism » Tue Jan 07, 2020 3:50 pm

@username Thanks for the reply. I have read in ESP32 PICO D4 datasheet that they have an internal pullup pin on IO0 and EN pins which means when they are left unconnected then they are internally pulled up.

username
Posts: 179
Joined: Thu May 03, 2018 1:18 pm

Re: ESP32 PICOD4 PCB design

Postby username » Tue Jan 07, 2020 4:11 pm

I have read in ESP32 PICO D4 datasheet that they have an internal pullup pin on IO0 and EN pins which means when they are left unconnected then they are internally pulled up.
True, but its so weak that by the time you add the caps to the En pin it will not be enough. It would be better to follow the examples.

MCUism
Posts: 46
Joined: Mon Jul 15, 2019 9:25 am

Re: ESP32 PICOD4 PCB design

Postby MCUism » Wed Jan 08, 2020 3:42 pm

Thanks for the info. I have modified my design now. I have a doubt regarding routing my PCB. Do I have to take any special care while routing my antenna? I have attached my routed pcb below. (Note: Ground plane routing is pending yet.)

https://photos.app.goo.gl/MP9g43WQEEoMVbT18

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