Strapping pins (vz GPIO2) on C3

[vanderjaan189]

I have seen many questions on strapping pins, but none that address my question exactly, which makes me worry if it is a silly question... I am designing a custom ESP32-C3 board with ESP32-C3-WROOM-02 module, and I see the three strapping pins and the explanation in the datasheet - I think for "normal" operation, I just want SPI boot mode (please feel free to correct me if I'm wrong), but nothing says what happens if I leave GPIO2 floating or if it gets pulled to ground. The technical manual and datasheet are pretty clear that both GPIO8 and 9 cannot both be low during boot, but it's oddly silent about pin2. Does anyone have any experience with this pin? Worst case scenario I will just put a jumper to test it out myself, but I am curious why there is so little documentation around it.

Also I plan on programming and debugging using OpenOCD and a J-Link, does this make any difference with the strapping pins? Thanks!

[john11]

Hi,

IO2 + IO8 should be pulled up
IO9 you can leave floating and ground when you want it to go into download mode

At least that's what I'm doing.

-- john

[TianAnCai]

What you said is What excatly I am worried about.

There is little descrition about IO2 in the guideline and I do not see IO2 be pulled up or down in the schematic of the official deckitC.

I want to have a Automatic Download Circuit in my design so I think it is better to pulled up the IO2 to make sure the circuit works.

Is there Anybody could answer the question or give me some advice ?

Thanks A Lot.

[dgduncan]

After reset, IO2 is set as input and in an high impedance state. Although not strictly necessary as I have made boards without a pullup, I would recommend it.