programming esp32 chip via serial / fttdi

[Ulf Holt]

I want to program some ESP32 chips using serial connection via FTTD USB connector. I have no problems programming the DEV-kits, but the chip is another ballgame. I know how to do program the ESP12-F chip, but the ESP32 refuse to connect. Recon I am missing connection to a pin. Try to set EN high via 10k and a push button to ground for reset. Same with GPIO0. Something else I need except for rx - TX and TX -Rx, and off coures power?

Best regards

Ulf

[Philip Knowles]

Don't know if this helps. Looks like GPIO0 & 2 need to be low on boot 

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From: sonof...@googlegroups.com <sonof...@googlegroups.com> on behalf of Ulf Holt <ulf....@gmail.com>
Sent: 21 March 2025 20:28
To: TasmotaUsers <sonof...@googlegroups.com>
Subject: programming esp32 chip via serial / fttdi

 

I want to program some ESP32 chips using serial connection via FTTD USB connector. I have no problems programming the DEV-kits, but the chip is another ballgame. I know how to do program the ESP12-F chip, but the ESP32 refuse to connect. Recon I am missing connection to a pin. Try to set EN high via 10k and a push button to ground for reset. Same with GPIO0. Something else I need except for rx - TX and TX -Rx, and off coures power?

Best regards

Ulf

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[Justin Adie]

When you say the chip, what do you mean?  Just the esp32 chip or a chip module that has the flash memory, regulators and oscillators needed for operation?

In either case you need to get the bootstrapping right.  But if you are using the bare chip you should make sure that your circuit connections to the oscillator and flash memory are good first.  I don't design many circuits from scratch any more.  I tend now to design with pads for the esp32 wroom 32 modules.

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[Justin Adie]

Can you share a photo of your setup?   

Building for the raw chip is not straightforward!

Fyi there is a chip only (esp32), a module (esp32 wroom 32) and a dev-kit (e.g. Node MCU) type solution.     The dev kit solutions have pins to connect with normally, modules are soldered directly to the target board and of course the same for the chip only solutions

For the flashing you would be best served by soldering temporary jumpers to the ground or 3.3v lines as needed for bootstrapping.  Remember also to use a full image that creates the partitions for you.  Easiest here is the web installer. 

On Sat, 22 Mar 2025, 10:25 , <ulf....@gmail.com> wrote:

I am thinking about the Chip, not the module. The serial connection works, and I can see messages from the chip. I can enable downloading using the Reset / Boot buttons (I'm using a simple breakout board), but cannot download code. Reason for not using the module instead is space issues.