ESP32 Forum

Hi,

My name is Sai and I work as a Device Support Engineer at BPM Microsystems. We provide third party flash programming solutions to our customers. One of our customers is interested in programming the ESP32-PICO-MINI-02 on our programmers. Could you please provide me with the flash programming specifications for this device? We are willing to sign an NDA with you if needed. Thank you.

Hiya! First of all, this is not really a support forum; if you need more technical specifications, I'd suggest you reach out to sales@espressif.com. I can give you a general overview, though: these modules contain the ESP32 silicon and that chip is generally programmed using the UART pins plus reset and IO0 via the bootloader on the baked-in ROM. This is generally done using esptool.py, but we also have a C library that can do this as well. The serial protocol in use is described here, but as both the program and the library mentioned are open-source, you can also use the code as a reference. (Also note that generally, we do not require NDAs for things as mundane as knowing how to program our chips.)

Hi ESP_SPrite,
Thank you for the reply. I understand that the python code has details with regards to the flash and security keys burining. However, we need the underlying documentation like a device datasheet with schematics which was used to develop this tool. That way we can emulate this process to program multiple of these devices at the same time.
For example, if our customer wants to program a NOR flash, we get a document from the NOR flash manufacturer regarding how to access the flash, how to program it and how to erase it etc. I am attaching a data sheet for a sample NOR flash for reference. Can we get documentation like this? Kindly advise. Thank you.

So first of all, there's no way to get to the internal flash directly; you must program these modules via the UART of the ESP32. Secondly, the schematic on how to program it using that is not complicated: look up e.g. the devkitC schematics, or check the datasheet of the ESP32. Basically, you need to control GPIO0 and EN of the module to get it into download mode, then use the provided code or protocol to flash the module over an UART connection to TxD0 and RxD0. (Also make sure the other strapping pins have the correct levels - see the datasheet of the module for more info.) There is no such thing as a datasheet for this module wrt programming - as stated before, the serial protocol description I linked is the closest you can get, and this is easiest to implement using the C library I also linked (although you obviously can also write your own implementation)