Xiao ESP32-S3 Plus

[Vacant0mens]

Build Request

I'm working on a project that requires LoRa, and the Seeed Studio Xiao ESP32-S3 with the SX1262 Hat fits my use case perfectly.

Unfortunately, there isn't a specific firmware build/port for it, only the same board but with the Sense/Camera hat, and I don't know enough about the build process of CircuitPython to make a new port for this particular board+hat combo.

Would someone with experience updating and building the CircuitPython firmware be able to put this together for me?
I would appreciate it very much, and hopefully I'm not the only one that would like to see this get done.

Sub-Request

On the SX1262 hat, the LORA_BUSY pin is connected to GND via the B2B connector's Pin 2. It would be nice to have that pin from the SX1262 be available in the firmware, even though it's not in usable in this particular combination of hardware. Later in my project, I'm going to bypass the B2B connector for the LORA_BUSY pin to be able to use it in my code.
This part is not relevant for the ESP32-S3 Plus.

Side Note/Related Question

Why are the firmware builds so specific?

Reason for asking: The Xiao ESP32-S3 Sense (which is basically a Xiao ESP32-S3 ProPlus with a Camera hat) has a build all on its own so that makes it difficult to use CircuitPython with the same board but with a different hat. The only difference would be which pins are already in use/connected to the hat, so a generic Xiao ESP32-S3 [|Plus] build would've covered most hats for this device, especially if the build included all the available pins in the B2B connector.

Again, I don't know much about how the firmware builds work, so maybe someone can answer that for me in the comments.

[anecdata]

Builds for 3rd-party boards are usually done by the manufacturer or a community member, so it depends on their priorities. I tend to agree with you that a basic build for the Pro would be useful, and perhaps even handle all of the hats in Python libraries.

Also note that the SX1262, afaik, is not yet supported in CircuitPython. If it was, it could be used with the https://github.com/adafruit/Adafruit_CircuitPython_RFM9x or https://github.com/adafruit/Adafruit_CircuitPython_RFM libraries. Last I saw on the SX1262 from Adafruit was https://blog.adafruit.com/2024/08/28/the-sx1262-is-an-updated-lora-chip-so-we-made-a-breakout/

[anecdata]

For the Sense, there is camera support for the OV2640 in the core espcamera module, so with that hat it makes sense to have a separate build. But there is no core support for LoRa, so it would makes sense for that to be library-based on top of the Pro ("Plus"?) board.

[Vacant0mens]

Builds for 3rd-party boards are usually done by the manufacturer or a community member, so it depends on their priorities. I tend to agree with you that a basic build for the Pro would be useful, and perhaps even handle all of the hats in Python libraries.

My main ask is directed to the community members. It's kind of a shot in the dark, but I needed some help so I'm aiming for a kind soul out there. 🙏

Also note that the SX1262, afaik, is not yet supported in CircuitPython.

That's fine. I have a python module for it. So just a firmware build for the Xaio ESP32-S3 Plus/non-Plus would be sufficient. (I updated the title and my post to reflect this).

For the Sense, there is camera support for the OV2640 in the core espcamera module, so with that hat it makes sense to have a separate build. But there is no core support for LoRa, so it would makes sense for that to be library-based on top of the Pro ("Plus"?) board.

Okay, having the core camera module makes sense. Feels like that could be made a little more generic (like separate builds for "With Camera" vs "No Camera"), but maybe there's more in there than I'm expecting. 🤷

... on top of the Pro ("Plus"?) board.

Ah. Yes. You're correct, It's "Plus" not "Pro". Thanks for the correction. 👌

[anecdata]

Is 8MB vs. 16 MB flash the only difference between the vanilla Xiao ESP32-S3 to the Xiao ESP32-S3 Plus? It would be relatively easy given one to do the other. I'm sure you can get community help along the way. You probably want to start with the learn guide for building CircuitPython. Then probably use the Sense as a base, and strip away the camera (and any other differences). It may also help to review the PR for the Sense. Any board definition(s) will need fresh USB PIDs from Seeed.

Or, you can probably use the Sense firmware and just not exercise any camera features. Or is the problem with conflicts due to camera pins being reserved on the B2B connector?

[anecdata]

I don't see anything about the Wio-SX1262 that uses the B2B connector. The connections from the Xiao to the Wio seem to be only via the main header pins.

Also... could be out-of-date product pages or actual differences, but the Xiao ESP32-S3 with the SX1262 Hat page shows an ESP32-S3 with 8MB flash but no PSRAM. That may be sufficient for your needs. But the product page for the standalone Xiao ESP32-S3 and Xiao ESP32-S3 Plus show the base unit with 8MB flash and 8MB PSRAM, and the Plus with 16 MB flash and 8 MB PSRAM.

[Vacant0mens]

I don't see anything about the Wio-SX1262 that uses the B2B connector. The connections from the Xiao to the Wio seem to be only via the main header pins.

Check this schmatic (pdf)
It's listed in the web page that I linked in my original post.

Also... could be out-of-date product pages or actual differences, but the Xiao ESP32-S3 with the SX1262 Hat page shows an ESP32-S3 with 8MB flash but no PSRAM. That may be sufficient for your needs. But the product page for the standalone Xiao ESP32-S3 and Xiao ESP32-S3 Plus show the base unit with 8MB flash and 8MB PSRAM, and the Plus with 16 MB flash and 8 MB PSRAM.

8mb is will work for what I need. The PSRAM very well could just be accidentally omitted in the newer product page. So far I've been working with a slightly different device that has 8mb of SRAM, so the Xiao should be fine. LoRa is pretty light on resources in general.

Or, you can probably use the Sense firmware and just not exercise any camera features. Or is the problem with conflicts due to camera pins being reserved on the B2B connector?

You probably want to start with the learn guide for building CircuitPython. Then probably use the Sense as a base, and strip away the camera (and any other differences).

yeah, the defined pin classes are named after the camera pin functions, and there are no aliases for the camera pins, and there's no definition for some of the ones that the LoRa hat uses, so using the Sense firmware for the LoRa hat doesn't work out very well. I already tried. And I tried other firmware's, but they didn't have the correct pins defined.

This is the main reason I was suggesting that a Xiao ESP32-S3 Plus (generic) build would be a good idea.

Also, I don't have a Linux machine to work with, so I was hoping someone who already knew what they were doing would be able to help out.

[anecdata]

Keep the issue open, you may find a kindred spirit who also wants the R8 (flash only), N8R8, or the N8R16 base board(s).

The way I read the schematic, the LoRa pins on the B2B connector are duplicates of the main header pins. LoRa uses GPIO 1-5 and also the SPI pins GPIO 7-9, leaving 3 GPIO pins unused on the main headers. All of these pins are defined and available in the board module, and you can use the board.SPI() Singleton for SPI. I think you can use the Sense definition as-is with the LoRa hat.

The Sense firmware is for the N8R8 board (8 MB PSRAM, 8 MB flash), it probably won't work for the flash-only or 16 MB flash variants (but there may be firmware for other boards that matches PSRAM and flash for those).

[Vacant0mens]

Keep the issue open, you may find a kindred spirit who also wants the R8 (flash only), N8R8, or the N8R16 base board(s).

The way I read the schematic, the LoRa pins on the B2B connector are duplicates of the main header pins. LoRa uses GPIO 1-5 and also the SPI pins GPIO 7-9, leaving 3 GPIO pins unused on the main headers. All of these pins are defined and available in the board module, and you can use the board.SPI() Singleton for SPI. I think you can use the Sense definition as-is with the LoRa hat.

I'll give it another shot, but it didn't work when I tried it before.

[anecdata]

It would help to share your code, and a link to the library.

[Vacant0mens]

For my code, I would share it if I could. It's in a private repo, and it's got a lot of layers.

The hard part is that the module I have for the SX1262 I got from someone else on GitHub, and it requires passing in the pins, not the SPI interface. I'm not sure why that is, but maybe I can refactor my copy of it to take a new parameter for an SPI class instead of each individual pin.

The module I borrowed for my project is here: ehong-tl/micropySX126X
I copied it to my own repo and made some changes specific to my project, but it's pretty much the same still.

[bablokb]

I recommend that you try the build for the Adafruit QT Py ESP32-S3. This board is pin-compatible to the XIAO standard.

[anecdata]

I don't know which Xiao board you actually have in hand, but there are two QT Py ESP32-S3:

• 8 MB flash, no PSRAM (this firmware would match the Xiao with 8 MB flash, no PSRAM - Or, 8 MB flash and 8 MB PSRAM but the PSRAM wouldn't get used)

• 4 MB Flash + 2 MB PSRAM (I don't think this firmware could be used with any of the Xiao)

Other alternatives are firmware for boards that match the flash and RAM config of the board you have, and have the pins you need exposed. Some possibilities are:
https://circuitpython.org/board/adafruit_metro_esp32s3/ (16 MB flash, 8 MB PSRAM)
https://circuitpython.org/board/espressif_esp32s3_devkitc_1_n8r8/ (8 MB flash, 8 MB PSRAM)
https://circuitpython.org/board/unexpectedmaker_pros3/ (16 MB flash, 8 MB PSRAM)

Or, the Sense firmware on a 8 MB flash + 8 MB PSRAM Xiao ...I think the pins would be like this:
clk : SPI CLK pin - board.SCK
mosi : SPI MOSI pin - board.MOSI
miso : SPI MISO pin - board.MISO
cs : NSS pin - board.D3
irq : DIO1 pin - board.D0
rst : RESET pin - board.D2
gpio : BUSY pin - board.D1