I got one ESP32-S2 Saola board and I will be making some tests on this repository:
https://github.com/martinberlin/ESP32-S2
ESP32-S2 integrates a rich set of peripherals, with 43 programmable GPIOs which can be flexibly configured to provide USB OTG, LCD interface, camera interface, SPI, I2S, UART, ADC, DAC and other common functionality. ESP32-S2 provides the optimal HMI solution for touchscreen and touchpad-based devices.
The arduino-espressif32 is getting it’s finals touches of grace before being available and I will just do a small repository and try to test as much as I can and also make some benchmark comparisons.
In the first tests the impression is that most of the arduino framework is already working with a few exceptions. Not all the features are supported yet but they will be soon.
Sadly the deepsleep is still not optimized correctly in this first revisions of the Saola board and on 3.4 v I measured 0.79 mA/hour. On a good ESP32 board like tinyPICO it’s 0.08 mA/hour (10 times less) now that’s something you can plug to a battery and make it wake up every hour to do something.
Please note this is not a fair comparison at this point. It’s only a test with same firmware, same conditions and bypassing power regulator to see how much it consumes directly powering the board with the 3.3V pin.
On the other hand, making processor intensive tests like receiving UDP packets or receiving and decompressing at the same time, it showed similar speed with much less consumption than the ESP32.
But other than this small annoyance in this first board revision it’s a really promising product and very powerful System on a Chip. The feature list is impressive:
- Xtensa® single-core 32-bit LX7 microcontroller
- 43 programmable GPIOs.
- Standard peripherals including SPI, I2C, I2S, UART, ADC/DAC and PWM.
- LCD (8-bit parallel RGB/8080/6800) interface and also support for 16/24-bit parallel.
- Camera interface supports 8 or 16-bit DVP image sensor, with clock frequency of up to 40 MHz.
Please follow the repository and add issues or just leave a comment here if you want me to test any of the features and I will publish the results. Note that the only condition is that the results should be shared with the community on the internet. It’s all open-source, so we will keep the same spirit and share the results with everyone else.
Another example of ESP32-S2 in action, controlling 144 RGB Neopixels using Makuna library https://twitter.com/martinfasani/status/1267015931689144320
What GPIOs not to use in ESP32-S2
| GPIO | Description / default configuration |
| 0 | Pull-up |
| 26 | PSRAM pin |
| 45 | Pull-down |
| 46 | Pull-down – INPUT only |
| 43 * | default UART0 pin on S2 |
| 44 * | default UART0 pin on S2 |
* not sure if you should not use 43,44 but if you will use UART0 output in your project is the best you don’t use them
Important documentation
ESP32-S2 Technical reference manual (page 39-40 for the not-use GPIOs)
Fasani Corporation 