Announced back in May by Espressif, it appears that beta silicon for the upcoming ESP32-S2 is now shipping to some community members, and one recipient, Seon Rozenblum from the Unexpected Maker, has put together an amazing first look review of the new silicon.
The new ESP32-S2 sits between the ESP8266 and the current ESP32 in Espresif’s product line. Although it is far more powerful than the ESP8266, the new ESP32-S2 has only a single core to the ESP32’s two cores. However that said, the single core of the ESP32-S2 is a Tensilica Xtensa LX7 running at up to 240 MHz, while the ESP32 dual core is an Xtensa LX6 which also run at 240 MHz. Yet the newer Xtensa LX7 core should be capable of more floating point operations per cycle which may go some way to help to make up some of the difference.
The ESP32-S2 shares the same ultra-low power co-processor with the ESP32, though it looks like it will be far more exposed to the main processor.
“Unlike the current ESP32 that has a lot of limitations on what the co-processor [cloud] do, the new co-processor on the ESP32-S2 is more like a proper CPU, with enhanced functionality, but no specific details are available just yet…” — Seon Rozenblum, the Unexpected Maker
But there are some other big differences between the ESP32-S2 and the ESP32. For most people, the biggest change is the addition of USB support, with the ESP32-S2 offering support for full-speed USB OTG, which means that you won’t need external silicon to talk to and program the chip.
That said, while the silicon supports USB, it’s not currently available in this version of the silicon, so the the module and board reference designs shipping to the community right now are still using external peripherals to support communication.
While the new chip still supports Wi-Fi 802.11 b/g/n, unlike the ESP32, there is no Bluetooth support. But there is support for Time of Flight (ToF) measurement, which is an interesting move into the indoor positioning space by Espressif.
The ESP32-S2 has 320KB of SRAM and 128KB of ROM compared to the ESP32’s 520KB of SRAM and 448KB of ROM. However the new ESP32-S2 has 43 programmable GPIO pins, compared to the ESP32’s 34 programmable GPIO pins, and also offers LCD and camera interfaces as well as the usual support for SPI, I2C, I2S, ADC, DAC, PWM, and UART. The chip can also support up to 1GB of external flash.
Finally, the new ESP32-S2 comes with better on-chip security features including support for RSA trusted application boot, and AES256-based flash encryption.
The ESP32-S2 is still in beta, and the final silicon design hasn’t been settled yet. So we can expect to see one or two more revisions before it starts to ship to consumers. When is that going to happen? I don’t think anyone outside of Espressif knows quite yet. However I’d expect to hear more soon, and possibly see final silicon towards the end of the year.