The ESP8266 is about six years old now and the ESP32 is getting more mainstream every day. Unsurprisingly, Espressif is developing even newer product and the ESP32-S2 was in the hands of some beta testers last year. Now it is finally landing as “final silicon” samples in people’s hands. [Unexpected Maker] got a few and a prototype development board for the chip and shared his findings in a recent video.
The ESP32-S2 has a single core LX7 running at 240 MHz along with a RISC-V-based coprocessor. Onboard is 320K of RAM and 128K of ROM. You might notice this is less than the ESP32. However, the device can support up to 128MB of external RAM and up to 1GB of external flash. It also supports USB, although the prototype module appears to have an external USB chip on it.
There are no extras like Bluetooth, Ethernet or CAN, but there are 43 GPIO and 14 touch sensors. There are other differences, some plus and some minus. There are two UARTs, down from the ESP32’s three. However, there’s also a camera interface and more crypto hardware. There is a way to use time of flight measurements with WiFi to estimate position, which could be interesting if it works well.
The big news, though, is automatic power management that claims 5uA in idle mode and 24uA [while running the ULP coprocessor] at 1% duty cycle. Honestly, it almost seems like the -S2 is really meant to be a secure ESP8266 more than a next-generation ESP32. That’s not totally fair since the new board has lots more processing power than an ESP8266, but still.
We looked at the -S2 when Espressif announced it. The ESP-32 could operate on relatively low power with effort, but the -S2 should make even lower power operation easier.