ESP32 Forum

There doesn't seem to be a solution which can be used simultaneously with WiFi and BT.
With regards to lowering the APB frequency, we will have a solution for this, but currently this is not supported because CPU frequency would be lowered to the same value, and FreeRTOS as well as timekeeping functions expect certain constant values of CPU frequency and APB frequency. We will have a solution for dynamic changing of APB/CPU clocks in the next major version (3.0).

Would the Ethernet still work with lowered APB Clock ? I would expect it as the clock comes from an external source.

For Ethernet in 100Mbps mode, lowest APB clock frequency can be 50MHz. For 10Mbps, lowest is 5 MHz.

Thanks to both rudi and ESP_igrr for all the info and clarifications provided in this thread.

Is there still no way using the device with 20k bps?

Starting with revision 2 of the ESP32 there is a way to configure lower can baud rates; for the newer chips the function of bit 4 of the interrupt enable register changes from "enable wakeup interrupt" to "divide BRP by 2". Here is a pull request to the openvehicles project that allows use of 33.333K, 50K, and 83.333K baud:

• https://github.com/openvehicles/Open-Ve ... 3/pull/587

Testing was done with a V3 ESP32-WROVER.