USB Host: number of endpoints limited to 8

[clydeps]

I'm trying to talk to a 4 port usb-serial chip, which needs 9 endpoints (control plus 2 each for each port, i.e. 4 interfaces.)

When I try to claim the fourth interface, it fails with NOT_SUPPORTED error, and I believe this is due to the number of channels available being only 8, as defined in components/hal/include/hal/usbh_hal.h:

Code: Select all

#define USBH_HAL_NUM_CHAN                   8

Firstly, am I right in my assumption that this is the limiting factor?
Secondly, am I to right assume that the only work-around would be to use a custom version of the SDK?

[clydeps]

Ah, it seems this is a hardware limitation of the ESP32-Sx chips.

[chegewara]

esp32 P4 should have EP0 + 15 endpoints, at least according to very old datasheet you can find on internet.