Hi all,

I see many USB controller drivers implement usb_dc_ep_write function with one copy, copy the data (passed to usb_dc_ep_write) to one self’s buffer then do the transfer.

Do I need do this when implementing one new USB controller driver? Does the Zephyr USB stack limit the data (pass to usb_dc_ep_write) is in RAM?

The function prototype is as follow:

int usb_dc_ep_write(const u8_t ep, const u8_t *const data,

                  const u32_t data_len, u32_t *const ret_bytes)

Mark Wang

Thanks