I have found that the nRF52840 is not capable of being a USB host, it's peripheral only. I've concluded that from this devzone post and this infocenter entry.
You can use a microcontroller with USB host functionality and another communication protocol compatible with the nRF52840 or a USB bridge IC. I'm doing the same thing at the moment using an SPI to USB bridge.
guys do you have tried the Vinculum-II? I also want to connect a nRF5840 to a CDC Modem using AT commands a give it cellular functionality. at the moment no luck to make work the Vinculum II
I have a nrf52840-DK and Arduino USB Host Shield combo. Setting communication bits is just fine, I also can read the revision number.
I've stuck over a problem though. In code examples you've specified there is a loop waiting for OSCOKIRQ for PLL/internal oscillator to stabilize. Same loop is in every code for MAX3421e I was able to find.
OSCOKIRQ is never set on for me. There is a thread at Electrical Engineering StackExchange claiming it is a bug in MAX3421e. I doubt this is the case, it certainly would be noticed, at least by felis/USB_Host_Shield_2.0.
I am running nrf52840-DK connected and powered via USB, nothing is connected to the shield, I can set communication bits and read revision number. So I guess it is enough power for PLL, right?
My question is - have you seen this problem in your project? Was waiting for OSCOKIRQ working for you? Or you've just skipped this stabilization part?
Sorry for bugging you, but I am really desperate right now. (
As I have mentioned before, I haven't worked on this project in a long time.
I do however remember something along the lines of OSCOKIRQ not being set, and actually read the same thread at stackexchange. I think the problem back then was a lack of power because the nRF52840DK cannot provide enough current to the MAX3421E-EVKIT.
Try looking up the power specification for you board and checking if you're providing enough. If not, use an external power source.
