I want to use GPIOs (Interrupts) which would also generate an USB message. The GPIO examples in KIT-003 sample file are without any USB connectivity (just for internal ARM9, OK so far).
I am not an expert on USB. Would it be possible to generate an USB message (from device to host) when a GPIO was triggered, the ARM9 has handled a GPIO Interrupt? Or is it necessary to poll the status via USB? Host has to request the status of GPIO, peridocially? Or could I send an asynchronous, unsolicited USB message to inform host that GPIO (something) is available to be drained?
Is there an example how to use GPIOs (Read and Write) via USB plus ARM9 where it would do something on GPIO trigger (e.g. generate the USB packet to be sent to host or prepared to be drained later by host (when "polling")?
The host is expected to initiate communication with the USB device. The host will have to keep pollling the status of the GPIO if your application needs that, The FX3 firmware can get the interrupt on GPIO trigger, but you need to send it to the host. How can the host know when it should read the status. So, instead, the host can send a Vendor request, on which the device will check the current status of the GPIO and inform the status to the host.