No Power on Cora Z7-10 USB Type-A Connector

[RyanW]

Hello, I have a Cora Z7-10 and it appears that the USB Type-A functionality of this board is not working. When measured, I get 0 volts across the power rails on the USB 2.0 pins. I also checked this on the single core version of the board I have and I got the same results. I can't access any peripheral USB devices I am trying to hook up to the board due to this issue. I tried to power the board with an external power supply thinking that maybe the USB was shutting down or not turning on due to some circuitry things, but after powering it in both USB and external modes, the USB Type-A port still seems to be inactive/has zero volts on its power rails. Everything else on the board appears to work well, and I have been using them for around a year now (just never tried anything with USB up till now). Is there something I need to do to enable the functionality of the USB host port for the Cora Z7-10/7s?

[JColvin]

Hi @RyanW,

You are correct that you will want to us the USB Host port that you'll want to power the board via a wall adapter as per the Reference Manual here: https://digilent.com/reference/programmable-logic/cora-z7/reference-manual#usb_host. On POR without any configuration the Type A USB OTG interface will not be providing any power because the CPEN output on the embedded Micochip USB3320 Transceiver Chip is at a logic low level so the power switch IC (IC4, on page 4 of the Cora Z7 schematic, https://s3-us-west-2.amazonaws.com/digilent/resources/programmable-logic/cora-z7/Cora+Z7_sch-public.pdf) will not enable the 5 V USBHOST_VBUS line.

Based on the USB3320 datasheet in section 5.6.3 (available for download from Microchip's website here: https://www.microchip.com/en-us/product/USB3320#document-table), CPEN is asserted by setting the DrvVbus or the DrvVubsExternal bit of the OTG Control Register (Table 7.1.1.7)

Thanks,
JColvin