On our T20 based board is an USB hub (Microchip USB2514B). An external USB touch controller is connected to one of the downstream ports of the hub.
While a warm- or coldboot the hub switches off the USB-power (VBUS, 5V) for about 220 ms. This time interval is too short for the voltage to go down properly and the USB touch controller hangs up.
Is there any way to extend the power-off time?
Currently there is no way to extend the reset time or the time when the 5V comes up.
According to the DataSheet there is a RESET_N pin on the HUB controller. Would it be an option to either set that pin to 0 (reset) in using the gpio.bootconf and revert once the image is running? If you know when you do a software reset, you could also already put that pin to reset before resetting. Not sure this would help, probably not.
One other option would be that you delay the 5V for this device on your carrierboard for every boot.
