I designed a omap4-custom board, where i connect usbb1 interface to ULPI transceiver, the ULPI transceive is usb3320. however, among the 40 custom boards, there are 10 boards that cann't detect usb3320 and the Lan9514.
i doubt that it be the problem of soldering, Since OMAP4 is BGA packaging and usb3320 is QFN packaging, we cann't probe the pin of OMAP4 but can probe the pin of usb3320 using scope, so i plan to use a software-based method to test whether the ulpi signal of omap4 is physically connected usb3320. the method is describled below:
firstly, modify the usb driver of kernel to make it drive the the signal usbb1_ulpiphy_dat[7:0] to a constane value 1 or 0, and reverse it every 3 seconds.
secondly, use a scope to watch the corresponding pin of usb3320, if the signal changes every 3 seconds, then we can conclude that the usbb1_ulpiphy_data[7:0] is phycially connected to usb3320, thus no soldering problem exists.
and my question is:
how to modify the usb driver of kernel to drive the usbb1_ulpiphy_dat[7:0] to a constant value and change every 3 seconds?
thanks.