ATMEL AT91SAM9263以什么方式调试？

嗨，1。在模块上设计并制作了一些ATMEL AT91SAM9263B-CU微控制器系统。这些板有SDRAM，NAND和NOR闪存，以太网接口等，其中一些确实启动，我们可以通过USB访问板。一些板没有启动，USB没有被主机识别。当我们检查硬件时，我们发现ATMEL控制器上的复位信号（NRST）总是“低”（0）。我们还有2个晶体（16MHz，32.768 kHz）与处理器连接，不显示任何输出。帮助我们以什么方式调试？2。在多个模块中，我们观察到复位信号是OK（切换高到低和低到高），但是主机上的USB接口没有被PC主机识别。请帮助。



      以下为原文

    Hi,

1. We have designed and produced some ATMEL AT91SAM9263B-CU Microcontroller based System-On-modules.  These boards have SDRAM, NAND and NOR FLASH, Ethernet interfaces etc.,
Of which some did boot and we could access the board via USB. Some of the boards are not booting and the USB is not recognized by the host.
When we checked the hardware we find that the reset signal (NRST) on the Atmel controller is always "LOW" (0).
Also we have 2 crystals (16MHz, 32.768KHz) interfaced with processor which does not show any output.  
Can someone help us in what way can we debug?

2. In few modules, we observed that the reset signal is OK (toggles high to low and low to high), but the USB interface on board is not recognized by the PC host.
Please help.