ATMEL AT91SAM9263

Hi,

1. We have designed and produced some ATMEL AT91SAM9263B-CU Microcontroller based SOM modules. These boards have SDRAM, NAND and NOR FLASH, Ethernet interface 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. We also have some boards where 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.

Sounds like the boards have been poorly manufactured or assembled.

Mike.

These are large complicated chips, 324-TFBGA package. I'm sure the board design to support them is complicated. I'm not sure how much help you are expecting basically saying they just don't work. There are literally hundreds of points of failure here. Check voltages, check connections, unfortunately unless you have an x-ray machine, not certain how you would check the bga solder points.