We are using the LogicPD AM3517 SOM-M2 module and it is failing to boot the first time. If we keep power on to the unit for a while and then reset, it will boot up properly. This is occurring in our board with our code and with the LogicPD eval board with the latest binary Uboot code downloaded from the TI website (Linux PSP SDK V05.02.00.00). Some modules will boot at room temperature, but fail to boot if the temperature is dropped to 50F. This problem does not exist with the LogicPD SOMAM3517-10-1780FJIR-A marked with part number 1016945 but only with the newer parts with number 1018006 rev A. Per LogicPD documentation, the NAND was changed to the Micron MT29F4G16ABBDAH4-IT:D (was MT29F4G16ABCHC), the SDRAM was changed to the Winbond W971GG6JB-25i (was Micron MT47H64M16HR) and the NAND transceiver was changed to the SN74AVCH24T245ZRGR which has bus hold (was SN74AVC24...). Uboot stops as shown below:
U-Boot 2010.06 (Oct 13 2011 - 14:08:27)
OMAP34xx/35xx-GP ES1.0, CPU-OPP2 L3-165MHz
AM3517EVM Board + LPDDR/NAND
I2C: i2c_init[128]: reached end of function
ready
RAM Configuration:
Bank #0: 80000000 256 MiB
Bank #1: 80000000 0 Bytes
start_armboot[299]:
NAND: HW ECC [Kernel/FS layout] selected
512 MiB
On the oscilloscope we see the CS0 (NAND) low for 420nS each cycle up to this point. After this point, the time has been changed to a 120nS cycle. Is the timing in the Uboot on the TI website correct for this new SOM module? If not, how do we change it in Uboot to relax the timing?