Hello,
I am debugging some problem boards that are behaving in a peculiar manner. The design uses the MPC8308. These boards are peculiar in that they hang upon power up but will boot normally after a manual reset is applied. There are other builds of this design that boot fine at power up. The two problem boards hang in the same place. I have investigated the power sequencing (Core Voltage before I/O voltages, Looks good, Supply ramp time is 14ms, shortened it to 1.6ms no change), the reset logic (PORESET released 214ms after power-up and clocks have been running), I can power the board while holding the MPC8308 with a manual PORESET, wait minutes and release the manual PORESET signal and the board hangs in the same spot. We are running U-BOOT with a Linux Kernel, but it is hanging somewhere in U-BOOT just after initializing the eTSECs. Both builds that hang, have the same processors and are as follows: [MPC8308VMAGD, 400/266 MHz, CTQLW1208, 00M17Y WDAJCTG] There is a later revision processor, MPC8308VMAGDA. But I'm finding it difficult to discover the differences in the Revisions. Thanks for any suggestions.
I think its time to connect debugger and start debugging, where exactly the code execution hangs, at which particular instruction, what this instruction is exactly doing in this pace of code, and why it fails.