I'm experiencing what appears to be a hard processor hang on an i.MX353. If I write to the PORTSC1 register once, it works (does not hang), and I can read back what is written. If I write a second time to it (with the same value!), the CPU hangs. I have done this from uboot on the i.MX353 and it fails, but the same experiment on the MX35PDK 3stack evaluation board (an i.MX357) does not fail. Here's the sequence in uboot:
mw.l 0x53ff4184 0x1c000804 <---- this works
mw.l 0x53ff4184 0x1c000804 <---- this 2nd write HANGS
The same sequence typed into uboot on the MX35PDK evaluation board (iMX357) works just fine. You can write that register over and over and the processor does not hang.
Can anyone with a i.MX353 design out there please try these commands in uboot on your board and post the results here? Alternatively, can anyone shed light on why writing this value to PORTSC1 on an i.MX353 would cause the CPU to hang?