Determining how the processor was reset (t104x)

[mattweber]

Had a question come up related to determining how the processor was reset.  Is there any internal bookkeeping that would allow me to see if a POR caused my reset compared to a hard reset?  We're using an external watchdog what doesn't contain any state information that we can utilize to determine how we reset.

I haven't had any luck finding this in the documentation yet in the TRM.  I figured it wouldn't be in the e5500 arch manual as it seemed to be more specific to the overall processor.

[lunminliang]

To check if a reset is caused by POR or hard reset, please use Core Reset Status Register (DCFG_CCSR_CRSTSR)

A power-on reset of the device causes the following to occur:

• RST_PORST is set

• All other bits are cleared

A hard reset of the device causes the following to occur:

• RST_PORST remains unchanged (PORST resources are not affected by Hard Reset)

• RST_HRST is set

• All other bits are cleared

See Section 7.3.23 in T1040RM.pdf for this.