I am currently working on the BAF configuration. According to the MPC5746C Safety Manual, write access to the BAF region should be disabled by setting the PFLASH_PFCR3[BAF_DIS] bit, to prevent execution from non-safety-compliant code.
During debugging, I placed a breakpoint in the bootloader’s main() function and observed that the PFLASH_PFCR3[BAF_DIS] bit was already set (i.e., execution from the BAF region was disabled) before reaching this point.
Could you please confirm:
Does the BAF itself automatically set this bit before branching to the application’s start vector?
Or is it still recommended to explicitly configure PFLASH_PFCR3[BAF_DIS] = 1 in the bootloader application to comply with safety requirements?
Hello,
I have done the test.
I can see it is set by BAF itself once I have placed breakpoint on the read/write PFCR3 register.
Code stopped on entry to the register.
Best regards,
Peter
Hello,
write access to the BAF region should be disabled by setting the PFLASH_PFCR3[BAF_DIS] bit, to prevent execution from non-safety-compliant code.
disabling BAF execution in PFLASH control register3 (PFLASHC_PFCR3[BAF_DIS]
During debugging, I placed a breakpoint in the bootloader’s main() function and observed that the PFLASH_PFCR3[BAF_DIS] bit was already set (i.e., execution from the BAF region was disabled) before reaching this point.
Not execution. But access to the BAF flash region.
Could you please confirm:
Does the BAF itself automatically set this bit before branching to the application’s start vector?
I expect not as it is no documented. The default reset value is BAF_DIS=0. But I do not expect it since if it is set, BAF wont be able execute the branch to startup of application. It just makes no sense to have it set in BAF execution.
Or is it still recommended to explicitly configure PFLASH_PFCR3[BAF_DIS] = 1 in the bootloader application to comply with safety requirements?
Yes, it is recommended.
I would check where your SW is BAF_DIS setting by placing breakpoint on write to BAF_DIS in your debugger.
Best regards,
Peter
I placed a breakpoint in the startup file at the CPU0 entry point address (0xF8C010), which lies within the boot header section. Based on this observation, I assume that the PFLASHC_PFCR3[BAF_DIS] bit is being set by the Boot Assist Flash (BAF) itself before branching to the user application. Please confirm if this understanding is correct.
Hello,
I have done the test.
I can see it is set by BAF itself once I have placed breakpoint on the read/write PFCR3 register.
Code stopped on entry to the register.
Best regards,
Peter
