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TMS320F280039C: Boot mode Configuration.

Dikshith Poojary
Prodigy 80 points

Part Number: TMS320F28P550SJ9

Tool/software:

Part number for TMS320F28P550SJ9 was not available as option so i have used TMS320F280039C as thread title 

this question is for TMS320F28P550SJ9 

According to TRM, 
Default Boot Modes are done by the default boot mode select pins.



But before checking this GPIO's it reads the OTP_BOOTPIN_CONFIG_KEY 

What are the GPIO states before the BOOT mode flow starts ??

If the key is 0x5A it checks BOOTPINCONFIG , BOOTDEF for Custom Boot Modes

My Question is when a fresh out if factory microcontroller is powered ON, all the BOOTPINCONFIG-OTP sections are 0xFFFF and since the GPIO's are floating what will be the CPU default boot mode be ?? 



If the CPU mode is FLASH, what will be the default FLASH ENTRY POINT (ADDRESS)?
According to datasheet,

But this case the BOOTDEF values are all 0xFFFF??
what will happen in this condition?

this case is for Standalone boot flow (Since no Debugger is connected) and here there is no jump to Wait boot for invalid Boot mode key (as per the Flow diagram in TRM).

  • 0
    TI__Guru* 77510 points

    If the default boot pins are left floating, then there is no way to guarantee which boot mode will be selected(since internal PUs are also disabled from the factory by default).  It is the requirement of the PCB to control these pins on power up so that the state can be sampled by the BROM and the appropriate boot mode can be selected.

    For the non-flash bootloaders, I believe they will just wait for comms to happen.  For flash boot, code will jump to flash entry point, encounter illegal instruction, and then branch to default ISR...eventually I believe that watchdog will time out and part will reset itself.

    Best,

    Matthew