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MSP430 code read protection operation?

Hanson He
Intellectual 1485 points
Other Parts Discussed in Thread: MSP430F5418A

MSP430 Code read protection:
When burn program with JTAG fuse, whether BSL could erase program to restore MSP430 chip to its original state, then could re-use the JTAG function to debug program or simulation on CCS or IAR.
Whether have MSP430 chip Fuse bits repeat burn pipelining tools?

  • 0
    Guru 227245 points

    It's not exactly clear what you want to know...

    Older MSPs have a physical fuse that is irreversibly damaged by overcurrent. It permanently disables JTAG and has nothing to do with the flash content.

    Newer MSPs have a 'virtual' fuse. Ont eh power-on microcode, this fuse, which is part of the main flash or BSL flash (depends on device family), is checked and JTAG access is only enabled if the fuse is valid.
    Erasing flash through BSL will (at least where the fuse is part of main flash) re-enable JTAG access. Sicne the main flash content is gone then, this is not critical for code protection :)

  • 0 in reply to Jens-Michael Gross
    TI__Intellectual 1485 points

    Dear Michael, thx,

    How about MSP430F5418A? If we write its fuse, whether JTAG could access MSP430F5418A?

    If we need use JTAG to debug, whether we could use BSL erase flash, and then we could use JTAG access it again?

  • 0 in reply to Hanson He
    Guru 227245 points

    Teh 'fuse' is jsut a space in normal main flash. If it is 0xff or 0x00, the JTAG interface gets activated. If it contains something else, JTAG is disabled. So if you do a mass-erase of main flash through BSL, the JTAG will be re-enabled. And as long as you don't write something to this area, JTAG remains enabled. After writing something else to this area, JTAG will be disabled (or rather: not enabled, as it is off by default) after next power cycle.

  • 0 in reply to Jens-Michael Gross
    Guru 58965 points

    For MSP430F54xxA (as well as some other chips), the JTAG "Fuse" is not in the Main-Flash. It is in a somewhat hardware protected part of Flash. Thus Mass-Erase normally will not erase the JTAG "Fuse". The on-chip BSL code is in the same area too. This info is in the Data-sheet of the chip.

    Usually, BSL code resides at 0x01000 to 0x017FB and JTAG "Fuse" is at 0x017FC to 0x017FF.

  • 0 in reply to old_cow_yellow
    Guru 227245 points

    old_cow_yellow said:
    For MSP430F54xxA (as well as some other chips), the JTAG "Fuse" is not in the Main-Flash.

    You're right. The BSL password is. It's the FR57xx where the fuse in in main FRAM (it has no flash)

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