FRAM Boot Strap Loader (BSL) ROM or Flash based?

Lo said:

SYSBSLC is located at address 0x0182 according to the datasheet, but which bit is SYSBSLPE?

Indeed, the users guide is missing a description of the SYSBSLC register. It is unknown to me whether just the register description is missing or whether the BSL/JTAG fuse description if wrong and there is no such register anymore.
Given that it is an FRAM device, the second options seems more likely. i fear, this section about the bootloader has been just copied form the 5x family users guide.

Priya Thanigai said:

The FR57xx device has a ROM BSL.

That leaves the question open how the JTAG fuse is done. SInce it obviously isn't in teh BSL flash area (since there is no BSL flash area that could be programmed), where is it then? Is there a JTAG fuse at all?

Yes, this is also a part of the UG update that I was referring to.

The JTAG fuse exists and is in software similar to the F5xx devices.

Here is a sneak peek from the updated SYS chapter.

Regards,

Priya

A device can be protected from unauthorized access by restricting accessibility of JTAG commands that can be transferred to the device via the JTAG and SBW interface. This is achieved by programming the electronic fuse. Once the device is protected, the JTAG and SBW interface still remains functional, but JTAG commands that give direct access into the device are completely disabled. There are two ways to lock the device. Both of these require the programming of two signatures that reside in FRAM. JTAG Signature 1 (memory location 0FF80h) and JTAG Signature 2 (memory location 0FF82h) control the behavior of the device locking mechanism.

JTAG lock without password:

A device can be locked by writing 05555h to both JTAG Signature 1 and JTAG Signature 2. In this case, the JTAG and SBW interfaces will only grant access to a limited JTAG command set which restricts accessibility into the device. The only way to unlock the device in this case is to use the BSL to overwrite the JTAG signatures with anything other than 05555h or 0AAAAh.

 

Priya Thanigai said:

A device can be locked by writing 05555h to both JTAG Signature 1 and JTAG Signature 2. In this case, the JTAG and SBW interfaces will only grant access to a limited JTAG command set which restricts accessibility into the device. The only way to unlock the device in this case is to use the BSL to overwrite the JTAG signatures with anything other than 05555h or 0AAAAh.

Interesting. So you can just upload a program with the proper signature in the vector table to the MSP and upon next reboot, JTAG will be disabled. Nice for mass production - saves you an additional fuse-burning cycle.

Priya Thanigai said:

Yes, this is also a part of the UG update that I was referring to.

The JTAG fuse exists and is in software similar to the F5xx devices.

Here is a sneak peek from the updated SYS chapter.

Regards,

 Hi Priya, a doubt from datasheet and prior to check on silicon on 5xx parts:

 1> Jtag locked part can be restored to Jtag full access thru a BSL mass erase?

 2> BSL after jtag protection without enabling BSL is still accessible to do a mass erase of part?

 3> Fram devices behave different protection scheme or same as Flash?

 Regards

 Roberto

Roberto Romano said:

 1> Jtag locked part can be restored to Jtag full access thru a BSL mass erase?

Only on FR5xx devices, since the JTAG fuse is locate dinside the interrupt vector table and therefore subject to main memory programming and mass erase.

On F5xx devices, it is located in the BSL segment and NOT subject to mass erase operations.

Roberto Romano said:

 2> BSL after jtag protection without enabling BSL is still accessible to do a mass erase of part?

BSL is enabled by default. If you didn't disable it (if it is possible at all if the BSL is not writable), then of course the BSl won't run and therefore cannot perform any action.

Roberto Romano said:

 3> Fram devices behave different protection scheme or same as Flash?

Definitely. The FR5x are completely different from the F5x devices. In more than a few ways. And regarding write access the are totally different from all other MSPs.
I wish they had called them '7x' instead. The '5' is causing lots of confusions.

However, Priya is the FR-Lady here. But she's really busy.