MSP430F5229: How to check if JTAG interface of MSP430F5229 is locked

Hi Xin,

When you say some random data has been loaded, I think this could potentially be the problem. Where do you load data - does it include the BSL area of memory? If so, if addresses 0x17FC-FF are programmed with anything other than 0xFFFF or 0x0000 then the JTAG is locked. So if you filled the BSL area of flash with random data, then the device would be locked because the BSL area of flash is from 0x1000-1800 and includes those addresses.

Even if you do not write to the BSL area, you could make the device inaccessible by filling it with random values, depending on what they are - if the device starts up and tries to execute code but it's really random values that it is interpreting as code, depending on what the values are you could have erratic code execution leading to constant resets such that the device is not accessible via JTAG even though the JTAG is not locked.

A safer way to test would be to load a real code image like blinky, and then append the random values. That way there is valid code preventing erratic execution, but you can still fill the memory (make sure to leave 0x17FC-17ff alone if you test programming BSL flash).

Or, if you want to keep as much randomness as possible, you could choose an address, e.g. the first address of the flash, and load that with 0x3FFF because that corresponds to jmp$ or loop in place. Then, load 0xFFFE with the value of this address (e.g. first address of flash). Then everything else could be random. The reason to do this is so that on a reset, the device checks the reset vector at 0xFFFE to see where to start executing code - it jumps to that address of flash, and then would see the jmp$ instruction or loop-in-place, and just stay there forever, preventing erratic code execution.

I hope this helps.
Regards,
Katie