MSP430F6736: Security fuse gets automatically blown.

ugra narasimha

Part Number: MSP430F6736

Hi,

We are using MSP 430 FET UIF programmer & Lite FET-Pro430 Elprotronic s/w to program MSP4306736 MCU. For around 10% of the MCUs, we are facing blown security fuse issue, where we are unable to communicate with MCU.

Can this state be reversed? How?
Apart from manual triggering are there any other possibilities for triggering the fuse for example ESD(Electro Static Discharge). If yes how to detect the same & can it be due to high humidity.

Thanking you,

Ugra

over 8 years ago

0 zrno soli over 8 years ago

Guru 34983 points

Security JTAG fuse on MSP430F5xx/6xx devices is located at the end of the protected BSL area. It can be unblown by overwriting fuse value to 0 by using BSL. It is explained here... forum.43oh.com/.../

0 ugra narasimha over 8 years ago in reply to zrno soli

Intellectual 460 points

Thanks for replay zrno soli.

Apart from manual triggering from s/w are there any hardware or environmental conditions that might lead to fuse blow?

Best,

Ugra

0 James Evans over 8 years ago in reply to ugra narasimha

TI__Mastermind 49692 points

Hello Ugra,

As zrno soli (228909) correctly pointed out, the JTAG security fuse for the MSP430F5xx/6xx devices is considered a "soft-fuse" rather than the physical JTAG security fuse in the 1xx, 2xx, and 4xx families. These different types of memory protection mechanisms can be found in Table 11 in the MSP430 Programming With the JTAG Interface user's guide (SLAA320). With this in mind, I'm doubtful that a hardware event is locking this "soft-fuse". I'd be more concerned that your application code is changing/programming some value (that's not 0 or 0xFFFFFFFF) to the JTAG security lock key at the end of the BSL memory at addresses 0x17FC to 0x17FF.

Regards,

James

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MSP430F6736: Security fuse gets automatically blown.