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disabling JTAG - readout protection

developer2
Senior
Posted on June 19, 2013 at 19:29

Hi all,

is there a way how to definitely disable JTAG ?

so it will be not usable anymore ?

i'm scared of flash code steal (of course when Read-out protection enabled) ...

Kind regards,
3 REPLIES 3
Posted on June 19, 2013 at 19:59

For which device? The F2 and F4 have

''�? Level 2: Disable debug/chip read protection

 

When the read protection Level 2 is activated by writing 0xCC to the RDP option byte, all protections provided by Level 1 are active, system memory and all debug features (CPU JTAG and single-wire) are disabled when booting from SRAM or from system memory, and user options can no longer be changed.

 

 

Memory read protection Level 2 is an irreversible operation. When Level 2 is activated, the level of protection cannot be decreased to Level 0 or Level 1.

 

 

Note: The JTAG port is permanently disabled when Level 2 is active (acting as a JTAG fuse). As a consequence, boundary scan cannot be performed. STMicroelectronics is not able to perform analysis on defective parts on which the Level 2 protection has been set.''

Which I suppose will protect you from the guys with the JTAG pods, but not so much the industrialist with the FNA and SEM.

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developer2
Senior
Posted on June 19, 2013 at 20:06

well, Thank You Clive,

i'm developing on STM32F103 :(

but i should switch to STM32F4XX to be safer  :(

and what you mean by FNA or SEM ?

Posted on June 19, 2013 at 20:39

On the F1 you can remap/disable the JTAG/SWD in your code, BOOT0 can remedy that, but RDP is also checked in the System Loader.

I guess you could also cut off the pins too, or otherwise limit physical access.

Strong HNO3,... Consider whom you are protecting your IP from, and the techniques they might employ to get access to it.

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