Arm-based microcontrollers

Arm-based microcontrollers forum

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Unlock PD7 and PF0

Bùi Thiên Ân

Prodigy 200 points

Hello
I'm a beginner and I have a issue:
I want to unlock PF0, the Datasheet shows me that I must write the value 0x4C4F434B to unlocks the GPIO Commit (GPIOCR)
register for write access.
I don't know why the value is 0x4C4F434B ? Where does that value come from ?

-----------------

Regards

Ân

over 9 years ago

0 Sai Reddy over 9 years ago

TI__Mastermind 22580 points

0x4C4F434B is a fixed key that is required to unlock the GPIO Commit register. The designers could have chosen any other value instead.

The reason this key is provided is prevent the code from unlocking these GPIOs by mistake.

Thanks,
Sai

0 Amit Ashara over 9 years ago

TI__Guru**** 244400 points

Hello Bui

0x4C4F434B is the ASCII hex value for LOCK

Regards
Amit

0 Bùi Thiên Ân over 9 years ago in reply to Amit Ashara

Prodigy 200 points

Hello Amit
If I was a designer, could I choose another value instead ?

0 Bùi Thiên Ân over 9 years ago in reply to Sai Reddy

Prodigy 200 points

thank you

0 Sai Reddy over 9 years ago in reply to Bùi Thiên Ân

TI__Mastermind 22580 points

Hello Bui,

This value cannot be changed any more (since the device/MCU is already designed and being manufactured).

Thanks,
Sai