unique ID of NXP Microcontrollers

[gunnarbohlen]

Hello,

we use the LPC54618 for several projects. One project uses CANopen which requires a 32bit serial number for each device,  another project uses J1939 which requires a 21bit unique number.

Is is possible to derive shorter unique numbers from the build-in 128bit unique Id, which is already present in the CPU?
Is the unique id in LPC54618 only "unique" for this type of LPCxxxxx CPU, or is it "unique" for all NXP CPU's?
Is a unique id an arbitrary 128bit number, or is it possible to "decode" a unique ID to get information about the device (cpu type, ..)

Regards, Gunnar Bohlen

[Alice_Yang]

Hello gunnarbohlen,

Is is possible to derive shorter unique numbers from the build-in 128bit unique Id, which is already present in the CPU?

-> You can use a function to reduce the length, for example Hash Algorithm.

Is the unique id in LPC54618 only "unique" for this type of LPCxxxxx CPU, or is it "unique" for all NXP CPU's?

-> I'm not very sure about this, I guess it is unique for LPC54xxx serial .

Is a unique id an arbitrary 128bit number, or is it possible to "decode" a unique ID to get information about the device (cpu type, ..)

-> It is arbitrary. 

BR

Alice

[gunnarbohlen]

Hello , thank you for the answer.

I'm not confident that there is a hash function which can reduce a 128bit number into a unique 21 bit number. Could you give me an example?

We need either a 21 bit or 32 bit unique number for our devices, therfore I assume we need to program one into each device and cannot use the unique id of the chip.

Could you please tell me a contact persion who knows whether the unique id is only unique for LPC54xxx, or whether is it unique for a broader range of NXP CPU's?
This is important for us because we need to know if in our database the unique id identifies one product (which may contain different types of NXP CPU's) of if we need to check the  CPU-Type as well.

Thank you, Regards,

Gunnar Bohlen

[converse]

> I'm not confident that there is a hash function which can reduce a 128bit number into a unique 21 bit number. Could you give me an example?

That is impossible - you cannot hash 2^128 into a unique 2^21 number. or even 2^32 - you still have 107 or 96 bits of missing information!

> We need either a 21 bit or 32 bit unique number for our devices, therfore I assume we need to program one into each device and cannot use the unique id of the chip.

Correct. If you need to be unique, the only way you can control this is to do it yourself.

As I understand it the NXP unique ID is "Universally Unique" - but you need all 128 bits. Search UUID for more info.