LPC MicrocontrollersのトピックRe: uid incrementation scheme

uid incrementation scheme

haukereese — Wed, 26 Oct 2022 15:02:11 GMT

Hi,

We are using some lpc11c24 devices on a CAN-Bus.

To differ the devices we're using the uid.

Based on historical reasons, we can only use 4 byte of the uid.

In the near past it happened that 2 devices had the same id.

So i wonder what is the scheme of the uid generation.

Is it just increment,

or has each fab has its own number region of the uid ?

Or is it just a random number generator ?.

What i need is to get an unique 4 byte id from this 128 bit uid.

best regards

hauke reese

Re: uid incrementation scheme

Miguel04 — Mon, 31 Oct 2022 14:56:58 GMT

Hi @haukereese

Which ID are you referring to? The CAN ID or the board ID?

The CAN ID is a value that you assign for the communication in your system, the board ID is saved on the registers and you cannot change it.

Best Regards, Miguel.

Re: uid incrementation scheme

haukereese — Tue, 01 Nov 2022 14:43:12 GMT

Hi Miguel,

I'm referring to the unique 128 bit chip ID (uid).

Best regards

hauke

Re: uid incrementation scheme

Miguel04 — Tue, 01 Nov 2022 17:18:50 GMT

Hi @haukereese

In which register are you reading the ID? the Device ID register (0x4004 83F4) has a size of 32 bits, not 128 and the value depends on the device.

Miguel.

Re: uid incrementation scheme

haukereese — Wed, 02 Nov 2022 09:48:12 GMT

Hm,

I'm using the IAP command 58 to get the UID.

There the result is 4*32-Bit registers.

You can find it in the user manual UM10398 on page 445.

Re: uid incrementation scheme

haukereese — Wed, 02 Nov 2022 09:54:09 GMT

Hi Miguel,

this is the id for the device family.

For example each lpc11c24 with the same package have the same ID.

What i need is the unique part id to differ between 2 lpc11c24 devices.

Best regards

hauke

Re: uid incrementation scheme

haukereese — Thu, 03 Nov 2022 14:10:12 GMT

No one an idea, how to get an individual 32 Bit id from this 128 Bit id ?

best regards

hauke reese

Re: uid incrementation scheme

Miguel04 — Mon, 07 Nov 2022 15:33:44 GMT

Hi @haukereese

Sorry for the misunderstanding, you are correct the ReadUID returns a 128 bit value, you could use this 128 bit value to differentiate the LPCs since choosing only 32 bits does not guarantees they are going to be unique. Let me know if you have another question.

Miguel.