Why were references to the STM32L051C8 RNG peripheral removed?

[DAlbe.3]

In some ST documents the STM32L0X1 is listed as having an RNG peripheral and older versions of the CMSIS headers list the RNG register addresses. Moreover, enabling the peripheral and using it appears to generate random numbers. However newer manuals and CMSIS headers appear to have removed references to the RNG. What's the situation?

[Tesla DeLorean]

I've got a couple of docs where I'd say this is ambiguously / broadly stated, or internally inconsistent. The intractable numbering methodology leads to a lot of confusion, and miss / over statement of functionality.

I have this in docs from 2014 and 2016

I don't find any DS or RM for the "Access Line" parts indicating T-RNG

[DAlbe.3]

As I mentioned in my response to Amel, the STM32L05x is specifically called out in the App Note that discusses RNG (AN4230). In that app note, where they wish to refer to specific sub-components rather than a family, they spell them out rather than using the 'x'. For example:

STM32L0 Series STM32L05x, STM32L06x, STM32L072/073

(note that it doesn't say: STM32L07x)

It doesn't matter at this point, Amel and Peter have answered my question: the ST32L051 does not contain the RNG peripheral, or at least cannot be relied on to contain it. Unfortunately for us, the components used in our prototypes and pilot production appear to contain the peripheral, but as Peter described, this is likely a case of packaging/labeling 052 wafer parts as 051: perfectly legitimate, but not something that can be counted on for subsequent production runs.

[Tesla DeLorean]

The die should be identifiable via the DEVID in the DBGMCU of most STM32

And probably the UNIQUE ID, but that's not well/publicly documented

[DAlbe.3]

Thanks @Community member​, the device and rev ID indicate what I'd expect for an STM32L051: 0x417=category 3, 0x1038=Rev X. I make use of the UID routinely as a device identifier, but I'm not sure how to decode the fields beyond what the RM indicates: wafer, lot, and I suspect the remainder is X,Y location of the die on the wafer...but how to map that to a product ID? If you know, please share!

[Simon V.]

Hello Dalbe,

The UID register do not include the device ID. UID register includes only wafer, lot and device X/Y coordinates.

We recommend you to use a dedicated constant in your firmware depending on the product to be programmed.

During the device programming process, by script you may set the constant value to match the mount pcb on your pcb

Sorry for the inconvenient

Regards,

Simon