How to tell the difference between Rabbit 4000, 5000 and 6000?

The Rabbits have the GCPU and GREV registers. they allow to easily identify Rabbit 2000 and Rabbit 3000 variants (GCPU for the Rabbit 2000 vs. 3000, GCREV for the revision).

However, according to the user manuals, the Rabbit 4000, 5000 and 6000 all have the exactly same value in both registers.

GCPU bits 4:0, per the manuals I’m looking at:

2000: 00000
3000: 00001
4000: 00010
5000: 00011
6000: 00100

I believe there is a typo in the description in the 5000 and 6000 manuals for those bits in GREV – they are still the “Revision identifier for this version of the chip.” (as shown in the manual I’m referencing for Rabbit 4000) and will vary with each revision (A, B, C) of a given processor.

Rabbit 4000 Microprocessor: https://www.digi.com/resources/documentation/digidocs/PDFs/019-0152_N.pdf

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Thanks. I’ve now had another look at the manuals.

E.g. the Rabbit 6000 User manual for GCPU indeed states 4, value you gave, in the section 4.4. However, according to section 4.1.2, which I was looking at, the value is 2.