Reading register bits - help

[FreshmanNewbie]

I am using this device, and this is the errata document.

I was to disable Auto-MDIX.
Hence, I went to this register, page 127, section 5.2.2.20 PHY Auto MDI / MDI-X Register.

When I went to understand, how to write to this register, I found on page 65 of the datasheet. "For multi-byte registers, the data is addressed in a big-endian format, with the most significant byte at the lowestaddress, and the least significant byte at the highest address,"

Also, with reference to the errata document point 6, I need to write this register as 32bit along with the 5.2.2.21. register PHY Control Register.

Upon default configuration start-up, I got these values for the 5.2.2.20 & 5.2.2.21 REGISTERs - 0x2400 0000.
While I tried to decode the above register values for each bit by big endian format as they mention. But when I do so, it seems that "RESERVED" bits are having some value. But RESERVED Bits should not have any value right? Hence, I assume, I am reading it incorrectly. Please clarify.

I am not able to understand how this value is coming?

Can someone help me to understand the default registers value that I obtained above? And with the same thing, I just want to disable MDIX. Hence, what should be the change I need to do?

 

[KlausST]

But RESERVED Bits should not have any value right?

a bit is a digital information with two states: HIGH /LOW or ON/OFF or 1/0.
--> there is no "No value". It still will be 1/0 .. but the value may have no meaning.

And: the datasheet even tells you the "default" state of these bits.

*****

Also, with reference to the errata document point 6, I need to write this register as 32bit along with the 5.2.2.21. register PHY Control Register.

But the document says:
"Certain PHY registers must be written as pairs instead of singly".
This means a pair of 16 bits, but not a single 32 bit.

You buy a pair of shoes, and not a single "item" of two shoes glued together.
*****

So to be able to help you ..
* we need to see your code
* we need to know your expectation

Klaus