MPC5748G

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MPC5748G

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2548903578
Contributor III

I don't quite understand the ME_RUN_PC0..7 register when using MPC5748G. The routine given on the official website is to enable ME_RUN_PC0 = 0x000000fe to enable all modes, but when I look at this register, why are 0-23 bits reserved? Doesn't it make sense to write the lower eight bits? Anyone explain it, thank you very much.

4 Replies

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petervlna
NXP TechSupport
NXP TechSupport

Hi,

Well it is enough to set just 0x000000FC indeed.

Which will represents all modes enabled.

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Doesn't it make sense to write the lower eight bits? Anyone explain it, thank you very much.

By writing 0x000000FC you will write the bits 24 to 29.

I do not understand where do you see the issue?

regards,

Peter

688 Views
cholland
Contributor V

I often wondered that myself.

Your writing to register bits that are "read only".

The same goal could have been accomplished with a write of just 0xFC.

In this particular case, the bits are '0' and perhaps it does not matter, which is what I am assuming.

I wonder about cases where the bits are reserved? Would wringing to those bits matter?

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petervlna
NXP TechSupport
NXP TechSupport

No,

once the bits are read only you cant write to them, The write will be ignored.

regards,

Peter

688 Views
2548903578
Contributor III

I already understand, thank you

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