MPC5xxx中的主题 Re: MPC5748G

MPC5748G

2548903578 — Fri, 20 Mar 2020 11:38:11 GMT

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.

Re: MPC5748G

petervlna — Mon, 23 Mar 2020 10:11:47 GMT

Hi,

Well it is enough to set just 0x000000FC indeed.

Which will represents all modes enabled.

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

Re: MPC5748G

2548903578 — Tue, 31 Mar 2020 00:51:21 GMT

I already understand, thank you

Re: MPC5748G

cholland — Wed, 01 Apr 2020 20:12:44 GMT

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?

Re: MPC5748G

petervlna — Thu, 02 Apr 2020 10:27:36 GMT

No,

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

regards,

Peter