FlexTimer: FTMEN=0

[xarowubas]

Reference manual: K60P144M100SF2V2RM

From the reference manual of the K60:

" The second set, from FTM_CNTIN to FTM_PWMLOAD registers, has the FTM specific
registers. Any second set registers, or bits within these registers, that are used by an
unavailable function in the FTM configuration remain in the memory map and in the
reset value, so they have no active function."

" Do not write to the FTM specific registers (second set registers) when FTMEN = 0."

FTMEN itself is in register MODE, which is a second set register. Hence, FTMEN could never be set to 1 ...

So, I assume the reference is inexact concerning what is writable with FTMEN=0, in general.

1. For some fields in the second set registers is explicitly mentioned, that they are only usable with FTMEN=1.

What is about the others like CNTINIT, ...?

2. If FTMEN=0 is set, how do they behave, e.g., is it treated like CNTINIT=0, no matter what CNTINIT was set last time FTMEN=1 was true? What is about write protection, is it disabled with FTMEN=0?

[kerryzhou]

Hi Xaro Wubas,

    

     The above description means the FTM in K60 have two functions, one is the basic TPM function(FTMEN=0), which just have the register FTM_SC to FTM_C7V registers, other register can't be controlled; Another is the advanced function(FTMEN=1), which have all the register FTM_SC to FTM_PWMLOAD.

     So, you can treat the FTMEN as a gate control bit, it used to select the TPM basic function or the advanced FTM function.

     Now answer your two question:

1. For some fields in the second set registers is explicitly mentioned, that they are only usable with FTMEN=1.What is about the others like CNTINIT, ...?

Answer: Just FTMEN is special, FTMEN is a gate control bit. CNTIN is used under FTMEN=1.

2. If FTMEN=0 is set, how do they behave, e.g., is it treated like CNTINIT=0, no matter what CNTINIT was set last time FTMEN=1 was true? What is about write protection, is it disabled with FTMEN=0?

Answer: Yes, when FTEMEN=0, the other register from FTM_CNTIN to FTM_PWMLOAD regiser won't function, so it's better don't write it.

Wish it helps you!

If you still have question about, please kindly let me know.

Have a great day,
Kerry

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