Hi

I saw the datasheet but I don't understand (also )how work it.

at parallel port frequency modulaion mode,

the terms are

1.FTW reg.(32bit)

2.parallel port value(16bit) (PAR)

3.offset (FMGAIN)

4. finally used TUNING VALUE for Frequency gen.(TV) 32bit

I think that TV is calculated like below,

TV = FTW + ( PAR << FMGAIN );

here, first my question, the equation is right ?

and, PAR is unsigned value, so Is center frequency determined with the half of MAX-PAR value?

Thanks for your help

I think the answer to both of your questions is "Yes".

Stated differently, the output frequency is:

TV = FTW + PAR*(2^FMGAIN)

The center frequency (TVc), is the average of the min. and max. TV value, where:

TVmin = FTW + PARmin*(2^FMGAIN)

TVmax = FTW + PARmax*(2^FMGAIN)

Therefore, TVc = (TVmin + TVmax)/2, which gives:

TVc = FTW + (PARmax + PARmin)*[2^(FMGAIN - 1)]

For the special case of PARmin = 0 and PARmax = 2^16 - 1:

TVc = FTW + (2^16 - 1)*[2^(FMGAIN - 1)], or, in expanded form:

TVc = FTW + 2^(FMGAIN + 15) - 2^(FMGAIN - 1)