NEC PD17062 Datasheet page 222

Mos integrated circuit 4-bit single-chip microcontroller containing pll frequency synthesizer and image display controller
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18.3.2 Programmable Divider (PD) and Data Buffer (DBF)
The programmable divider divides the frequency of an input signal at the VCO pin by the values specified
in the swallow counter and programmable counter.
The swallow and programmable counters consist of a 4- and 12-bit binary downcounter, respectively.
The swallow and programmable counters are loaded with a division value by setting it in the PLL data
register (PLLR, at address 41H) through the data buffer (DBF).
Writing to and reading from the PLL data register are performed with the "PUT PLLR,DBF" and "GET
DBF,PLLR" instructions respectively.
A division value is called an N-value.
The following expression represents the frequency "f
using the value N in the PLL data register (PLLR).
Pulse swallow method
f
in
f
=
(where N is 16 bits)
N
N
See Section 18.7 for how to set the division value (N-value) for each frequency division method.
222
" of a signal generated in the programmable divider
N
PD17062

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