NEC 78K0S/K 1+ Series Application Note page 11

[Example 3] A crystal or ceramic oscillation clock is used, used as the P34 pin, the low-speed internal oscillator can
be stopped, and the oscillation stabilization time is minimized (2
(This is the same as in Example 2, except for the underlined part.)
Address: 0080H
1 0 0 1
The option byte setting value is
together with the protect byte setting, the following results.
OPBT CSEG
DB
DB
CHAPTER 4 SETTING METHODS
0 0 0
"10010000 (bits 4 and 7 must be set to 1)". When the software is described
AT 0080H
10010000B
11111111B
Application Note U18752EJ2V0AN
10
/f ).
x
0
Control of low-speed internal oscillator oscillation
Oscillation is stopped by software setting
0
(LSRSTOP bit is set to 1).
Selection of system clock source
0 0 Crystal or ceramic oscillation clock (10 MHz (MAX.))
Selection of P34/RESET pin function
0 Used as a P34 pin.
Specification of oscillation stabilization time on power
application or after reset release
10
0 0 2 /fx
11