MPD789322 Datasheet, PDF (30/96 Pages) NEC – 8-BIT SINGLE-CHIP MICROCONTROLLER

µPD789322,789324,789326,789327
(3) Subclock control register (CSS)
This register is used to specify whether the main system or subsystem clock oscillator is selected and to
indicate the operating status of the CPU clock.
CSS is set using a 1-bit or 8-bit memory manipulation instruction.
RESET input sets this register to 00H.
Figure 5-10. Format of Subclock Control Register
Symbol 7
6
5
4
3
2
1
0
Address After reset R/W
CSS
0
0
CLS CSS0
0
0
0
0
FFF2H
00H
R/W^Note
CLS
CPU clock operating status
0 Operating on the output of the (divided) main system clock
1 Operating on the output of the subsystem clock
CSS0
Selection of main system clock or subsystem clock oscillator
0 Main system clock oscillator (divided) output
1 Subsystem clock oscillator output
Note Bit 5 is read-only.
Caution Always set bits 0 to 3, 6, and 7 to 0.
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Preliminary Product Information U14673EJ1V0PM00