Frequency Control Register (Fcon) - Oki ML63611 User Manual

ML63611 User's Manual
Chapter 5 Clock Generator Circuit (OSC)
5.6

Frequency Control Register (FCON)

FCON is a special function register (SFR) that selects the system clock.
FCON (062H)
RC oscillation/ceramic oscillation mode select
0: RC oscillation mode (initial value)
1: Ceramic oscillation mode
High-speed clock oscillation start/stop select
0: Oscillation stop (initial value)
1: Oscillation start
System clock select
0: Low-speed clock oscillation output (initial value)
1: High-speed clock oscillation output
bit 2: OSCSEL
This bit selects the RC oscillation mode or the ceramic oscillation mode of the high-speed clock
generator circuit. At system reset, this bit is cleared to "0", selecting the RC oscillation mode.
bit 1: ENOSC
This bit starts and stops oscillation of the high-speed clock generator circuit. At system reset, this
bit is cleared to "0", stopping oscillation of the high-speed clock generator circuit.
bit 0: CPUCLK
This bit selects the system clock, the basic operation clock of the CPU. At system reset, this bit is
cleared to "0", selecting output of the low-speed clock generator circuit (TBCCLK).
OPTION A (C): 1.5 V (3.0 V), Without regulator
circuit for LCD bias
bit 3

(R/W)
bit 2 bit 1
OSCSEL ENOSC
5 – 6
OPTION B (D): 1.5 V (3.0 V), With regulator
bit 0
CPUCLK
circuit for LCD bias