SM8521 Datasheet, PDF (18/56 Pages) Sharp Electrionic Components – 8-Bit Single-Chip Microcomputer

SM8521
SYSTEM CONTROL
Oscillator Circuit
The SM8521 is built-in the main-clock and sub-
clock oscillator circuits for generating clock signal.
The main-clock oscillator circuit is applied to 1.5 to
10 MHz. The sub-clock oscillator circuit is applied
to 32.768 kHz.
Clock System
The SM8521 uses the main-clock and sub-clock
oscillator circuits to generate the required clock.
The system clock, leads CPU operation, is one of
the five clocks which divides the main-clock (fCK)
into 1/2, 1/4, 1/8, 1/16 and 1/32. It also selects
from sub-clock (f32K). In addition, the clocks
supplied to the peripheral functions are fc1-fc10
divided by the prescaler PRS0 and derived from
the 1/2 clock of main-clock (fCK/2), and fx1-fx8 divided
by the prescaler PRS1 and derived from the sub-
clock.
fCK = 11.0592 MHz
CKIN
CKOUT
Main-clock
fCK _1/2
generator circuit
System clock
frequency control
System clock
CG
SM85CPU
Warming up counter
fc10
Prescaler PRS0
fCK/2
fc1-fc10
OSCIN
OSCOUT
Function blocks
operation
RAM register
read/write
Peripheral functions
Interrupt control
f32K
Sub-clock
f32K
generator circuit
f32K = 32.768 kHz
Prescaler PRS1
Fig. 7 SM8521 Clock System
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