GMS81508A Datasheet, PDF (21/91 Pages) Hynix Semiconductor – USERS MANUAL

HYUNDAI MicroElectronics
2.3. CLOCK GENERATION CIRCUIT
The clock generation circuit of GMS81508/16 consists of oscillation circuit, prescaler, Basic Interval
Timer.
The source clock of peripherals is provided by 11-bit prescaler.
OSC
Circuit
Clock Pulse Generator
Internal System Clock
Prescaler
ENPCK
MUX
8
B.I.T.(8)
BTCL
CKCTLR 0 1 2 3 4 5 6 7
IFBIT
W.D.T.(6)
6
Comparator
6
WDTR
WDTCL
IFWDT
6
To RESET
Circuit
Internal Data Bus
2.3.1. Oscillation Circuit
The clock signal incoming from crystal oscillator or ceramic resonator via Xin and Xout or from
external clock via Xin is supplied to Clock Pulse Generator and Prescaler.
The internal system clock for CPU is made by Clock Pulse Generator, and several peripheral clock
is divided by prescaler.
The clock generation circuit of crystal oscillator or ceramic resonator is shown in below.
Cout
Xout
Xout
Open
Xin
GND
Xin
External
Clock
Cin

Crystal Oscillator or Ceramic Resonator
 External clock
 In STOP Mode, The oscillation is stopped,
Xin pin goes to "L" level status, and Xout pin goes to "H" level state.
16