Samsung KS57C2308 manual Clock Output Circuit, Clock Output Procedure

KS57C2308/P2308/C2316/P2316 OSCILLATOR CIRCUITS

CLOCK OUTPUT CIRCUIT

The clock output circuit, used to output clock pulses to the CLO pin, has the following components:

—4-bit clock output mode register (CLMOD)

—Clock selector

—Port mode flag

—CLO output pin (P2.2)

CLMOD.3
CLMOD.2
4
CLMOD.1	Clock	CLO
CLMOD.0	Selector
	P2.2 OUTPUT LATCH	PM 2
	clocks
(fxx/8, fxx/16, fxx/64, CPU clock)

Figure 6-7. CLO Output Pin Circuit Diagram

CLOCK OUTPUT PROCEDURE

The procedure for outputting clock pulses to the CLO pin may be summarized as follows:

1.Disable clock output by clearing CLMOD.3 to logic zero.

2.Set the clock output frequency (CLMOD.1, CLMOD.0).

3.Load "0" to the output latch of the CLO pin (P2.2).

4.Set the P2.2 mode flag (PM2) to output mode.

5.Enable clock output by setting CLMOD.3 to logic one.

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