1 idle mode, Figure 86. timing diagram, entering and leaving i – Intel 386 User Manual

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8-9

CLOCK AND POWER MANAGEMENT UNIT

8.3.1

Idle Mode

Idle mode freezes the core clocks (PH1C low and PH2C) high, and leaves the peripheral clocks
(PH1P and PH2P) toggling. To enter idle mode:

1.

Program the PWRCON register (Figure 8-5).

2.

Execute a HALT instruction.

3.

The CPU enters idle mode when READY# terminates the halt bus cycle.

NOTE

CLKOUT continues to run while the CPU is in idle mode.

Figure 8-6. Timing Diagram, Entering and Leaving Idle Mode

A2468-02

CLK2

PH2C

PH1

PH2

?

PH1C

CLKOUT/PH1P

?

PH2P

CLK2

PH2C

PH2

PH1

PH2

PH1C

CLKOUT/PH1P

PH1

PH2P