Figure 81. clock and power management unit connec, Figure 8-1), Figure 8-1 – Intel 386 User Manual

Page 183

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Intel386™ EX EMBEDDED MICROPROCESSOR USER’S MANUAL

8-2

Three of the internal peripherals have selectable clock sources.

The asynchronous serial I/O (SIO) unit can use either the SERCLK signal or an external
clock (connected to the COMCLK pin) as its clock source.

The synchronous serial I/O (SSIO) unit can use either the SERCLK signal or the PSCLK
signal.

The timer/counters can use either the PSCLK signal or an external clock connected to the
TMRCLKn input pin.

The individual peripheral chapters explain how to select the clock inputs.

Figure 8-1. Clock and Power Management Unit Connections

A2470-02

INT

(From ICU)

NMI

SMI#

RESET

Power

Management

IDLE

PWRDN

To WDT

PWRDOWN

(pin mux)

CLKPRS

Programmable

Divider

÷

2

Core

Buffer

Peripheral

Buffer

To Timer

To SIO0

To SIO1

To SSIO

To SSIO

To Peripherals

To Core

To Core

PSCLK

SERCLK

PH1C

PH2C

PH1P

To Peripherals

PH2P

÷

2

Processor Clock

PH1/PH2

PWRCON

CLK2

CLKOUT

Async Reset

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