7721 datasheet(57/577 Pages) RENESAS

tên linh kiện	7721

Giải thích chi tiết về linh kiện	16-BIT SINGLE-CHIP MICROCOMPUTER

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CONNECTION WITH EXTERNAL DEVICES

3.3 Ready function

7721 Group User’s Manual

3–10

3.3 Ready function

Ready function provides the function to facilitate access to external devices that require long access time.

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The microcomputer enters Ready state by input of “L” level to the RDY pin and retains this state while the

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level of the RDY pin is at “L.” Table 3.3.1 lists the microcomputer’s state in Ready state.

In Ready state, the oscillator’s oscillation does not stop. Accordingly, the internal peripheral devices can

operate. Ready function is valid for the internal and external areas.

Table 3.3.1 Microcomputer’s state in Ready state

Item

Oscillation

φCPU, φ

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Pins A0 to A7, A8/D8 to A15/D15, A16/D0 to A23/D7, E, R/W,

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BHE, BLE, ST0, ST1, ALE

Pins P43 to P47, P5 to P10 (Note)

φ1

Watchdog timer

State

Operating

Stopped at “L”

Retain the state when Ready request was accepted.

Outputs clock

φ1.

Operating

Note: This applies when this functions as a programmable I/O port.

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