7540 datasheet(215/366 Pages) RENESAS

Part #	7540

Description	8-BIT CISC SINGLE-CHIP MICROCOMPUTER 740 FAMILY / 740 SERIES

PDF	366 Pages

Scroll/Zoom	100%

Manufacturer	RENESAS [Renesas Technology Corp]

Direct Link	http://www.renesas.com

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215 / 366 page

2-139

REJ09B0018-0200Z

Rev.2.00

Jun 21, 2004

7540 Group

APPLICATION

2.9 Reset

2.9.4 Oscillation stop detection circuit

The oscillation stop detection circuit can be used to detect the stop by some failure or disconnection of

an external ceramic oscillation circuit.

In this section, the setting method and application example.

(1) Operation description

When the stop of an external oscillation circuit is detected by the oscillation stop detection circuit,

the oscillation stop detection status bit of MISRG is set to “1” and the internal reset occurs.

The 7540 Group starts operation by the on-chip oscillator after system is released from reset.

Accordingly, error of the external oscillation circuit can be detected by checking the oscillation stop

detection status bit after system starts operation.

Notes 1: When the stop mode is used, set the oscillation stop detection function to “invalid”.

2: When f(XIN) oscillation is stopped, set the oscillation stop detection function to “invalid”.

7540 Datasheet(PDF) 215 Page - Renesas Technology Corp