7477 datasheet(281/354 Pages) RENESAS

Part #	7477

Description	8-BIT SINGLE-CHIP MICROCOMPUTER 740 FAMILY / 7470 SERIES

PDF	354 Pages

Scroll/Zoom	100%

Manufacturer	RENESAS [Renesas Technology Corp]

Direct Link	http://www.renesas.com

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281 / 354 page

7470/7471/7477/7478 GROUP USER’S MANUAL

2-46

APPLICATION

2.8 Low-power dissipation function

7470

7471

7477

7478

Fig. 2.8.5 Example of control procedure [Low speed mode

→ Ordinary mode]

(4) Low speed mode

→ Ordinary mode

Specifications: The system clock is switched from the sub-clock (f(XCIN) = 32 kHz) to the main

clock (f(XIN) = 8 MHz). The sub-clock is stopped.

Figure 2.8.5 shows an example of control procedure.

Set the CPU mode register

! 0

01 1 !

0 CPUM (Address 00FB16)

Fixed to “0”

XCIN, XCOUT selected

XCOUT drive capacity High power selected

Main clock oscillation

System clock Low-speed mode selected

Wait f(XIN) oscillation stabilizing time

T For certain time, ask the oscillator manufacturer.

Set the CPU mode register

! 0

0 ! 0 !

0 CPUM (Address 00FB16)

Fixed to “0”

P50, P51 selected

Main clock oscillation

System clock Ordinary mode selected

7477 Datasheet(PDF) 281 Page - Renesas Technology Corp