7477 datasheet(242/361 Pages) RENESAS

Part #	7477

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

PDF	361 Pages

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Manufacturer	RENESAS [Renesas Technology Corp]

Direct Link	http://www.renesas.com

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242 / 361 page

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

2-16

APPLICATION

2.3 Timers

7470

7471

7477

7478

3 Pulse output mode: Piezoelectric buzzer output

Outline: The pulse output function of the timer is applied for a piezoelectric buzzer output.

Specifications: A square wave obtained by dividing the clock f(XIN) = 8 MHz into about 2 kHz is

output from the T0 pin. While the buzzer output stops, the level of the T0 pin is

fixed at “H.”

Figure 2.3.5 shows an example of a peripheral circuit. Figure 2.3.6 shows a connection of the timer

and setting of the division ratio. Figure 2.3.7 shows an example of control procedure.

Fig. 2.3.6 Connection of timer and setting of division ratio

Fig. 2.3.5 Example of a peripheral circuit [Pulse output mode]

,,,,

M3747x

While the piezoelectric buzzer output stops, the “H” level is output.

250

µs 250 µs

Set the division ratio so that the underflow period of

timer 1 may be equal to this value.

f(XIN)

8MHz

1/16

1/125

1/2

Timer 1

Fix

7477 Datasheet(PDF) 242 Page - Renesas Technology Corp