Integrated Circuits Inc.

aMTP777

MAY 10, 2011

7

5V CPU Control with COUT

Note for COUT speaker drive:

1. C1 and C2 must be connected as close to the VDD/VDDA and VSS/VSSA pins as possible.

2. Rb is base resistor from 120 Ohm to 390 Ohm depends on value of VDD and transistor gain.

3. Tr is an NPN transistor with beta larger than 150, e.g. 8050D.

4. Rosc = 220K Ohm with Vdd=3.0V can support sampling rate up to 14KHz.

VSS, VSSA

RSTB

PB3

OSC

0.1uF

220K

Tr

VOUT2_

COUT

8

1/4W

Speaker

HT7335

PB0

PB1

PB2

VOUT=+3.5V

Addr[0]

Addr[1]

Addr[2]

IO0

VIN=+5V

Note :

PB0 to PB2 set to internal pull-up

Addr[0] to [2] are open drain output drive

Rb

4.7K

VDDA

C1, 0.1uF

Rp=1ohm

VDD

C2, 0.1uF

DAT

SCK

DO

EN