LC709006A

No.8265-11/14

Application Examples

(1) Example of a cascade configuration

Two or more LC709006A LSI chips can be cascaded to realize port expansion beyond 24 bits. Port expansion,

however, need to be made in units of 24 bits

× n (n denotes the number of LSI chips).

Fig. 5

(2) Variable port power level example

When controlling the level of I/O ports according to the power voltage level of the peripheral equipment, the user

can connect the output from the power supply of the peripheral equipment directly to the power supply pins for the

I/O ports. The LC709006A dispenses with the need to add an external level shifter circuit.

Note the following when configuring the LC709006A in this way:

Note 5:

• VDDP0: The voltage level of VDDP0 must not be higher than that of VDD (VDDP0≤VDD).

• VDDP1: The voltage level of VDDP1 must not be lower than that of VDD (VDDP1≥VDD).

• VDDP2: The voltage level of VDDP2 must not be lower than that of VDD (VDDP2≥VDD).

• The input level of all ports (P00 to P27) is dependent on the VDD power source; it depends on none of the power

sources VDDP0 to VDDP2.

* Be sure to check the electrical characteristics of the LC709006A.

Fig. 6

Microcontroller(MCU)

LC709006

3.3V

3.3V serial send/receive

2.5V parallel data I/O

5V parallel data I/O

Nch-open drain display

data output

2.5V peripheral

5V peripheral

LED display

2.5V

5V

5V

VDD

VSS, VSSP0, VSSP2

VSS

VDDP0

VDDP1

VDDP2

P00 to P07

P10 to P17

P20 to P27

RES, CE,

CLK, DIN, DOUT

0.1

μF

VDD

System Reset(RES)

Serial CS Output(CS)

Serial Data Output(SDO)

Serial Clock Output(SCK)

Serial Data Input(SDI)

Microcontroller(MCU)

RES

CS

DIN

CLK

DOUT

LC709006

RES

CS

DIN

CLK

DOUT

LC709006

RES

CS

DIN

CLK

DOUT

LC709006

System Reset

(LSI=1)

(LSI=2)

(LSI=n)

VDD