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PT8300 V1.8

- 4 -

February, 2006

16-Bit I/O Expander IC

PT8300

FUNCTION DESCRIPTION

PT8300 is an I/O Expander IC which independently generates a 16-bit serial input-to-parallel output

shift register and a parallel input-to-serial output shift register for the purpose of reading the serial input

data that is generated during the parallel to serial data output conversion.

When the /RESET Pin is connected to VSS, the outputs of pins -- P0 to P7 are 0. If the PULLUP pin is

connected to VSS or open, the outputs of pins -- P8 to P15 are floating. If the PULLUP pin is connected

to VDD, the P8 to P15 pins are 1.

NO USED PINS

If any of the Input, Output or I/O (P8 to P15) pins are not used, then the following conditions listed in the

table must be carefully followed.

When an output pin is not used, it must keep OPEN. The unused input pin must only be set to either

HIGH or LOW. It should be noted that when an input pin is not used, it cannot be OPEN.

When the I/O Pins -- P8 to P15 -- are not used, certain conditions must be followed. If any of these pins,

P8 to P15 are connected to VSS, the PULLUP Pin must also be connected to VSS. If any of these pins

-- P8 to P15 -- are connected to VDD, then the Internal Shift Register 1 (Q8 to Q15) must be set to 1. If

these pins -- P8 to P15 -- are not connected to either VSS or VDD, then any one of the following

conditions must be followed:

1) PULLUP pin must be connected to VDD and the Shift Register 1 (Q8 to Q15) must be set to 1, or

2) PULLUP pin must be connected to VSS and the Shift Register 1 (Q8 to Q15) must be set to 0.

It must be noted that when P8 to P15 are not in used, they must be set to HIGH or LOW.

Type of Pin Not Used

Condition

Output pin

The unused output pin must be kept OPEN or not connected

Input pin

The unused input pin must either be set to HIGH or LOW.

It cannot be kept OPEN.

Connected to VSS

PULLUP pin must be connected to VSS

Connected to VDD

Shift register 1 (Q1 to Q15) is set to 1

I/O pin (P8 to P15)

No Connection

Any one of the conditions must be followed:

1. PULLUP pin is connected to VDD and shift

register 1 (Q1 to Q15) is set to 1.

2. PULLUP pin is connected to VSS, and shift

register 1 (Q8 to Q15) is set to 0.

3. When P8 to P15 are not in used, they must

either be set to HIGH or LOW.