Tel: 886-2-66296288

Fax: 886-2-29174598

URL: http://www.princeton.com.tw

PT8146 V1.1

- 7 -

February, 2006

8-Bit 12-Ch I/O DAC

PT8146

I/O EXPANDER (CHANNEL SELECT = “1101”): SERIAL → PARALLEL

CONVERSION

Performs parallel conversion of data bits D4 to DF for output on pins D0 to D11.

Note that only those pins designated for output in the ESR (expander status register) are output.

Shift register

DF

DE

DD

DC

DB

DA

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

Parallel I/O pins (output state)

D

11

D

10

D

9

D

8

D

7

D

6

D

5

D

4

D

3

D

2

D

1

D

0

I/O EXPANDER (CHANNEL SELECT = “1110”): PARALLEL → SERIAL

CONVERSION

Writes data from D0 to D11 pins to bits D4 to DF in the shift register.

Data is output to the SO pin on the shift clock (CLK) signal. (The first 4 bits output data D0 to D3, so the

converted output should be read as data bits 5 through 16.)

Note that the data value is “0” for pins designated for output in the ESR (expander status register) as

well as analog output pins.

Shift register

DF

DE

DD

DC

DB

DA

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

Parallel I/O pins (output state)

D

11

D

10

D

9

D

8

D

7

D

6

D

5

D

4

D

3

D

2

D

1

D

0