Turning Ideas Into Reality

ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104

Part Number SIOA7

Copyright © 2014 ABCircuits. Revised September 2014 Page 7 of 10

You can monitor this output with any hexadecimal terminal program like REALTERM. Hyperterm

does not display in hexadecimal.

IA0-6

These are the input bits that will be transmitted on the SOUT- pin. These inputs have internal pull

up resistors.

ADR0-3

These pins determine the device address. A byte received on the SIN- pin with bit 8 set to one is

and bits 7,6, and 5 are zero it is an address byte. The lower 4 bits must mach the ADR0-3 pins,

or the device returns to wait for address mode. If the address matches, the next byte received is

placed on the OA0-6 pins, a positive pulse is generated on the RXP pin. Then the inputs of the

IA0-6 pins are transmitted on the SOUT- pin, with bit 8 of the transmitted byte set to zero. Up to

16 devices can be used on the same communications channel, either on the same board, or on

separate boards if a multi-drop interface such as RS-485 is used.

Device Address

Address Byte (hex)

ADR3

ADR2

ADR1A

ADR0

0

80

Ground

Ground

Ground

Ground

1

81

Ground

Ground

Ground

Open

2

82

Ground

Ground

Open

Ground

3

83

Ground

Ground

Open

Open

4

84

Ground

Open

Ground

Ground

5

85

Ground

Open

Ground

Open

6

86

Ground

Open

Open

Ground

7

87

Ground

Open

Open

Open

8

88

Open

Ground

Ground

Ground

9

89

Open

Ground

Ground

Open

10

8A

Open

Ground

Open

Ground

11

8B

Open

Ground

Open

Open

12

8C

Open

Open

Ground

Ground

13

8D

Open

Open

Ground

Open

14

8E

Open

Open

Open

Ground

15

8F

Open

Open

Open

Open

RXP

This pin outputs a positive pulse after a byte is placed on the OA0-6 pins.

TXE

This pin goes high while the byte on the SOUT- pin is being transmitted. This pin goes low again

after the stop bit has been sent. This pin is designed to drive the RE - (receiver enable) and DE

(driver enable) pins on a RS -485 driver IC. Please note, in RS-485 applications, an external pull

up resistor is required on the SIN- pin.

VSS

Connect to system ground.

VDD

Connect to supply voltage of 2.4 to 5 volts. A .1 uF decoupling capacitor to ground is

recommended.

NOTES:

Make no connection to the NC pins. Pins 9 and 19 must be left unconnected.