Parameter

Symbol

Min. Value

Max.Value

Unit

Remarks

Supply Voltage

3.0

5.5

V

-

Supply Current

-

350

µA

Outputs open

Input Low Voltage

0

0.8

V

-

Input High Voltage

2.0

V

-

Output Low Voltage

-

0.4

V

Output High Voltage

2.5

-

V

Input Current

-

-

15

nA

Leakage

Current

Output Source Current

200

-

µA

Output Sink Current

4

-

mA

Data Bus Off-State

Leakage Current

-

-

15

nA

-

Absolute Maximum Ratings:

Parameter

Symbol

Values

Unit

Voltage at any input

V

Operating Temperature

-40 to +125

oC

Storage Temperature

-65 to +150

oC

Supply Voltage

+7.0

V

7166-082906-5

I/O DESCRIPTION:

(See REGISTER DESCRIPTION for I/O Prgramming.)

Data-Bus (D0 - D7) (Pin 8 - Pin 15). The 8-line data bus is a

three-state I/O bus for interfacing with the system bus.

CS (Chip Select Input) (Pin 2). A logical "0" at this input enables

the chip for Read and Write.

RD (Read Input) (Pin 19). A logical "0" at this input enables the

OSR and the OL to be read on the data bus.

WR (Write Input) (Pin 1). A logical "0" at this input enables the

data bus to be written into the control and data registers.

C/D (Control/Data Input) (Pin 18). A logical "1" at this input en-

ables a control word to be written into one of the four control reg-

isters or the OSR to be read on the I/O bus. A logical "0" enables

a data word to be written into the PR, or the OL to be read on the

I/O bus.

A (Pin 6). Input A is a programmable count input capable of

functioning in three different modes, such as up count input, down

count input and quadrature input. In non-quadrature mode, the

counter advances on the rising edge of Input A.

B (Pin 7). Input B is also a programmable count input that can be

programmed to function either as down count input, or count

direction control gate for input A, or quadrature input. In non- quad-

rature mode, and when programmed as the Down Count input, the

counter advances on the rising edge of Input B. When B is pro-

grammed as the count direction control gate, B = 0 enables A as

the Up Count input and B = 1 enables A as the Down Count input.

When programmed as the direction input, B can switch state only

when A is high.

ABGT/RCTR (Pin 4). This input can be programmed to function

as either inputs A and B enable gate or as external counter reset

input. A logical "0" is the active level on this input. In non-

quadrature mode, if Pin 4 is programmed as A and B enable gate

input, it may switch state only when A is high (if A is clock and B

is direction) or when both A and B are high (if A and B are

clocks). In quadrature mode, if Pin 4 is programmed as A and B

enable gate, it may switch state only when either A or B switches.

LCTR/LLTC (Pin 3 ) This input can be programmed to function

as the external load command input for either the CNTR or the

OL. When programmed as counter load input, the counter is

loaded with the data contained in the PR. When programmed as

the OL load input, the OL is loaded with data contained in the

CNTR. A logical "0" is the active level on this input.

CY (Pin 16) This output can be programmed to serve as one of

the following:

A. CY. Complemented Carry out (active "0").

B. CY. True Carry out (active "1").

C. CYT. Carry Toggle flip-flop out.

D. COMP. Comparator out (active "0")

BW (Pin 17) This output can be programmed to serve as one of

the following:

A. BW. Complemented Borrow out (active "0").

B. BW. True Borrow out (active "1").

C. BWT. Borrow Toggle flip-flop out.

D. COMPT. Comparator Toggle output.