24-BIT QUADRATURE COUNTER

FEATURES:

• Programmable modes are: Up/Down,

Binary, BCD, 24 Hour Clock, Divide-by-N,

x1 or x2 or x4 Quadrature and Single-Cycle.

• DC to 25MHz Count Frequency.

• 8-Bit I/O Bus for uP Communication and Control.

• 24-Bit comparator for pre-set count comparison.

• Readable status register.

• Input/Output TTL and CMOS compatible.

• LS7166 (DIP); LS7166-S (SOIC);

LS7166-TS24 (24-Pin TSSOP)

- See Figure 1 -

GENERAL DESCRIPTION:

The LS7166 is a CMOS, 24-bit counter that can be pro-

grammed to operate in several different modes. The oper-

ating mode is set up by writing control words into internal

control registers (see Figure 8). There are three 6-bit and

one 2-bit control registers for setting up the circuit functional

characteristics. In addition to the control registers, there is a

5-bit output status register (OSR) that indicates the current

counter status. The IC communicates with external circuits

through an 8-bit three state I/O bus. Control and data words

are written into the LS7166 through the bus. In addition to

the I/O bus, there are a number of discrete inputs and out-

puts to facilitate instantaneous hardware based control func-

tions and instantaneous status indication.

REGISTER DESCRIPTION:

Internal hardware registers are accessible through the I/O

bus (D0 - D7) for READ or WRITE when CS = 0. The C/D in-

put selects between the control registers (C/D = 1) and the

data registers (C/D = 0) during a READ or WRITE operation.

(See Table 1)

The information included herein is believed to be

accurate and reliable. However, LSI Computer Systems,

Inc. assumes no responsibilities for inaccuracies, nor for

any infringements of patent rights of others which may

result from its use.

December 2008

FIGURE 1

LSI/CSI

LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747 (631) 271-0400 FAX (631) 271-0405

LS7166

PIN ASSIGNMENTS - Top View

7166-121508-1

20-PIN

DIP and SOIC

LCTR/LLTC

ABGT/RCTR

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

D1

D2

D3

D4

D5

D6

D7

CY

BW

C/D

RD

WR

CS

A

B

D0

24-PIN

TSSOP

1

2

3

4

5

6

7

8

9

15

16

17

18

19

20

21

22

23

24

12

CS

WR

NC

NC

NC

A

LCTR/LLTC

ABGT/RCTR

B

D0

D1

D2

D3

D4

D5

D6

D7

NC

C/D

RD

BW

CY

11

10

13

14

UL

®

A3800