7215-072009-7

FIGURE 9. PROGRAMMABLE ACCURATE REAL-TIME DELAY GENERATION

18

11

12

13

14

15

16

17

19

WB0

WB1

WB2

WB3

WB4

WB5

WB6

WB7

1

2

3

4

10M

A

B

TRIG

XTLI

5

XTLO

6

PSCLS

7

RESET

8

9

Vss

OUT

OUTPUT

+V

S1

+V

470k

ƒ

25pF

25pF

TRIGGER IN

+V

1s/1m

2s/2m

4s/4m

8s/8m

16s/16m

32s/32m

64s/64m

128s/128m

NOTE : Crystal Frequency, ƒ = 32,768Hz

Switch: S1 low: Delay increment = 1s; Maximum Delay = 255s

S1 high: Delay increment = 1m; Maximum Delay = 255m

LS7216

s = seconds

m = minutes

MCU

8

WB0-WB7

WB0-WB7

LOAD

LOAD

LS7215/16

LS7215/16

IO

IO

IO

FIGURE 10. LATCHING WEIGHTING BITS FROM A MCU

ODOUT

ODOUT

+3V

+3V

+3V

20

20

3

3

8

8

11-18

11-18

(Example showing separate relay and logic supplies)

+9V

10

+3V

+18V

10

+3V