STK17T88

April 2005

Document Control #ML0024 rev 1.2

2

PACKAGES

PIN DESCRIPTIONS

Pin Name

I/O

Description

Input

Address: The 15 address inputs select one of 32,752 bytes in the nvSRAM array or one of 16 bytes in the clock

register map.

I/O

Data: Bi-directional 8-bit data bus for accessing the nvSRAM array and RTC.

E

Input

Chip Enable: The active low E

input selects the device.

W

Input

Write Enable: The active low W enables data on the DQ pins to be written to the address location latched by the

falling edge of E .

G

Input

Output Enable: The active low G input enables the data output buffers during read cycles. De-asserting G high

causes the DQ pins to tri-state.

Output

Crystal Connection, drives crystal on startup.

Input

Crystal Connection for 32.768 kHz crystal.

Power Supply

Power Supply

Power Supply

Power 3.0V +20%, -10%

HSB

I/O

Hardware Store Busy: When low this output indicates a Hardware Store is in progress. When pulled low external

to the chip it will initiate a nonvolatile STORE operation. A weak internal pull up resistor keeps this pin high if not

connected. (Connection Optional)

INT

Output

Interrupt Output: Can be programmed to respond to the clock alarm, the watchdog timer and the power monitor.

Programmable to either active high (push/pull) or active low (open-drain).

Power Supply

Autostore

Capacitor: Supplies power to nvSRAM during power loss to store data from SRAM to nonvolatile

elements.

Power Supply

Ground

(Blank)

No Connect

Unlabeled pins have no internal connection.

48 Pin SSOP

40 Pin PDIP

INT

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

W

HSB

G

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

E

G

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

21

22

23

24

25

26

27

28

29

30

31

32

W

HSB

E

17

18

19

20

33

34

35

36

37

38

39

40

INT

48 Pin SSOP

Relative PCB area usage.

See website for detailed

package size specifications.