STK17T88
Document Number: 001-52040 Rev. *A
Page 2 of 22
Pin Configurations
Figure 1. 48-Pin SSOP
VSS
A14
A12
A7
A6
DQ 0
DQ 1
VCC
DQ 2
A3
A2
A1
VCAP
A13
A6
A9
A11
A10
DQ 7
DQ 6
VSS
A0
NC
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
NC
E
X1
X2
23
24
A5
INT
NC
NC
NC
NC
A4
48
47
46
45
VCC
HSB
NC
NC
W
NC
DQ 5
DQ 3
DQ 4
G
C
N
C
N
VRTCbat
VRTCcap
(TOP)
Note
1. For detailed package size specifications, see Package Diagram on page 21.
Pin Descriptions
Pin Name
IO Type
Description
A14-A0
Input
Address: The 15 address inputs select one of 32,768 bytes in the nvSRAM array or one of 16 bytes
in the clock register map.
DQ7-DQ0
I/O
Data: Bi-directional 8-bit data bus for accessing the nvSRAM 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
selected on 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 caused the DQ pins to tri-state.
X1
Output
Crystal Connection, drives crystal on startup.
X2
Input
Crystal Connection for 32.768 kHz crystal.
VRTCcap
Power Supply
Capacitor supplied backup RTC supply voltage (Left unconnected if VRTCbat is used).
VRTCbat
Power Supply
Battery supplied backup RTC supply voltage (Left unconnected if VRTCcap is used).
VCC
Power Supply
Power: 3.0V, +20%, -10%
HSB
I/O
Hardware Store Busy: When low this output indicates a Store is in progress. When pulled low
external to the chip, it initiates a nonvolatile STORE operation. A weak pull up resistor keeps this
pin high if not connected. (Connection Optional).
INT
Output
Interrupt Control: 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)
VCAP
Power Supply
Autostore™ Capacitor: Supplies power to nvSRAM during power loss to store data from SRAM
to nonvolatile storage elements.
VSS
Power Supply
Ground
NC
No Connect
Unlabeled pins have no internal connections.
Relative PCB Area Usage[1]
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