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CY14B256K
Document Number: 001-06431 Rev. *H Page 2 of 28
Pin Configurations
Figure 1. 48-Pin SSOP
Pin Definitions
Pin Name Alt IO Type Description
A
0
–A
14
Input Address Inputs. Used to select one of the 32,768 bytes of the nvSRAM.
DQ0-DQ7 Input or Output Bidirectional Data IO lines. Used as input or output lines depending on operation.
NC No Connect No Connects. This pin is not connected to the die.
WE
W
Input Write Enable Input, Active LOW. When the chip is enabled and WE is LOW, data on the IO
pins is written to the specific address location.
CE
E
Input Chip Enable Input, Active LOW. When LOW, selects the chip. When HIGH, deselects the chip.
OE
G
Input Output Enable, Active LOW. The active LOW OE input enables the data output buffers during
read cycles. Deasserting OE
high causes the IO pins to tri-state.
X
1
Output Crystal Connection. Drives crystal on start up.
X
2
Input Crystal Connection for 32.768 kHz Crystal.
V
RTCcap
Power Supply Capacitor Supplied Backup RTC Supply Voltage. (Left unconnected if V
RTCbat
is used)
V
RTCbat
Power Supply Battery Supplied Backup RTC Supply Voltage. (Left unconnected if V
RTCcap
is used)
INT Output Interrupt Output. It is programmed to respond to the clock alarm, the watchdog timer, and the
power monitor. Programmable to either active HIGH (push or pull) or LOW (open drain).
V
SS
Ground Ground for the Device. It is connected to ground of the system.
V
CC
Power Supply Power Supply Inputs to the Device.
HSB
Input or Output Hardware Store Busy (HSB). When low, this output indicates a Hardware Store is in progress.
When pulled low external to the chip, it initiates a nonvolatile STORE operation. A weak internal
pull up resistor keeps this pin HIGH if not connected (connection optional).
V
CAP
Power Supply AutoStore Capacitor. Supplies power to nvSRAM during power loss to store data from SRAM
to nonvolatile elements.
V
CAP
A
14
A
12
A
7
A
6
A
5
A
4
V
CC
HSB
WE
A
13
A
8
A
9
A
11
OE
A
10
DQ
DQ7
6
DQ5
CE
DQ4
DQ3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
INT
NC
NC
NC
V
SS
NC
DQ0
A
3
A
2
A
1
A
0
DQ1
DQ2
NC
NC
NC
NC
V
SS
NC
V
CC
48-SSOP
Top View
(Not To Scale)
NC
V
RTCbat
X
1
X
2
V
RTCcap
NC
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