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
A0–A14
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.
X1
Output
Crystal Connection. Drives crystal on start up.
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)
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).
VSS
Ground
Ground for the Device. It is connected to ground of the system.
VCC
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).
VCAP
Power Supply
AutoStore Capacitor. Supplies power to nvSRAM during power loss to store data from SRAM
to nonvolatile elements.
VCAP
A14
A12
A7
A6
A5
A4
VCC
HSB
WE
A13
A8
A9
A11
OE
A10
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
VSS
NC
DQ0
A3
A2
A1
A0
DQ1
DQ2
NC
NC
NC
NC
VSS
NC
VCC
48-SSOP
Top View
(Not To Scale)
NC
VRTCbat
X1
X2
VRTCcap
NC
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