Cypress STK17T88 manual Pin Configurations, Pin Descriptions

Pin Configurations

Figure 1. 48-Pin SSOP

V CAP	1		48	VCC
NC	2		47	NC
A14	3		46
				HSB
A12	4		45	W
A7	5		44	A13
A6	6		43		A6
A5	7		42		A9
INT	8		41	NC
A4	9		40	A11
NC	10	(TOP)	39	NC
NC	11		38	NC
NC	12		37	NC
VSS	13		36	V SS
NC	14		35	NC
V RTCbat	15		34	V RTCcap
DQ 0	16		33	DQ 6
A3	17		32		G
A2	18		31	A10
A1	19		30		E
A0	20		29	DQ 7
DQ 1	21		28	DQ 5
DQ 2	22		27	DQ 4
X1	23		26	DQ 3
X2	24		25	V CC

STK17T88

Relative PCB Area Usage[1]

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.
		Input	Chip Enable: The active low		input selects the device.
	E			E

WInput 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.

GInput 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.

Note

1. For detailed package size specifications, see Package Diagram on page 21.

Document Number: 001-52040 Rev. *A Page 2 of 22

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