IBM T860 9494-HWN, Service Manual

Page: 33 / 44

- 33 -
S524C20D11/20D21/80D41/80D81 SERIAL EEPROM
Start/Stop
Logic
Slave Adress
Comparator
Word Address
Pointer
HV Generation
Timing Control
Column Decoder
Row
decoder
Data Register
Dout and ACk
Control Logic
EEPROM
Cell Array
128 x 8 bits
256 x 8 bits
512 x 8 bits
1024 x 8 bits
SDA
SCL
WP
A0
A1
A2
BLOCK DIAGRAM
S524C20D11/20D21/
80D41/80D81
Vcc
A0 A1 A2 Vss
Wp SCL SDA
PIN CONFIGURATION
PIN FUNCTION
NOTE: See following page for diagrams of pin circuit types 1,2 and 3.
Name
A0, A1, A2
Vss
Input
-
1
3
2
1
-
-
Input pins for device address selection. To configure a device adress,
these pins should be connected to the Vcc of Vss of the device.
SDA
I/O
SCL Input
Bi-directionl data pin for the I
2
C-bus serial data interface. Schmitt
trigger input and open-drain output. An external pull-up resistor must
be connected to Vcc. Typical values for this pull-up resistor are 4.7k
Ω
(100kHz)and 1k
Ω
(400kHz)
.
SDA
I/O
Input pin for hardware write protection control. If you tie this pin to Vcc,
the write function is disabled to protect previously written data in the
entire memory; if you tie it to Vss, the write function is enabled.
Ground pin.
Schmitt trigger input pin for serial clock input.
Vcc
- Single power supply.
Type
Circuit
Type
Description