Shanghai Belling Corp., Ltd
Pin Descriptions
Pin number
Designation
Type
Name and Functions
BL24C32/64
Address Inputs
DEVICE/PAGE ADDRESSES (A2, A1, A0):
The A2,
A1 and A0 pins are device address inputs that are hardwired or
left not connected for hardware compatibility with other 24Cxx
devices. When the pins are hardwired, as many as eight
1–3
A0 - A2
I
32K/64K devices may be addressed on a single bus system
(device addressing is discussed in detail under the Device
Addressing section). If the pins are left floating, the A2, A1 and
A0 pins will be internally pulled down to GND if the capacitive
coupling to the circuit board VCC plane is <3 pF. If coupling is
>3 pF, recommends connecting the address pins to GND.
5
SDA
I/O
&
Open-dr
ain
Serial Data
SERIAL DATA (SDA):
The SDA pin is bi-directional for
serial data transfer. This pin is open-drain driven and may be
wire-ORed with any number of other open-drain or open-
collector devices.
6
SCL
I
Serial Clock Input
SERIAL CLOCK (SCL):
The SCL input is used to positive
edge clock data into each EEPROM device and negative edge
clock data out of each device.
Write Protect
WRITE PROTECT (WP):
The write protect input, when
connected to GND, allows normal write operations. When WP is
connected high to VCC, all write operations to the memory are
inhibited. If the pin is left floating, the WP pin will be internally
pulled down to GND if the capacitive coupling to the circuit
board VCC plane is <3 pF. If coupling is >3 pF, recommends
connecting the pin to GND. Switching WP to VCC prior to a write
operation creates a software write protect function. The write
protection feature is enabled and operates as shown in the
following
1
.
7
WP
I
4
8
Table 1:
GND
VCC
Write Protect
P
P
Ground
Power Supply
WP Pin Status:
At VCC
At GND
Part of the Array Protected
24C32
Full (32K) Array
24C64
Full (64K) Array
Normal Read/Write Operations
2
BELLING [ SHANGHAI BELLING CO., LTD. ]
