24LC21 MicrochipTechnology, 24LC21 Datasheet - Page 10

• Manufacturer Part Number: 24LC21
• Description: 1K2.5VDualModeI2CSerialEEPROM
• Manufacturer: MicrochipTechnology

24LC21
FIGURE 7-3:
8.0
8.1
This pin is used to transfer addresses and data into and
out of the device, when the device is in the Bi-Direc-
tional Mode. In the Transmit-Only Mode, which only
allows data to be read from the device, data is also
transferred on the SDA pin. This pin is an open drain
terminal, therefore the SDA bus requires a pullup resis-
tor to V
For normal data transfer in the Bi-Directional Mode,
SDA is allowed to change only during SCL low.
Changes during SCL high are reserved for indicating
the START and STOP conditions.
8.2
This pin is the clock input for the Bi-Directional Mode,
and is used to synchronize data transfer to and from the
device. It is also used as the signaling input to switch
the device from the Transmit Only Mode to the Bi-Direc-
tional Mode. It must remain high for the chip to continue
operation in the Transmit Only Mode.
8.3
This pin is the clock input for the Transmit Only Mode.
In the Transmit Only Mode, each bit is clocked out on
the rising edge of this signal. In the Bi-Directional
Mode, a high logic level is required on this pin to enable
write capability.
DS21095F-page 10
BUS ACTIVITY
MASTER
SDA LINE
BUS ACTIVITY
CC
PIN DESCRIPTIONS
SDA
SCL
VCLK
(typical 10K for 100 kHz, 1K for 400 kHz).
SEQUENTIAL READ
CONTROL
BYTE
A
C
K
DATA n
A
C
K
DATA n + 1
A
C
K
DATA n + 2
A
C
K
1996 Microchip Technology Inc.
DATA n + X
N
O
A
C
K
S
T
O
P
P