24LCS22A-I/P Microchip Technology, 24LCS22A-I/P Datasheet - Page 5

• Manufacturer Part Number: 24LCS22A-I/P
• Description: IC EEPROM 2KBIT 400KHZ 8DIP
• Manufacturer: Microchip Technology

Specifications of 24LCS22A-I/P

• Format - Memory: EEPROMs - Serial
• Memory Type: EEPROM
• Memory Size: 2K (256 x 8)
• Speed: 100kHz, 400kHz
• Interface: I²C, 2-Wire Serial
• Voltage - Supply: 2.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 24LCS22AI/P

3.0
Before the 24LCS22A can be switched into the
Bidirectional mode (Figure 3-1), it must enter the
Transition mode, which is done by applying a valid
high-to-low transition on the Bidirectional mode clock
(SCL). As soon as it enters the Transition mode, it looks
for a control byte ‘1010 000X’ on the I
starts to count pulses on VCLK. Any high-to-low
transition on the SCL line will reset the count. If it sees
a pulse count of 128 on VCLK while the SCL line is idle,
it will revert back to the Transmit-Only mode, and
transmit its contents starting with the Most Significant
bit in address 00h. However, if it detects the control
byte on the I
Bidirectional mode. Once the device has made the
transition to the Bidirectional mode, the only way to
switch the device back to the Transmit-Only mode is to
remove power from the device. The mode transition
process is shown in detail in Figure 3-3.
FIGURE 3-1:
FIGURE 3-2:
© 2009 Microchip Technology Inc.
MODE
SCL
SDA
VCLK
VCLK count =
MODE
VCLK
BIDIRECTIONAL MODE
SDA
SCL
Transmit-Only
VCLK count =
2
C bus (Figure 3-2), it will switch to the
Transmit-Only
MODE TRANSITION WITH RECOVERY TO TRANSMIT-ONLY MODE
SUCCESSFUL MODE TRANSITION TO BIDIRECTIONAL MODE
1
T
1
2
VHZ
Transition mode with possibility to return to Transmit-Only mode
Bidirectional
2
n < 128
2
C™ bus, and
n
3
S
0
4
1
0
127 128
1
Once the device has switched into the Bidirectional
mode, the VCLK input is disregarded, with the
exception that a logic high level is required to enable
write capability. In Bidirectional mode the user has
access to the entire 2K array, whereas in the Transmit-
Only mode, the user can only access the first 1K. This
mode
transmission protocol (I
that sends data on the bus is defined to be the
transmitter, and a device that receives data from the
bus is defined to be the receiver. The bus must be
controlled by a master device that generates the
Bidirectional mode clock (SCL), controls access to the
bus and generates the Start and Stop conditions, while
the 24LCS22A acts as the slave. Both master and
slave can operate as transmitter or receiver, but the
master device determines which mode is activated. In
the Bidirectional mode, the 24LCS22A only responds
to commands for device ‘1010 000X’.
0
(MSB of data in 00h)
Bit8
Recovery to Transmit-Only mode
supports
0
0
a
0
two-wire
2
C). In this protocol, a device
24LCS22A
0
ACK
bidirectional
DS21682E-page 5
Bidirectional
permanently
data