24aa174 Microchip Technology Inc., 24aa174 Datasheet - Page 8

• Manufacturer Part Number: 24aa174
• Description: 16k 1.8v Cascadable I 2c? Serial Eeprom With Otp Security Page
• Manufacturer: Microchip Technology Inc.

24AA174
8.0
8.1
This is a Bi-directional pin used to transfer addresses and
data into and data out of the device. It is an open drain ter-
minal, therefore the SDA bus requires a pullup resistor to
V
For normal data transfer 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 input is used to synchronize the data transfer from
and to the device.
8.3
This pin must be connected to either V
If tied to V
(read/write the entire memory 000-7FF).
If tied to V
entire memory will be write-protected. Read opera-
tions are not affected.
This feature allows the user to use the 24AA174 as a
serial ROM when WP is enabled (tied to V
8.4
These pins are used to configure the proper chip
address in multiple-chip applications (more than one
24AA174 on the same bus). The levels on these pins
are compared to the corresponding bits in the slave
address. The chip is selected if the compare is true.
FIGURE 8-1:
FIGURE 8-2:
DS21102G-page 8
CC
(typical 10K for 100 kHz, 1K for 400 kHz).
PIN DESCRIPTIONS
SDA Serial Address/Data Input/Output
SCL Serial Clock
WP
A0, A1, A2
BUS ACTIVITY
MASTER
SDA LINE
BUS ACTIVITY
CC
SS
, WRITE operations are inhibited. The
, normal memory operation is enabled
CURRENT ADDRESS READ
RANDOM READ
S
1 A2 A1A0B2B1B0
S
T
A
R
T
BUS ACTIVITY
MASTER
SDA LINE
BUS ACTIVITY
CONTROL
BYTE
SS
A
C
K
or V
CC
).
CC
ADDRESS (n)
S 1 A2 A1 A0 B2 B1 B0
R
S
T
A
T
.
WORD
CONTROL
BYTE
A
C
K
S
T
A
R
T
Up to eight 24AA174s may be connected to the same
bus. These pins must be connected to either V
8.5
The security row is enabled by sending the control
sequence with the I
the control byte must be set to a one for a READ
OPERATION or a zero for the OTP WRITE OPERA-
TION. The SECURITY ACCESS DATA is always read
starting at byte 0 for N bytes up to and including byte
15. (See Figure 4-2).
8.6
The S.A.W. data is written to the device using a normal
page write following the proper control access
sequence. Upon receiving the final stop bit, the internal
write sequence will commence. At the completion of
the internal write sequence a fuse will be set disabling
the write function for the 16 byte security page.
8.7
The security access read is accomplished by executing
the normal read sequences, following the security
access control sequence with bit 0 set to a one. The
security page read starts at data byte 0.
S
Note:
A
C
K
CONTROL
BYTE
Security Access Control
Security Access Write
Security Access Read
DATA n
The level on A1 is compared to the inverse
of the slave address.
2
A
C
K
C slave address of 0110. Bit 0 of
O
N
A
C
K
2004 Microchip Technology Inc.
O
S
T
P
P
DATA (n)
N
O
C
A
K
S
T
O
P
P
SS
or V
CC
.