M34F04 Datasheet, PDF (4/20 Pages) STMicroelectronics – 4Kbit Serial I2C Bus EEPROM With Hardware Write Control on Top Half of Memory

M34F04
SUMMARY DESCRIPTION
The M34F04 is an electrically erasable
programmable memory (EEPROM), organized as
512 x 8.
Figure 2. Logic Diagram
VCC
2
E1-E2
SCL
WC
M34F04
SDA
VSS
AI09072
These devices are compatible with the I²C memo-
ry protocol. This is a two wire serial interface that
uses a bi-directional data bus and serial clock. The
devices carry a built-in 4-bit Device Type Identifier
code (1010) in accordance with the I²C bus defini-
tion.
The device behaves as a slave in the I²C protocol,
with all memory operations synchronized by the
serial clock. Read and Write operations are initiat-
ed by a Start condition, generated by the bus mas-
ter. The Start condition is followed by a Device
Select Code and RW bit (as described in Table 2),
terminated by an acknowledge bit.
When writing data to the memory, the device in-
serts an acknowledge bit during the 9^th bit time,
following the bus master’s 8-bit transmission.
When data is read by the bus master, the bus
master acknowledges the receipt of the data byte
in the same way. Data transfers are terminated by
a Stop condition after an Ack for Write, and after a
NoAck for Read.
Table 1. Signal Names
E1, E2
Chip Enable
SDA
Serial Data
SCL
Serial Clock
WC
Write Control
V_CC
V_SS
Supply Voltage
Ground
Power On Reset: V_CC Lock-Out Write Protect
In order to prevent data corruption and inadvertent
Write operations during Power-up, a Power On
Reset (POR) circuit is included. The internal reset
is held active until V_CC has reached the POR
threshold value, and all operations are disabled –
the device will not respond to any command. In the
same way, when V_CC drops from the operating
voltage, below the POR threshold value, all oper-
ations are disabled and the device will not respond
to any command. A stable and valid V_CC must be
applied before applying any logic signal.
Figure 3. SO Connections
M34F04
NC 1
E1 2
E2 3
VSS 4
8 VCC
7 WC
6 SCL
5 SDA
AI09073
Note: 1. NC = Not Connected
2. See page 17 (onwards) for package dimensions, and how
to identify pin-1.
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