M14256, M14128

2/12

M14128 in wafer form, please contact your ST

sales office.

extended memory standard. This is a two wire se-

rial interface that uses a bi-directional data bus

and serial clock. The memory device carries a

built-in 7-bit unique Device Type Identifier code

tion. Only one memory device can be attached to

The memory device behaves as a slave device in

chronized by the serial clock. Read and write op-

erations are initiated by a START condition,

generated by the bus master. The START condi-

tion is followed by the Device Select Code which is

composed of a stream of 7 bits (1010000), plus

one read/write bit (R/W) and is terminated by an

acknowledge bit.

When writing data to the memory, the memory de-

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 af-

ter a NoACK for READ.

In order to prevent data corruption and inadvertent

write operations during power up, a Power On Re-

set (POR) circuit is included. The internal reset is

POR threshold value, and all operations are dis-

abled – the device will not respond to any com-

operating voltage, below the POR threshold value,

all operations are disabled and the device will not

must be applied before applying any logic signal.

SIGNAL DESCRIPTION

Serial Clock (SCL)

The SCL input pin is used to synchronize all data

in and out of the memory. A pull up resistor can be

dicates how the value of the pull-up resistor can be

calculated).

Serial Data (SDA)

The SDA pin is bi-directional, and is used to trans-

fer data in or out of the memory. It is an open drain

output that may be wire-OR’ed with other open

drain or open collector signals on the bus. A pull

up resistor must be connected from the SDA bus

pull-up resistor can be calculated).

Figure 2. D22 Contact Connections

AI02204

VCC

GND

SCL

SDA

WC

Note: 1. Except for the rating “Operating Temperature Range”, stresses above those listed in the Table “Absolute Maximum Ratings” may

cause permanent damage to the device. These are stress ratings only, and operation of the device at these or any other conditions

above those indicated in the Operating sections of this specification is not implied. Exposure to Absolute Maximum Rating condi-

tions for extended periods may affect device reliability. Refer also to the ST SURE Program and other relevant quality documents.

2. MIL-STD-883C, 3015.7 (100 pF, 1500

Ω)

3. EIAJ IC-121 (Condition C) (200 pF, 0

Ω)

Symbol

Parameter

Value

Unit

Ambient Operating Temperature

0 to 70

°C

Storage Temperature

-40 to 120

°C

Input or Output range

-0.6 to 6.5

V

Supply Voltage

-0.3 to 6.5

V

4000

V

400

V