M24C64-DRMN3TP datasheet(8/40 Pages) STMICROELECTRONICS

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Signal description

M24C64-A125

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DocID023023 Rev 8

Signal description

2.1

Serial Clock (SCL)

The signal applied on this input is used to strobe the data available on SDA(in) and to output

the data on SDA(out).

2.2

Serial Data (SDA)

SDA is an input/output used to transfer data in or out of the device. SDA(out) 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 between SDA and VCC (Figure 10 indicates how

to calculate the value of the pull-up resistor).

2.3

Chip Enable (E2, E1, E0)

(E2,E1,E0) input signals are used to set the value that is to be looked for on the three least

significant bits (b3, b2, b1) of the 7-bit device select code (see Table 2). These inputs must

be tied to VCC or VSS, as shown in Figure 3. When not connected (left floating), these inputs

are read as low (0).

Figure 3. Device select code

2.4

Write Control (WC)

This input signal is useful for protecting the entire contents of the memory from inadvertent

write operations. Write operations are disabled to the entire memory array when Write

Control (WC) is driven high. Write operations are enabled when Write Control (WC) is either

driven low or left floating.

When Write Control (WC) is driven high, device select and address bytes are

acknowledged, Data bytes are not acknowledged.

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