M41T256YMT7TR datasheet(9/27 Pages) STMICROELECTRONICS

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M41T256Y

READ Mode

In this mode the master reads the M41T256Y

slave after setting the slave address (see Figure

10., page 9). Following the WRITE Mode Control

Bit (R/W=0) and the Acknowledge Bit, the byte ad-

dresses A(0) and A(1) are written to the on-chip

address pointer (MSB of address byte A(0) is a

“Don’t care”). Next the START condition and slave

address are repeated followed by the READ Mode

Control Bit (R/W=1). At this point the master trans-

mitter becomes the master receiver. The data byte

which was addressed will be transmitted and the

master receiver will send an acknowledge bit to

the slave transmitter. The address pointer is only

incremented on reception of an Acknowledge

Clock. The M41T256Y slave transmitter will now

place the data byte at address An+1 on the bus,

the master receiver reads and acknowledges the

new byte and the address pointer is incremented

to An+2.

This cycle of reading consecutive addresses will

continue until the master receiver sends a STOP

condition to the slave transmitter (see Figure

11., page 10).

Note: Address pointer will wrap around from max-

imum address to minimum address if consecutive

READ or WRITE cycles are performed.

An alternate READ Mode may also be implement-

ed whereby the master reads the M41T256Y slave

without first writing to the (volatile) address point-

er. The first address that is read is the last one

stored in the pointer (see Figure 12., page 10).

Figure 10. Slave Address Location

Note: The most significant bit is sent first.

AI00602

R/W

SLAVE ADDRESS

START

100

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