M4182RM6E datasheet(17/58 Pages) STMICROELECTRONICS

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M41T82 M41T83

Operation

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2.2

Read mode

In this mode the master reads the M41T8x slave after setting the slave address (see

Figure 13 on page 18). Following the WRITE Mode control bit (R/W = 0) and the

Acknowledge bit, the word address 'An' is written to the on-chip address pointer. Next the

START condition and slave address are repeated followed by the READ Mode control bit

(R/W = 1). At this point the master transmitter 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 M41T8x 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. The system-to-user transfer of clock data will be

halted whenever the address being read is a clock address (00h to 07h). The update will

resume due to a Stop Condition or when the pointer increments to any non-clock address

(08h-1Fh).

Note:

This is true both in READ Mode and WRITE Mode.

An alternate READ Mode may also be implemented whereby the master reads the M41T8x

slave without first writing to the (volatile) address pointer. The first address that is read is the

last one stored in the pointer (see Figure 14 on page 18).

Figure 12.

Slave address location

AI00602

R/W

SLAVE ADDRESS

START

100

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