Operation

M41T66

10/33

Figure 6.

Acknowledgement sequence

2.2

READ mode

In this mode the master reads the M41T66 slave after setting the slave address (see

Figure 8 on page 11). 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 M41T66 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-0Fh).

Note:

This is true both in READ mode and WRITE mode.

An alternate READ mode may also be implemented whereby the master reads the M41T66

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 9 on page 11).