
MOTOROLA
Revision 8.0 - 28 November 2001 : MCM20027
28
MOTOROLA
SEMICONDUCTOR TECHNICAL DATA
ImageMOS
10.9 Register Write
Writing the MCM20027 registers is accomplished with
the following I2C transactions (see
Figure 17
):
Master transmits a START
Master transmits the MCM20027 Slave Calling Ad-
dress with “WRITE” indicated (BYTE=66
h
, 102
d
,
01100110
b
)
MCM20027 slave sends acknowledgment by forc-
ing the SDATA Low during the 9th clock, if the Call-
ing Address was received
Master transmits the MCM20027 Register Address
MCM20027 slave sends acknowledgment by forc-
ing the SDATA Low during the 9th clock after re-
ceiving the Register Address
Master transmits the data to be written into the reg-
ister at the previously received Register Address
MCM20027 slave sends acknowledgment by forc-
ing the SDATA Low during the 9th clock after re-
ceiving the data to be written into the Register
Address
Master transmits STOP to end the write cycle
10.10 Register Read
Reading the MCM20027 registers is accomplished with
the following I2C transactions (see
Figure 18
):
Master transmits a START
Master transmits the MCM20027 Slave Calling Ad-
dress with “WRITE” indicated (BYTE=66
h
, 102
d
,
01100110
b
)
MCM20027 slave sends acknowledgment by forc-
ing the SData Low during the 9th clock, if the Calling
Address was received
Master transmits the MCM20027 Register Address
MCM20027 slave sends acknowledgment by forc-
ing the SData Low during the 9th clock after receiv-
ing the Register Address
Master transmits a Repeated START
Master transmits the MCM20027 Slave Calling Ad-
dress with “READ” indicated (BYTE = 67
h,
103
d
,
01100111
b
)
MCM20027 slave sends acknowledgment by forc-
ing the SDATA Low during the 9th clock, if the Call-
ing Address was received
At this point, the MCM20027 transitions from a
“Slave-Receiver” to a “Slave-Transmitter”
MCM20027 sends the SCLK and the Register Data
contained in the Register Address that was previ-
ously received from the master; MCM20027 transi-
tions to slave-receiver
Master does not send an acknowledgment (NAK)
Master transmits STOP to end the read cycle