
16. Inter Integrated Circuit (I2C)
MC97F6108A User’s manual
170
16.4
Data transfer
Every byte put on the SDA line must be 8-bits long. The number of bytes that can be transmitted per
transfer is unlimited. Each byte has to be followed by an acknowledge bit. Data is transferred with the
most significant bit (MSB) first. If a slave can’t r
eceive or transmit another complete byte of data until it
has performed some other function, it can hold the clock line SCL LOW to force the master into a wait
state. Data transfer then continues when the slave is ready for another byte of data and releases clock
line SCL.
Figure 78. Data Transfer on the I2C-Bus
START or Repeated
START Condition
S or
Sr
STOP or Repeated
START Condition
Sr or
P
MSB
Acknowledgement Signal
form Slave
Acknowledgement Signal
form Slave
Byte Complete,
Interrupt within Device
Clock line held low while
interrupts are served.
1
9
1
9
ACK
ACK
SDA
SCL
Sr
P