Philips Semiconductors
LCD controllers/drivers
Product specification
PCF2113x
A master receiver must signal an end of data to the
transmitter by not generating an acknowledge bit on the
last byte that has been clocked out of the slave. In this
event the transmitter must leave the data line HIGH to
enable the master to generate a STOP condition.
10.2.1 I2C-BUS PROTOCOL
Before any data is transmitted on the I2C-bus, the device
which should respond is addressed first. The addressing is
always carried out with the first byte transmitted after the
START procedure. The I2C-bus configuration for the
different PCF2113x read and write cycles is shown in
Figs 24 to 26. The slow down feature of the I2C-bus
protocol (receiver holds SCL LOW during internal
operations) is not used in the PCF2113x.
10.2.2 DEFINITIONS
• Transmitter: the device which sends the data to the bus
• Receiver: the device which receives the data from the
bus
• Master: the device which initiates a transfer generates
clock signals and terminates a transfer
• Slave: the device addressed by a master
• Multi-master: more than one master can attempt to
control the bus at the same time without corrupting the
message
• Arbitration: procedure to ensure that if more than one
master simultaneously tries to control the bus, only one
is allowed to do so and the message is not corrupted
• Synchronization: procedure to synchronize the clock
signals of two or more devices.
MASTER
TRANSMITTER/
RECEIVER
SDA
SCL
SLAVE
RECEIVER
SLAVE
TRANSMITTER/
RECEIVER
MASTER
TRANSMITTER
MASTER
TRANSMITTER/
RECEIVER
MGA807
Fig.20 System configuration.
handbook, full pagewidth
SDA
SCL
2001 Dec 19
data line
stable;
data valid
change
of data
allowed
Fig.21 Bit transfer.
34
MBC621