Samsung S3C6400X User Manual page 985

IIC-BUS INTERFACE
DATA TRANSFER FORMAT
Every byte placed on the SDA line must be eight bits in length. The bytes can be unlimitedly transmitted per
transfer. The first byte following a Start condition will have the address field. The address field can be transmitted
by the master when the IIC-bus is operating in Master mode. Each byte is followed by an acknowledgement
(ACK) bit. The MSB bit of the serial data and addresses are always sent first.
SDA
MSB
1
SCL
S
ACK SIGNAL TRANSMISSION
To complete a one-byte transfer operation, the receiver must send an ACK bit to the transmitter. The ACK pulse
occurs at the ninth clock of the SCL line. Eight clocks are required for the one-byte data transfer. The master will
generate the clock pulse required to transmit the ACK bit.
The transmitter releases the SDA line by making the SDA line High when the ACK clock pulse is received. The
receiver drives the SDA line Low during the ACK clock pulse so that the SDA keeps Low during the High period of
the ninth SCL pulse.
The ACK bit transmit function can be enabled or disabled by software (IICSTAT). However, the ACK pulse on the
ninth clock of SCL is required to complete the one-byte data transfer operation.
Preliminary product information describe products that are in development,
for which full characterization data and associated errata are not yet available.
30-4
Specifications and information herein are subject to change without notice.
Acknowledgement
Signal from Receiver
2 7 8
Byte Complete, Interrupt
within Receiver
Figure 30-3. Data Transfer on the IIC-Bus Block Diagram
9 1 2
ACK
Clock Line Held Low by
receiver and/or transmitter
S3C6400X RISC MICROPROCESSOR
Acknowledgement
Signal from Receiver
9