R8C16 Datasheet, PDF (176/279 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / R8C/Tiny SERIES

R8C/16 Group, R8C/17 Group
15. I²C bus interface (IIC)
15.4.1 Transmit Operation
In transmit mode, transmit data is output from the SDA pin synchronizing with the fall of the transfer
clock. The transfer clock is output when the MST bit in the ICCR1 register is set to “1” and input when
the MST bit is set to “0”. Figure 15.19 shows the Operating Timing in Transmit Mode (Clock
Synchronous Serial Mode).
The transmit procedure and operation in transmit mode are shown below.
(1) Set the ICE bit in the ICCR1 register to “1” (transfer operation enabled). Set the CKS0 to
CKS3 bits in the ICCR1 register and set the MST bit (initial setting).
(2) The TDRE bit in the ICSR register is set to “1” by selecting transmit mode after setting the TRS
bit in the ICCR1 register to “1”.
(3) Data is transferred from the ICDRT to ICDRS registers and the TDRE bit is automatically set
to “1” by writing transmit data to the ICDRT register after confirming that the TDRE bit is set to
“1”. When writing data to the ICDRT register every time the TDRE bit is set to “1”, the
continuous transmit is enabled. When switching from transmit to receive modes, set the TRS
bit to “0” while the TDRE bit is set to “1”.
SCL
SDA
(Output)
TRS Bit in ^{“1”}
ICCR1 Register
“0”
TDRE Bit in ^{“1”}
ICSR Register
“0”
ICDRT Register
1
2
7
8
1
7
8
1
b0
b1
b6
b7
b0
b6
b7
b0
Data 1
Data 2
Data 3
ICDRS Register
Data 1
Data 2
Data 3
Process
by program
(3) Data write to
ICDRT register
(2) Set TRS bit to “1”
(3) Data write to
ICDRT register
(3) Data write to
ICDRT register
(3) Data write to
ICDRT register
Figure 15.19 Operating Timing in Transmit Mode (Clock Synchronous Serial Mode)
Rev.2.10 Jan 19, 2006 Page 163 of 254
REJ09B0169-0210