Renesas R8C series User Manual

R8C/1A Group, R8C/1B Group 16. Clock Synchronous Serial Interface
Rev.1.30 Dec 08, 2006 Page 223 of 315
REJ09B0252-0130
16.3.4.2 Transmit Operation
In transmit mode, transmit data is output from the SDA pin in synchronization with the falling edge 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 16.42 shows the Operating Timing in Transmit Mode (Clock Synchronous Serial Mode).
The transmit procedure and operation in transmit mode are as follows.
(1) Set the ICE bit in the ICCR1 register to 1 (transfer operation enabled). Set bits CKS0 to CKS3 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 registers ICDRT to ICDRS 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. Continuous
transmission is enabled by writing data to the ICDRT register every time the TDRE bit is set to 1. When
switching from transmit to receive mode, set the TRS bit to 0 while the TDRE bit is set to 1.
Figure 16.42 Operating Timing in Transmit Mode (Clock Synchronous Serial Mode)
SDA
(output)
SCL
87
b7b1
b0
12
ICDRT register
ICDRS register
Processing
by program
1781
b6 b7 b0 b6 b0
TDRE bit in
ICSR register
1
0
TRS bit in
ICCR1 register
1
0
Data 1
Data 2 Data 3
Data 1
Data 2
Data 3
(2) Set TRS bit to 1
(3) Data write to
ICDRT register
(3) Data write to
ICDRT register
(3) Data write to
ICDRT register
(3) Data write to
ICDRT register

Renesas R8C series Specifications

General

Brand	Renesas
Model	R8C series
Category	Computer Hardware
Language	English