SH7080_09 Datasheet, PDF (989/1622 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family

Section 18 I²C Bus Interface 2 (I²C2)
18.4.5 Slave Receive Operation
In slave receive mode, the master device outputs the transmit clock and transmit data, and the
slave device returns an acknowledge signal. For slave receive mode operation timing, refer to
figures 18.11 and 18.12. The reception procedure and operations in slave receive mode are
described below.
1. Set the ICE bit in ICCR1 to 1. Set the MLS bit in ICMR and bits CKS3 to CKS0 in ICCR1.
(Initial setting) Set the MST and TRS bits in ICCR1 to select slave receive mode, and wait
until the slave address matches.
2. When the slave address matches in the first frame following detection of the start condition,
the slave device outputs the level specified by ACKBT in ICIER to SDA, at the rise of the 9th
clock pulse. At the same time, RDRF in ICSR is set to read ICDRR (dummy read). (Since the
read data show the slave address and R/W, it is not used.)
3. Read ICDRR every time RDRF is set. If 8th receive clock pulse falls while RDRF is 1, SCL is
fixed low until ICDRR is read. The change of the acknowledge before reading ICDRR, to be
returned to the master device, is reflected to the next transmit frame.
4. The last byte data is read by reading ICDRR.
SCL
(Master output)
9
SDA
(Master output)
SCL
(Slave output)
SDA
(Slave output)
A
RDRF
1
2
3
4
5
6
7
8
9
1
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Bit 7
A
ICDRS
Data 1
Data 2
ICDRR
User
processing
Data 1
[2] Read ICDRR (dummy read)
[2] Read ICDRR
Figure 18.11 Slave Receive Mode Operation Timing (1)
Rev. 4.00 Dec. 15, 2009 Page 929 of 1558
REJ09B0181-0400