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Section 17 I
2
C Bus Interface 3
R01UH0134EJ0400 Rev. 4.00 Page 873 of 2108
Sep 24, 2014
SH7262 Group, SH7264 Group
17.4.4 Slave Transmit Operation
In slave transmit mode, the slave device outputs the transmit data, while the master device outputs
the receive clock and returns an acknowledge signal. For slave transmit mode operation timing,
refer to figures 17.9 and 17.10.
The transmission procedure and operations in slave transmit mode are described below.
1. Set the ICE bit in ICCR1 to 1. Set bits CKS[3:0] 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 this time, if the 8th bit data (R/W) is 1, the TRS bit in ICCR1 and the TDRE bit
in ICSR are set to 1, and the mode changes to slave transmit mode automatically. The
continuous transmission is performed by writing transmit data to ICDRT every time TDRE is
set.
3. If TDRE is set after writing last transmit data to ICDRT, wait until TEND in ICSR is set to 1,
with TDRE = 1. When TEND is set, clear TEND.
4. Clear TRS for the end processing, and read ICDRR (dummy read). SCL is opened.
5. Clear TDRE.