h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 549

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

16.3.5
In slave transmit mode, the slave device outputs the transmit data, while the master device outputs
the receive clock and returns an acknowledge signal. The transmission procedure and operations in
slave transmit mode are described below.
[1] Set the ICE bit in ICCR to 1. Set the MLS bit in ICMR and the MST and TRS bits in ICCR
[2] When the slave address matches in the first frame following detection of the start condition,
[3] After clearing the IRIC flag to 0, write data to ICDR. The TDRE internal flag is cleared to 0.
[4] When one frame of data has been transmitted, the IRIC flag in ICCR is set to 1 at the rise of
[5] To continue transmission, clear the IRIC flag to 0, then write the next data to be transmitted
according to the operating mode.
the slave device drives SDA low at the 9th clock pulse and returns an acknowledge signal. At
the same time, the IRIC flag in ICCR is set to 1. If the IEIC bit in ICCR has been set to 1, an
interrupt request is sent to the CPU. .If the 8th data bit (R/W) is 1, the TRS bit in ICCR is set
to 1, and the mode changes to slave transmit mode automatically. The TDRE internal flag is
set to 1. The slave device drives SCL low from the fall of the transmit clock until ICDR data is
written.
The written data is transferred to ICDRS, and the TDRE internal flag and the IRIC and IRTR
flags are set to 1 again. After clearing the IRIC flag to 0, write the next data to ICDR. The
slave device sequentially sends the data written into ICDR in accordance with the clock output
by the master device at the timing shown in figure 16.11.
the 9th transmit clock pulse. If the TDRE internal flag has been set to 1, this slave device
drives SCL low from the fall of the transmit clock until data is written to ICDR. The master
device drives SDA low at the 9th clock pulse, and returns an acknowledge signal. As this
acknowledge signal is stored in the ACKB bit in ICSR, this bit can be used to determine
whether the transfer operation was performed normally. When the TDRE internal flag is 0, the
data written into ICDR is transferred to ICDRS, transmission is started, and the TDRE internal
flag and the IRIC and IRTR flags are set to 1 again.
into ICDR. The TDRE internal flag is cleared to 0.
Transmit operations can be performed continuously by repeating steps [4] and [5]. To end
transmission, write H'FF to ICDR to release SDA on the slave side. When SDA is changed
from low to high when SCL is high, and the stop condition is detected, the BBSY flag in ICCR
is cleared to 0.
Slave Transmit Operation
Section 16 I
Rev. 4.00 Jun 06, 2006 page 495 of 1004
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C Bus Interface [H8S/2138 Group Option]
REJ09B0301-0400