p2125vps20 Renesas Electronics Corporation., p2125vps20 Datasheet - Page 407

• Manufacturer Part Number: p2125vps20
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

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Section 16 I
C Bus Interface (IIC)
(TRS = 0), no data is transferred from ICDRT to ICDRS. Note that data should not be written to
ICDR in receive mode.
Reading receive data from ICDR is performed after data is transferred from ICDRS to ICDRR.
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If I
C is in receive mode and no previous data remains in ICDRR (the ICDRF flag is 0), data is
transferred automatically from ICDRS to ICDRR, following reception of one frame of data using
ICDRS. If additional data is received while the ICDRF flag is 1, data is transferred automatically
from ICDRS to ICDRR by reading from ICDR. In transmit mode, no data is transferred from
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ICDRS to ICDRR. Always set I
C to receive mode before reading from ICDR.
If the number of bits in a frame, excluding the acknowledge bit, is less than eight, transmit data
and receive data are stored differently. Transmit data should be written justified toward the MSB
side when MLS = 0 in ICMR, and toward the LSB side when MLS = 1. Receive data bits should
be read from the LSB side when MLS = 0, and from the MSB side when MLS = 1.
ICDR can be written to and read from only when the ICE bit is set to 1 in ICCR. The initial value
of ICDR is undefined.
16.3.2
Slave Address Register (SAR)
SAR sets the slave address and selects the communication format. If the LSI is in slave mode with
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the I
C bus format selected, when the FS bit is set to 0 and the upper 7 bits of SAR match the
upper 7 bits of the first frame received after a start condition, the LSI operates as the slave device
specified by the master device. SAR can be accessed only when the ICE bit in ICCR is cleared to
0.
Rev. 1.00 Sep. 21, 2006 Page 369 of 658
REJ09B0310-0100