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Bit
Bit Name
4
ICDRE
Initial
Value
R/W
Description
0
R
Transmit Data Write Request Flag
Indicates the ICDR (ICDRT) status in transmit mode.
0: Indicates that the data has been already written to ICDR
(ICDRT) or ICDR is initialized.
1: Indicates that data has been transferred from ICDRT to
ICDRS and is being transmitted, or the start condition
has been detected or transmission has been completed,
thus allowing the next data to be written to.
[Setting conditions]
•
•
[Clearing conditions]
•
•
•
Note that if the ACKE bit is set to 1 in I
enabling acknowledge bit decision, ICDRE is not set when
data is transmitted completely while the acknowledge bit is
1.
When ICDRE is set due to the condition (2) above, ICDRE
is temporarily cleared to 0 when data is written to ICDR
(ICDRT); however, since data is transferred from ICDRT to
ICDRS immediately, ICDRF is set to 1 again. Do not write
data to ICDR when TRS = 0 because the ICDRE flag
value is invalid during the time.
When the start condition is detected from the bus line
2
state in I
C bus format or serial format.
When data is transferred from ICDRT to ICDRS.
1. When data is transmitted completely while ICDRE
= 0 (at the rise of the 9th clock pulse).
2. When data is written to ICDR completely in transmit
mode after data was transmitted while ICDRE = 1.
When data is written to ICDR (ICDRT).
When the stop condition is detected in I
or serial format.
When 0 is written to the ICE bit.
Rev. 1.00 Mar. 12, 2008 Page 613 of 1178
2
Section 18 I
C Bus Interface (IIC)
2
C bus format
2
C bus format thus
REJ09B0403-0100
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