HD64F2168 Datasheet, PDF (501/874 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer

Initial
Bit
Bit Name Value R/W Description
4
ICDRE 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 complete,
thus allowing the next data to be written to.
[Setting conditions]
• When the start condition is detected from the bus line
state in I²C 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.
[Clearing conditions]
• When data is written to ICDR (ICDRT).
• When the stop condition is detected in I²C bus format
or serial format.
• When 0 is written to the ICE bit.
Note that if the ACKE bit is set to 1 in I²C bus format thus
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.
Rev. 3.00, 03/04, page 461 of 830