Renesas H8S/2158 User Manual page 453

Bit Functions in Normal Serial Communication Interface Mode (When SMIF in SCMR = 0)
Bit Bit Name
7 TDRE
6 RDRF
Section 16 Serial Communication Interface (SCI, IrDA, and CRC)
Initial Value R/W
R/(W) *
1
R/(W) *
0
Description
Transmit Data Register Empty
Indicates whether TDR contains transmit data.
[Setting conditions]
•
When the TE bit in SCR is 0
•
When data is transferred from TDR to TSR
and TDR is ready for data write
[Clearing conditions]
•
When 0 is written to TDRE after reading TDRE
= 1
•
When a TXI interrupt request is issued
allowing DTC to write data to TDR
•
When RFU is activated by TDRE = 1 allowing
data to be written to TDR (only for SCI_0 and
SCI_2)
Receive Data Register Full
Indicates that receive data is stored in RDR.
[Setting condition]
•
When serial reception ends normally and
receive data is transferred from RSR to RDR
[Clearing conditions]
•
When 0 is written to RDRF after reading
RDRF = 1
•
When an RXI interrupt request is issued
allowing DTC to read data from RDR
•
When RFU is activated by RDRE = 1 allowing
data to be read from RDR (only for SCI_0 and
SCI_2)
The RDRF flag is not affected and retains its
previous value when the RE bit in SCR is cleared
to 0.
Rev. 3.00 Jan 25, 2006 page 399 of 872
REJ09B0286-0300