Datasheet

Section 15 Serial Communication Interface (SCI, IrDA)
Rev. 4.00 Sep 27, 2006 page 437 of 1130
REJ09B0327-0400
SSR is initialized to H'84 by a reset, and in standby mode, watch mode, subactive mode, subsleep
mode, and module stop mode.
Bit 7—Transmit Data Register Empty (TDRE): Indicates that data has been transferred from
TDR to TSR and the next serial data can be written to TDR.
Bit 7
TDRE Description
0 [Clearing conditions]
• When 0 is written in TDRE after reading TDRE = 1
• When the DTC is activated by a TXI interrupt and writes data to TDR
1 [Setting conditions] (Initial value)
• When the TE bit in SCR is 0
• When data is transferred from TDR to TSR and data can be written to TDR
Bit 6—Receive Data Register Full (RDRF): Indicates that the received data is stored in RDR.
Bit 6
RDRF Description
0 [Clearing conditions] (Initial value)
• When 0 is written in RDRF after reading RDRF = 1
• When the DTC is activated by an RXI interrupt and reads data from RDR
1 [Setting condition]
When serial reception ends normally and receive data is transferred from RSR to RDR
Note: RDR and the RDRF flag are not affected and retain their previous values when an error is
detected during reception or when the RE bit in SCR is cleared to 0.
If reception of the next data is completed while the RDRF flag is still set to 1, an overrun
error will occur and the receive data will be lost.