Datasheet

Table Of Contents
Section 13 Serial Communication Interface
Page 396 of 846 REJ09B0140-0900 Rev. 9.00
Sep 16, 2010
H8S/2215 Group
13.3.7 Serial Status Register (SSR)
SSR is a register containing status flags of the SCI and multiprocessor bits for transfer. 1 cannot
be written to flags TDRE, RDRF, ORER, PER, and FER; they can only be cleared. Some bits in
SSR have different functions in normal mode and smart card interface mode.
Normal Serial Communication Interface Mode (When SMIF in SCMR is 0)
Bit Bit Name Initial Value R/W Description
7 TDRE 1 R/(W)
*
1
Transmit Data Register Empty
Displays whether TDR contains transmit data.
[Setting conditions]
When the TE bit in SCR is 0
When data is transferred from TDR to TSR and data
can be written to TDR
[Clearing conditions]
When 0 is written to TDRE after reading TDRE = 1
*
3
When the DMAC or the DTC
*
2
is activated by a TXI
interrupt request and writes data to TDR
6 RDRF 0 R/(W)
*
1
Receive Data Register Full
Indicates that the received 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
*
3
When the DMAC or the DTC
*
2
is activated by an RXI
interrupt and transferred data from RDR
RDR and the RDRF flag are not affected and retain their
previous values when the RE bit in SCR is cleared to 0.
The RDRF flag is not affected and retains their previous
values when the RE bit in SCR is cleared to 0.