p2125vps20 Renesas Electronics Corporation., p2125vps20 Datasheet - Page 360

• Manufacturer Part Number: p2125vps20
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 15 Serial Communication Interface (SCI)
15.3.7
SSR is a register containing status flags of the SCI and multiprocessor bits for transfer. TDRE,
RDRF, ORER, PER, and FER can only be cleared.
Rev. 1.00 Sep. 21, 2006 Page 322 of 658
REJ09B0310-0100
Bit
7
6
5
Bit Name
TDRE
RDRF
ORER
Serial Status Register (SSR)
Initial
Value
1
0
0
R/W
R/(W)* Transmit Data Register Empty
R/(W)* Receive Data Register Full
R/(W)* Overrun Error
Description
Indicates whether TDR contains transmit data.
[Setting conditions]
•
•
[Clearing conditions]
•
•
Indicates that receive data is stored in RDR.
[Setting condition]
•
[Clearing conditions]
•
•
The RDRF flag is not affected and retains its previous
value when the RE bit in SCR is cleared to 0.
[Setting condition]
•
[Clearing condition]
•
When the TE bit in SCR is 0
When data is transferred from TDR to TSR and TDR
is ready for data write
When 0 is written to TDRE after reading TDRE = 1
When a TXI interrupt request is issued allowing the
DTC to write data to TDR
When serial reception ends normally and receive
data is transferred from RSR to RDR
When an RXI interrupt request is issued allowing the
DTC to read data from RDR
When the next data is received while RDRF = 1
When 0 is written to ORER after reading ORER = 1
When 0 is written to RDRF after reading RDRF = 1