h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 455

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

15.2.7
Note:
SSR is an 8-bit register containing status flags that indicate the operating status of the SCI, and
multiprocessor bits.
SSR can be read or written to by the CPU at all times. However, 1 cannot be written to flags
TDRE, RDRF, ORER, PER, and FER. Also note that in order to clear these flags they must be
read as 1 beforehand. The TEND flag and MPB flag are read-only flags and cannot be modified.
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
0
1
Bit
Initial value
Read/Write
* Only 0 can be written, to clear the flag.
Serial Status Register (SSR)
Description
[Clearing conditions]
[Setting 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
When the TE bit in SCR is 0
When data is transferred from TDR to TSR and data can be written to TDR
R/(W) *
TDRE
7
1
R/(W) *
RDRF
6
0
R/(W) *
ORER
5
0
Section 15 Serial Communication Interface (SCI, IrDA)
R/(W) *
FER
4
0
Rev. 4.00 Jun 06, 2006 page 401 of 1004
R/(W) *
PER
3
0
TEND
R
2
1
MPB
REJ09B0301-0400
R
1
0
(Initial value)
MPBT
R/W
0
0