HD6413008F RENESAS [Renesas Technology Corp], HD6413008F Datasheet - Page 371

• Manufacturer Part Number: HD6413008F
• Description: Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series
• Manufacturer: RENESAS [Renesas Technology Corp]

12.2.3
TSR is the register that transmits serial data.
The SCI loads transmit data from TDR to TSR, then transmits the data serially from the TxD pin,
LSB (bit 0) first. After transmitting one data byte, the SCI automatically loads the next transmit
data from TDR into TSR and starts transmitting it. If the TDRE flag is set to 1 in SSR, however,
the SCI does not load the TDR contents into TSR. The CPU cannot read or write RSR directly.
12.2.4
TDR is an 8-bit register that stores data for serial transmission.
When the SCI detects that TSR is empty, it moves transmit data written in TDR from TDR into
TSR and starts serial transmission. Continuous serial transmission is possible by writing the next
transmit data in TDR during serial transmission from TSR.
The CPU can always read and write TDR. TDR is initialized to H'FF by a reset and in standby
mode.
Bit
Bit
Read/Write
Initial value
Read/Write
Transmit Shift Register (TSR)
Transmit Data Register (TDR)
R/W
⎯
7
7
1
R/W
⎯
1
6
6
R/W
⎯
5
1
5
R/W
⎯
4
1
4
Rev.4.00 Aug. 20, 2007 Page 327 of 638
R/W
⎯
3
1
3
12. Serial Communication Interface
R/W
⎯
2
2
1
REJ09B0395-0400
R/W
⎯
1
1
1
R/W
⎯
0
1
0