h8s-2649 Renesas Electronics Corporation., h8s-2649 Datasheet - Page 392

• Manufacturer Part Number: h8s-2649
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

Section 13 Serial Communication Interface (SCI)
13.3
The SCI has the following registers for each channel. The serial mode register (SMR), serial status
register (SSR), and serial control register (SCR) are described separately for normal serial
communication interface mode and smart card interface mode because their bit functions differ in
part.
• Receive shift register (RSR)
• Receive data register (RDR)
• Transmit data register (TDR)
• Transmit shift register (TSR)
• Serial mode register (SMR)
• Serial control register (SCR)
• Serial status register (SSR)
• Smart card mode register (SCMR)
• Bit rate register (BRR)
13.3.1
RSR is a shift register that is used to receive serial data input to the RxD pin and convert it into
parallel data. When one byte of data has been received, it is transferred to RDR automatically.
RSR cannot be directly accessed by the CPU.
13.3.2
RDR is an 8-bit register that stores received data. When the SCI has received one byte of serial
data, it transfers the received serial data from RSR to RDR, where it is stored. After this, RSR is
receive-enabled. As RSR and RDR function as a double buffer in this way, continuous receive
operations are possible. After confirming that the RDRF bit in SSR is set to 1, read RDR only
once. RDR cannot be written to by the CPU.
Rev. 2.00 Dec. 05, 2005 Page 354 of 724
REJ09B0200-0200
Register Descriptions
Receive Shift Register (RSR)
Receive Data Register (RDR)