Datasheet

Table Of Contents
Section 18 Serial Communication Interface 4 (SCI4)
Rev. 2.00 Jul. 04, 2007 Page 421 of 692
REJ09B0309-0200
18.3.3 Transmit Data Register 4 (TDR4)
TDR4 is an 8-bit register that stores data for serial transmission. When the SCI4 detects that SR4
is empty, it transfers the transmit data written in TDR4 to SR4 and starts serial transmission. If the
next transmit data is written to TDR4 while serial data in SR4 is being transmitted, continuous
serial transmission is possible. TDR4 can be read from or written to by the CPU at any time.
TDR4 is initialized to H'FF.
18.3.4 Receive Data Register 4 (RDR4)
RDR4 is an 8-bit register that stores receive data. When the SCI4 has received one byte of serial
data, it transfers the received serial data from SR4 to RDR4, where it is stored. Then receive
operation is completed. After this, SR4 is receive-enabled. RDR4 cannot be written to by the CPU.
RDR4 is initialized to H'00.
18.3.5 Shift Register 4 (SR4)
SR4 is a register that receives or transmits serial data. SR4 cannot be directly read from or written
to by the CPU.