How-To Guide

Table Of Contents
R01UH0823EJ0110 Rev.1.10 Page 977 of 1852
Nov 30, 2020
RX23W Group 33. Serial Communications Interface (SCIg, SCIh)
33.2 Register Descriptions
33.2.1 Receive Shift Register (RSR)
The RSR register is a shift register which is used to receive serial data input from the RXDn pin and converts it into
parallel data.
When one frame of data has been received, it is automatically transferred to the RDR register.
The RSR register cannot be directly accessed by the CPU.
33.2.2 Receive Data Register (RDR)
The RDR register is an 8-bit register that stores receive data.
When one frame of serial data has been received, the received serial data is transferred from the RSR register to the RDR
register. Then the RSR register can receive the next data.
Since the RSR and RDR registers function as a double buffer in this way, continuous receive operations can be
performed.
Read the RDR register only once after a receive data full interrupt (RXI) has occurred. Note that if next one frame of data
is received before reading receive data from the RDR register, an overrun error occurs.
The RDR register cannot be written to by the CPU.
Address(es): SCI1.RDR 0008 A025h, SCI5.RDR 0008 A0A5h, SCI8.RDR 0008 A105h, SCI12.RDR 0008 B305h
b7 b6 b5 b4 b3 b2 b1 b0
Value after reset:
00000000