How-To Guide

Table Of Contents
R01UH0823EJ0110 Rev.1.10 Page 981 of 1852
Nov 30, 2020
RX23W Group 33. Serial Communications Interface (SCIg, SCIh)
33.2.7 Serial Mode Register (SMR)
Some bits in the SMR register have different functions in smart card interface mode and non-smart card interface mode.
(1) Non-Smart Card Interface Mode (SCMR.SMIF = 0)
Note 1. n is the decimal notation of the value of n in the BRR register (refer to section 33.2.11, Bit Rate Register (BRR)).
Note 2. In other than asynchronous mode, this bit setting is invalid and a fixed data length of 8 bits is used.
Note 3. LSB first is fixed and the MSB (bit 7) in the TDR register is not transmitted in transmission.
Note 4. Writable only when the SCR.TE bit is 0 and the SCR.RE bit is 0 (both serial transmission and reception are disabled).
CKS[1:0] Bits (Clock Select)
These bits select the clock source for the on-chip baud rate generator.
For the relation between the settings of these bits and the baud rate, refer to
section 33.2.11, Bit Rate Register (BRR).
MP Bit (Multi-Processor Mode)
Disables/enables the multi-processor communications function. The settings of the PE bit and PM bit are invalid in
multi-processor mode.
Address(es): SCI1.SMR 0008 A020h, SCI5.SMR 0008 A0A0h, SCI8.SMR 0008 A100h, SCI12.SMR 0008 B300h
b7 b6 b5 b4 b3 b2 b1 b0
CM CHR PE PM STOP MP CKS[1:0]
Value after reset:
00000000
Bit Symbol Bit Name Description R/W
b1, b0 CKS[1:0] Clock Select
b1 b0
0 0: PCLK (n = 0)*
1
0 1: PCLK/4 (n = 1)*
1
1 0: PCLK/16 (n = 2)*
1
1 1: PCLK/64 (n = 3)*
1
R/W*
4
b2 MP Multi-Processor Mode (Valid only in asynchronous mode)
0: Multi-processor communications function is disabled
1: Multi-processor communications function is enabled
R/W*
4
b3 STOP Stop Bit Length (Valid only in asynchronous mode)
0: 1 stop bit
1: 2 stop bits
R/W*
4
b4 PM Parity Mode (Valid only when the PE bit is 1)
0: Selects even parity
1: Selects odd parity
R/W*
4
b5 PE Parity Enable (Valid only in asynchronous mode)
When transmitting
0: Parity bit addition is not performed
1: The parity bit is added
When receiving
0: Parity bit checking is not performed
1: The parity bit is checked
R/W*
4
b6 CHR Character Length (Valid only in asynchronous mode*
2
)
Selects in combination with the SCMR.CHR1 bit.
CHR1 CHR
0 0: Transmit/receive in 9-bit data length
0 1: Transmit/receive in 9-bit data length
1 0: Transmit/receive in 8-bit data length (initial value)
1 1: Transmit/receive in 7-bit data length*
3
R/W*
4
b7 CM Communications Mode 0: Asynchronous mode or simple I
2
C mode
1: Clock synchronous mode or simple SPI mode
R/W*
4