Serial Mode Register (Smr) - Renesas H8S Series Hardware Manual

14.3.5

Serial Mode Register (SMR)

SMR is used to set the SCI's serial transfer format and select the baud rate generator clock source.
Some bit functions of SMR differ between normal serial communication interface mode and Smart
Card interface mode.
Normal Serial Communication Interface Mode (When SMIF in SCMR is 0)
Bit Bit Name Initial Value
7 C/A 0
6 CHR 0
5 PE 0
4 O/E 0
3 STOP 0
Section 14 Serial Communication Interface (SCI)
R/W Description
R/W Communication Mode
0: Asynchronous mode
1: Clocked synchronous mode
R/W Character Length (enabled only in asynchronous
mode)
0: Selects 8 bits as the data length.
1: Selects 7 bits as the data length. LSB-first is fixed
and the MSB of TDR is not transmitted in
transmission.
In clocked synchronous mode, a fixed data length of 8
bits is used.
R/W Parity Enable (enabled only in asynchronous mode)
When this bit is set to 1, the parity bit is added to
transmit data before transmission, and the parity bit is
checked in reception. For a multiprocessor format,
parity bit addition and checking are not performed
regardless of the PE bit setting.
R/W Parity Mode (enabled only when the PE bit is 1 in
asynchronous mode)
0: Selects even parity.
1: Selects odd parity.
R/W Stop Bit Length (enabled only in asynchronous mode)
Selects the stop bit length in transmission.
0: 1 stop bit
1: 2 stop bits
In reception, only the first stop bit is checked. If the
second stop bit is 0, it is treated as the start bit of the
next transmit character.
Rev. 6.00 Mar 15, 2006 page 317 of 570
REJ09B0211-0600