Serial Mode Register (Smr) - Hitachi H8S/2646 Hardware Manual

13.2.5

Serial Mode Register (SMR)

Bit :
C/A
Initial value :
R/W : R/W
SMR is an 8-bit register used to set the SCI's serial transfer format and select the baud rate
generator clock source.
SMR can be read or written to by the CPU at all times.
SMR is initialized to H'00 by a reset and in hardware standby mode.
Bit 7—Communication Mode (C/A): Selects asynchronous mode or clocked synchronous mode
as the SCI operating mode.
Bit 7
C/A Description
0 Asynchronous mode
1 Clocked synchronous mode
Bit 6—Character Length (CHR): Selects 7 or 8 bits as the data length in asynchronous mode. In
clocked synchronous mode, a fixed data length of 8 bits is used regardless of the CHR setting.
Bit 6
CHR Description
0 8-bit data
1 7-bit data*
Note: * When 7-bit data is selected, the MSB (bit 7) of TDR is not transmitted, and it is not possible
to choose between LSB-first or MSB-first transfer.
438
7 6 5
CHR PE
0 0 0
R/W R/W
4 3
O/E STOP MP
0 0
R/W R/W R/W
2 1 0
CKS1 CKS0
0 0 0
R/W R/W
(Initial value)
(Initial value)