213
Register Configuration: Table 10.3 shows the SCI1 register configuration.
Table 10.3
SCI1 Registers
Name
Abbrev.
R/W
Initial Value
Address
Serial control register 1
SCR1
R/W
H'00
H'FFA0
Serial control status register 1
SCSR1
R/W
H'9C
H'FFA1
Serial data register U
SDRU
R/W
Undefined
H'FFA2
Serial data register L
SDRL
R/W
Undefined
H'FFA3
10.2.2
Register Descriptions
Serial Control Register 1 (SCR1)
Bit
7
6
5
4
3
2
1
0
SNC1
SNC0
—
—
CKS3
CKS2
CKS1
CKS0
Initial value
0
0
0
0
0
0
0
0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
SCR1 is an 8-bit read/write register for selecting the operation mode, the transfer clock source,
and the prescaler division ratio.
Upon reset, SCR1 is initialized to H'00. Writing to this register stops a transfer in progress.
Bits 7 and 6—Operation Mode Select 1, 0 (SNC1, SNC0): Bits 7 and 6 select the operation
mode.
Bit 7: SNC1
Bit 6: SNC0
Description
0
0
8-bit synchronous transfer mode
(initial value)
1
16-bit synchronous transfer mode
1
0
Continuous clock output mode*
1
1
Reserved*
2
Notes: 1. Pins SI
1
and SO
1
should be used as general input or output ports.
2. Don’t set bits SNC1 and SNC0 to 11.
Bits 5 and 4—Reserved Bits: Bits 5 and 4 are reserved: they should always be cleared to 0.