214
Bit 3—Clock Source Select 3 (CKS3): Bit 3 selects the clock source and sets pin SCK
1
as an
input or output pin.
Bit 3: CKS3
Description
0
Clock source is prescaler S, and pin SCK
1
is output pin
(initial value)
1
Clock source is external clock, and pin SCK
1
is input pin
Bits 2 to 0—Clock Select 2 to 0 (CKS2 to CKS 0): When CKS3 = 0, bits 2 to 0 select the
prescaler division ratio and the serial clock cycle.
Serial Clock Cycle
Bit 2: CKS2
Bit 1: CKS1
Bit 0: CKS0
Prescaler Division
ø = 5 MHz
ø = 2.5 MHz
0
0
0
ø/1024 (initial
value)
204.8
µ
s
409.6
µ
s
1
ø/256
51.2
µ
s
102.4
µ
s
1
0
ø/64
12.8
µ
s
25.6
µ
s
1
ø/32
6.4
µ
s
12.8
µ
s
1
0
0
ø/16
3.2
µ
s
6.4
µ
s
1
ø/8
1.6
µ
s
3.2
µ
s
1
0
ø/4
0.8
µ
s
1.6
µ
s
1
ø/2
—
0.8
µ
s
Serial Control/Status Register 1 (SCSR1)
Bit
7
6
5
4
3
2
1
0
—
SOL
ORER
—
—
—
—
STF
Initial value
1
0
0
1
1
1
0
0
Read/Write
—
R/W
R/(W)
*
—
—
—
R
R/W
Note:
*
Only a write of 0 for flag clearing is possible.
SCSR1 is an 8-bit read/write register indicating operation status and error status.
Upon reset, SCSR1 is initialized to H'9C.
Bit 7—Reserved Bit: Bit 7 is reserved; it is always read as 1, and cannot be modified.