132
TCSR Timer Control/Status Register
WDT
7
UDF
0
R/W
6
EWE
0
R/(W)*
5
—
1
R
4
HLT
0
R/W
3
—
1
R
0
CS0
0
R/W
2
—
1
R
1
CS1
0
R/W
Bit
Initial value
Read/Write
Clock Select 1 and 0
0
1
0
1
0
1
CLK/32
CLK/64
CLK/128
CLK/256
Halt Flag
0
1
Normal operation
On-chip functions stop
ECR Write Enable
0
1
[Clearing condition]
When EEPMOV instruction execution ends
[Setting conditon]
When 1 is written to this bit while it is 0
Underflow Flag
0
1
[Clearing condition]
When RTE instruction is executed while UDF = 1
[Setting conditon]
When TCNT underflow occurs (H'00
→
H'FF)
Note: Only 1 can be written to bit 6 to set the flag.
TCNT Timer Counter
WDT
Bit
Initial value
Read/Write
Timer count
7
1
R/W
6
1
R/W
5
1
R/W
4
1
R/W
3
1
R/W
0
1
R/W
2
1
R/W
1
1
R/W