h8s-2646 Renesas Electronics Corporation., h8s-2646 Datasheet - Page 1109

• Manufacturer Part Number: h8s-2646
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

TCSR1—Timer Control/Status Register 1
Note: * Only a 0 may be written to this bit to clear the flag.
Overflow Flag
0
1
Bit
Initial value
Read/Write
Timer Mode Select
[Clearing conditions]
[Setting condition]
When TCNT overflows (changes from H'FF to H'00)
(When internal reset request generation is selected in watchdog timer mode,
OVF is cleared automatically by the internal reset)
0
1
TCSR1 register differs from other registers in being more difficult to write to.
For details see section 12.2.4, Notes on Register Access.
Cleared when 0 is written to the TME bit (Only applies to WDT1)
Cleared by reading TCSR when OVF = 1, then write 0 in OVF
Timer Enable
Interval timer mode: WDT1 requests an interval timer interrupt (WOVI) from the CPU when the TCNT overflows
Watchdog timer mode: WDT1 requests a reset or an NMI interrupt from the CPU when the TCNT overflows
0
1
Prescaler Select
TCNT is initialized to H'00 and halted
TCNT counts
0
1
Reset or NMI
The TCNT counts frequency-
division clock pulses of the
The TCNT counts frequency-
division clock pulses of the
0
1
based prescaler (PSM)
SUB-based prescaler (PSS)
R/(W) *
NMI request
Internal reset request
OVF
7
0
WT/IT
R/W
6
0
TME
R/W
5
0
Clock Select 2 to 0
Note: * An overflow period is the time interval between the start of
PSS
0
1
CKS2
PSS
R/W
counting up from H'00 on the TCNT and the occurrence of a
TCNT overflow.
0
0
1
1
4
0
H'FFA2(W), H'FFA2(R)
CKS1 CKS0
0
0
Rev. 5.00 Sep 22, 2005 page 1083 of 1136
1
0
1
1
0
1
RST/NMI
R/W
3
0
0
0
1
0
1
0
1
0
1
1
0
1
0
1
0
1
/2
/64
/128
/512
/2048
/8192
/32768
/131072
SUB/2
SUB/4
SUB/8
SUB/16
SUB/32
SUB/64
SUB/128
SUB/256
Appendix B Internal I/O Register
Clock
CKS2
R/W
2
0
(where
CKS1
(where
R/W
Overflow Period *
1
0
REJ09B0257-0500
SUB = 32.768 kHz)
25.6 µs
819.2 µs
1.6 ms
6.6 ms
26.2 ms
104.9 ms
419.4 ms
1.68 s
15.6 ms
31.3 ms
62.5 ms
125 ms
250 ms
500 ms
1 s
2 s
= 20 MHz)
CKS0
R/W
0
0
WDT1