171
Bits 2 to 0—Clock Select L (CKSL2 to CKSL0): Bits 2 to 0 select the input to TCFL from four
internal clock signals or external event input.
Bit 2: CKSL2
Bit 1: CKSL1
Bit 0: CKSL0
Description
0
*
*
External event (TMIF). Rising or falling edge
is counted (see note).
(initial value)
1
0
0
Internal clock: ø/32
1
Internal clock: ø/16
1
0
Internal clock: ø/4
1
Internal clock: ø/2
*:
Don’t care
Note: The edge of the external event signal is selected by bit IEG3 in the IRQ edge select register
(IEGR). See 3.3.2, Interrupt Control Registers, for details on the IRQ edge select register.
Note that switching the TMIF pin function by changing bit IRQ3 in port mode register 1
(PMR1) from 0 to 1 or from 1 to 0 while the TMIF pin is at the low level may cause the timer
F counter to be incremented.
Timer Control/Status Register F (TCSRF)
Bit
7
6
5
4
3
2
1
0
OVFH
CMFH
OVIEH
CCLRH
OVFL
CMFL
OVIEL
CCLRL
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
TCSRF is an 8-bit read/write register. It is used for counter clear selection, overflow and compare
match indication, and enabling of interrupts caused by timer overflow.
Upon reset, TCSRF is initialized to H'00.
Bit 7—Timer Overflow Flag H (OVFH): Bit 7 is a status flag indicating TCFH overflow (H'FF
to H'00). This flag is set by hardware and cleared by software. It cannot be set by software.
Bit 7: OVFH
Description
0
[Clearing conditions]
(initial value)
After reading OVFH = 1, cleared by writing 0 to OVFH
1
[Setting conditions]
Set when the value of TCFH goes from H'FF to H'00