![](http://datasheet.mmic.net.cn/330000/MB90T678_datasheet_16438155/MB90T678_52.png)
MB90670/675 Series
52
6. 24-bit Free-run Timer
The 24-bit free-run timer is a 24-bit up counter for counting up in synchronization to divided-by-3 or divided-by-
4 of the machine clock, in which an interrupt factor can be selected from the overflow interrupt and four types
of timer intermediate bit interrupt to be operated as an interval timer.
The free-run timer can be used to generating reference timing signals for the input capture (ICU) and output
compare (OCU).
(1) Register Configuration
bit 7. . . .. . . . . . .. .
Free-run timer control register upper digits (TCCR : H)
bit 15
Address
—
—
RESV RESV
RESV
RESV RESV
PR0
(TCCR : L)
—
—
R/W
R/W
R/W
R/W
R/W
R/W
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
Initial value
- -111111
B
bit 1. . . . .. . . . . . ..
Free-run timer control register lower digits (TCCR : L)
Address
CLR
STP
(TCCR : H)
W
W
R/W
R/W
R/W
R/W
R/W
R/W
bit 7
bit 6
bit 5
bit 4
Initial value
11000000
B
IVFE
IVF
TIME
TIM
TIS0
TIS1
bit 3
bit 2
bit 1
bit 0
Free-run timer upper data register (TCRH)
Address
000056
H
000057
H
R
Free-run timer lower data register (TCRL)
Address
000054
H
000055
H
R
bit 15
Initial value
00000000
B
00000000
B
bit 14bit 13bit 12bit 11bit 10 bit 9 bit 8 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R/W : Readable and writable
R : Read only
W : Write only
— : Unused
000051
H
000050
H
—
—
—
—
—
—
—
—
T23 T22 T21 T20 T19 T18 T17 T16
bit 15
Initial value
00000000
B
00000000
B
bit 14bit 13bit 12bit 11bit 10 bit 9 bit 8 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
T15 T14 T13 T12 T11 T10
T9
T8
T7
T6
T5
T4
T3
T2
T1
T0