Renesas 7700 FAMILY, User Manual

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TIMER B
6–20 7751 Group User’s Manual
6.5 Pulse period/pulse width measurement mode
Fig. 6.5.1 Structures of timer Bi mode register and timer Bi register in pulse period/pulse width
measurement mode
b7 b0 b7 b0
(b15) (b8)
Timer B0 register (Addresses 51
16
, 50
16
)
Timer B1 register (Addresses 53
16
, 52
16
)
Timer B2 register (Addresses 55
16
, 54
16
)
Functions Bit
At reset
RW
15 to 0 The measurement result of pulse period or
pulse width is read out.
Undefined
RO
Measurement mode select bits
1
Operating mode select bits
Bit name Functions
b7 b6 b5 b4 b3 b2 b1 b0
Timer Bi mode register (i = 0 to 2) (Addresses 5B
16
to 5D
16
)
1 0 : Pulse period/Pulse width
measurement mode
7
0 0 : f
2
/f
4
0 1 : f
16
/f
32
1 0 : f
64
/f
128
1 1 : f
512
/f
1024
b7 b6
Count source select bits
b1 b0
b3 b2
Nothing is assigned.
0 1
0 0 : Pulse period measurement
(Interval between falling edges
of measurement pulse)
0 1 : Pulse period measurement
(Interval between rising edges
of measurement pulse)
1 0 : Pulse width measurement
(Interval from falling edge to rising
edge, and from rising edge to falling
edge of measurement pulse)
1 1 : Not selected
Bit At reset
Undefined
0
RW
4
0
2
3
6
RW
RW
RW
RW
–
RW
RW
5
0
0
0
Timer Bi overflow flag
(Note) 0 : No overflow
1 : Overflow
Undefined RO
0
0
Note: The timer Bi overflow flag is cleared to “0” by writing to the timer Bi mode register with the
count start bit = “1.”