M30622MA-XXXFP RENESAS [Renesas Technology Corp], M30622MA-XXXFP Datasheet - Page 335

• Manufacturer Part Number: M30622MA-XXXFP
• Description: 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY
• Manufacturer: RENESAS [Renesas Technology Corp]

Timer B
320
Operation
Note
Figure 2.3.8. Operation timing of pulse period measurement mode
2.3.4 Operation of Timer B (pulse period measurement mode)
In pulse period/pulse width measurement mode, choose functions from those listed in Table 2.3.3. Op-
erations of the circled items are described below. Figure 2.3.8 shows the operation timing, and Figure
2.3.9 shows the set-up procedure.
Count source
Measurement pulse
Reload register
transfer timing
Count start flag
Timer Bi interrupt
request bit
Timing at which counter
reaches “0000
Timer Bi overflow flag
Table 2.3.3. Choosed functions
(1) Setting the count start flag to “1” causes the counter to start counting the count source.
(2) If a measurement pulse changes from “H” to “L”, the value of the counter goes to “0000
(3) If a measurement pulse changes from “H” to “L” again, the value of the counter is transferred
• The timer Bi interrupt request bit goes to “1” when an effective edge of a measurement pulse is
• The value of the counter at the beginning of a count is indeterminate. Thus there can be in-
• The timer Bi overflow flag goes to “0” if timer Bi mode register is written to when the count start
Count source
Measurement
mode
Measurement of pulse time interval from falling edge to falling edge
input or timer Bi is overflowed. The factor of interrupt request can be determined by use of the
timer Bi overflow flag within the interrupt routine.
stances in which the timer Bi overflow flag goes to “1” immediately after a count is performed.
flag is “1”. This flag cannot be set to “1” by software.
and measurement is started. In this instance, an indeterminate value is transferred to the
reload register. The timer Bi interrupt request does not generate.
to the reload register, and the timer Bi interrupt request bit goes to “1”. Then the value of the
counter becomes “0000
Item
16
Note 1: Counter is initialized at completion of measurement.
Note 2: Timer has overflowed.
”
counter
O
O
“H”
“0”
“L”
“1”
“0”
“0”
“1”
“1”
Internal count source (f
Pulse period measurement (interval between measurement pulse falling edge to falling edge)
Pulse period measurement (interval between measurement pulse rising edge to rising edge)
Pulse width measurement (interval between measurement pulse falling edge to rising edge,
(1) Start count
16
”, and the measurement is started again.
Cleared to “0” when interrupt request is accepted, or cleared by software
(Note 1)
1
/ f
8
and between rising edge to falling edge)
/ f
32
(2) Start measurement
/ fc
Transfer
(indeterminate value)
32
)
Set-up
(Note 1)
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
(3) Start measurement again
Transfer
(measured value)
(Note 2)
Mitsubishi microcomputers
M16C / 62 Group
16
”,