m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 174

• Manufacturer Part Number: m37905
• Description: Mitsubishi 16-bit Single-chip Microcomputer 7700 Family / 7900 Series
• Manufacturer: Renesas Electronics Corporation.

Table 8.5.3 Relationship between measurement mode select bits and pulse period/pulse width measurements
8.5.2 Operation in pulse period/pulse width measurement mode
b3
(1) Pulse period/pulse width measurement
0
0
1
Note: No timer Bi interrupt request occurs when the first valid edge is input after the counter starts counting.
Note: No timer Bi interrupt request occurs when the first valid edge is input after the counter starts counting.
When counter clear type is selected
When free-run type is selected
is detected. (Refer to section “(1) Pulse period/Pulse width measurement.”)
The interrupt request bit remains set to “1” until the interrupt request is accepted or until the interrupt
request bit is cleared to “0” by software.
is detected. (Refer to section “(1) Pulse period/Pulse width measurement.”)
The interrupt request bit remains set to “1” until the interrupt request is accepted or until the interrupt
request bit is cleared to “0” by software.
The counter continues counting with the counter value kept.
clearing the counter value to “0000
The timer Bi interrupt request bit is set to “1” when the counter value is cleared to “0000
When the count start bit is set to “1,” the counter starts counting of the count source.
The counter value is transferred to the reload register when a valid edge of the measurement pulse
The counter value is cleared to “0000
The timer repeats operations
When the count start bit is set to “1,” the counter starts counting of the count source.
The counter value is transferred to the reload register when a valid edge of the measurement pulse
The timer Bi interrupt request bit is set to “1” after the transfer in
When a counter overflow occurs, the timer Bi overflow flag is set to “1,” and counting continues after
The timer repeats operations
The measurement mode select bits (bits 3 and 2 at addresses 5B
pulse period of an external signal is measured or its pulse width is done. Table 8.5.3 lists the
relationship between the measurement mode select bits and the pulse period/pulse width measurements.
Make sure that the measurement pulse interval from the falling edge to the rising edge, and vice
versa are two cycles of the count source or more. Additionally, use software to identify whether the
measurement result indicates the “H” level width or the “L” level width.
b2
0
1
0
Pulse period measurement
Pulse width measurement
Pulse period/Pulse width measurement
to
to
7905 Group User’s Manual Rev.1.0
16
.” At this time, the timer Bi interrupt request bit does not change.
8.5 Pulse period/pulse width measurement mode
16
above.
above.
” after the transfer in
From falling edge to falling edge (Falling edges)
From rising edge to rising edge (Rising edges)
From falling edge to rising edge, and vice versa
(Falling and rising edges)
Measurement interval (Valid edges)
, and the counter continues counting.
16
(Note).
and 5D
16
) specify whether the
TIMER B
16
” in
(Note).
8-23