m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 180

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

[Precautions for pulse period/pulse width measurement mode]
1. When the counter clear type is selected, a timer Bi interrupt request is generated by one of the following
3. After reset, the timer Bi overflow flag is undefined. When a value is written to the timer Bi mode register
4. An undefined value is transferred to the reload register at the first valid edge input after the count start.
5. The counter value at count start is undefined. Therefore, there is a possibility that a counter overflow
6. If the contents of the measurement mode select bits are changed after the count start, the timer Bi
7. When using timer B2, be sure to clear the timer B2 clock source select bit (bit 6 at address 63
2. When the free-run type is selected, the timer Bi interrupt request is generated only by the valid edge input
8. If the input signal to the TBi
When an overflow generates an interrupt request, the timer Bi overflow flag will be set to “1.”
after the next count timing of the count source with the count start bit = “1,” this flag will be cleared to
“0.”
In this case, no timer Bi interrupt request will occur.
occurs immediately after the counting starts. In this case, the timer Bi overflow flag becomes “1”; and
when the counter clear type is selected, a timer Bi interrupt request is generated.
interrupt request bit is set to “1.” When the value, which has been set in these bits before, are written
again, the timer Bi interrupt request bit will not change.
sources:
of the pulse to be measured.
perform the exact measurement. We recommend to verify, by software, that the measurement values are
within a constant range.
Valid edge input of measured pulse
Counter overflow
[Precautions for pulse period/pulse width measurement mode]
IN
pin is affected by noise, etc., there is a possibility that the counter cannot
7905 Group User’s Manual Rev.1.0
TIMER B
16
) to “0.”
8-29