m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 170

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

Timer Bi overflow flag: This bit is used to identify the source of an interrupt request occurrence.
Notes 1: No interrupt request occurs when the first valid edge is input after the counter starts counting.
8.5 Pulse period/Pulse width measurement mode
In this mode, the timer measures an external signal’s pulse period or pulse width. Tables 8.5.1 and 8.5.2
list the specifications of the pulse period/pulse width measurement mode. Figure 8.5.1 shows the structures
of the timer Bi register and timer Bi mode register in the pulse period/pulse width measurement mode.
Table 8.5.1 Specifications of pulse period/pulse width measurement mode (when counter clear type is selected)
Count source f
Count operation
Count start condition
Count stop condition
Interrupt request occurrence timing
TBi
Read from timer Bi register
Write to timer Bi register
(1) Pulse period measurement
(2) Pulse width measurement
IN
pin’s function
The timer measures the pulse period of the external signal that is input to the TBi
The timer measures the pulse width (“L” level and “H” level widths) of the external signal that is input
to the TBi
2: When using timer B2, make sure that the timer B2 clock source select bit (see Figure 8.4.2.) to
3: The value read out from the timer Bi register is undefined in the period after the counter starts
“0.”
counting until the second valid edge is input.
i
Item
IN
pin.
f
When the count start bit is set to “1.”
When the count start bit is cleared to “0.”
Measurement pulse input pin (Note 2)
The value obtained by reading the timer Bi register is the reload
register’s contents (Measurement result) (Note 3).
Invalid
2
, f
7905 Group User’s Manual Rev.1.0
Countup
Counter value is transferred to the reload register at valid edge of
measurement pulse, and counting continues after clearing the counter
value to “0000
When a valid edge of measurement pulse is input (Note 1).
When a counter overflow occurs (The timer Bi overflow flag is set
to “1” simultaneously.)
16
, f
8.5 Pulse period/Pulse width measurement mode
64
, or f
512
16
.”
Specifications
IN
TIMER B
pin.
8-19