m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 164

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

mode. Figure 8.4.1 shows the structures of the timer Bi register and the timer Bi mode register in the event
counter mode.
Count source
Count operation
Division ratio
Count start condition
Count stop condition
Interrupt request occurrence timing
TBi
Read from timer Bi register
Write to timer Bi register
8.4 Event counter mode
In this mode, the timer counts an external signal. Table 8.4.1 lists the specifications of the event counter
Table 8.4.1 Specifications of event counter mode
Notes 1: Only for timer B2, fX
IN
pin’s function
2: When fX
I/O port pin or as I/O pins of other internal peripheral devices, which are multiplexed.
Item
32
is selected as the count source in timer B2, the TB2
32
can be selected.
•External signal input to the TBi
•The count source’s valid edge can be selected from the falling edge,
•Countdown
•When a counter underflow occurs, reload register’s contents are
When the count start bit is set to “1.”
When the count start bit is cleared to “0.”
When the counter underflow occurs.
Count source input pin (Note 2)
Counter value can be read out.
the rising edge, and both of the falling and rising edges by software.
reloaded, and counting continues.
(n + 1)
7905 Group User’s Manual Rev.1.0
While counting is stopped
When a value is written to the timer Bi register, it is written to both
of the reload register and counter.
While counting is in progress
When a value is written to the timer Bi register, it is written only to the
reload register. (Transferred to the counter at the next reload timing.)
1
n: Timer Bi register’s set value
Specifications
IN
IN
pin, or fX
pin can be used as a programmable
8.4 Event counter mode
32
(Note 1)
TIMER B
8-13