m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 153

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

Fig. 8.2.1 Block diagram of timer B
TIMER B
8.1 Overview, 8.2 Block description
8.1 Overview
Timer B consists of three counters (timers B0 to B2) each equipped with a 16-bit reload function. Timers
B0 to B2 have identical functions and operate independently of one other.
Timer Bi (i = 0 to 2) has three operating modes listed below.
8.2 Block description
Figure 8.2.1 shows the block diagram of timer B. Explanation of registers relevant to timer B is described
below.
8-2
TBi
(1) Timer mode
(2) Event counter mode
(3) Pulse period/Pulse width measurement mode
IN
The timer counts an internally generated count source.
The timer counts an external signal.
The timer measures an external signal’s pulse period or pulse width. In this mode, the following count
types are available:
• Count clear type
• Free-run type
Note: Only for timer B2, a clock source in the event counter mode can be selected.
Polarity selection
and edge pulse
Timer B2 clock source select bit : Bit 6 at address 63
generator
f
512
f
f
16
64
f
2
Count source select bits
•Timer
•Pulse period measurement/pulse
width measurement
Timer B2 clock source
select bit (Note)
fX
32
Event counter
7905 Group User’s Manual Rev.1.0
mode
16
Counter reset circuit
(Low-order 8 bits)
Count start register
Timer Bi reload register (16)
Timer Bi counter (16)
Data bus (odd)
Data bus (even)
(Valid in the pulse period/pulse width
measurement mode.)
(High-order 8 bits)
Timer Bi
overflow
flag
Timer Bi
interrupt
request bit