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.
(1) Timer mode
The timer counts an internally generated count source.
(2) Event counter mode
The timer counts an external signal.
(3) Pulse period/Pulse width measurement mode
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
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.
Data bus (odd)
Count source select bits
f2
f
f
16
64
512
Data bus (even)
(Low-order 8 bits)
(High-order 8 bits)
f
•Timer
•Pulse period measurement/pulse
width measurement
Timer Bi reload register (16)
Timer Bi counter (16)
Event counter
mode
Polarity selection
and edge pulse
generator
Timer Bi
interrupt
request bit
TBiIN
fX32
Timer B2 clock source
select bit (Note)
Timer Bi
overflow
flag
Count start register
Counter reset circuit
(Valid in the pulse period/pulse width
measurement mode.)
Timer B2 clock source select bit : Bit 6 at address 6316
Note: Only for timer B2, a clock source in the event counter mode can be selected.
Fig. 8.2.1 Block diagram of timer B
7906 Group User’s Manual Rev.2.0
8-2
RENESAS [ RENESAS TECHNOLOGY CORP ]
