Rev. 1.0, 02/00, page 715 of 1141
The 16-bit counter in the REC-CTL circuit continues counting on a clock derived by dividing the
system clock
φ
s (= f
OSC
/2) by 4. The counter is cleared on the rise of REF30X in record mode, and
on the rise of PB-CTL in rewrite mode. REC-CTL match detection is carried out by comparing
the counter value with each RCDR value.
RCDR1 to RCDR5 can be written to by software at all times. If RCDR is changed before the
respective match detection is performed, match detection is performed using the new value. The
value changed after match detection becomes valid on the rise of REF30X following the change.
Figure 26.61 shows examples of RCDR change timing.
REF30X
REC-CTL
RCDR1 RCDR2
RCDR1
1 pulse (Short)
0 pulse (Short)
Rewritten 0 pulse
(Short)
RCDR1
RCDR1
Counter
RCDR4
RCDR2
RCDR1
RCDR4
RCDR4
RCDR4
Interval in which
RCDR4 can be
written to
Figure 26.61 Example of RCDR Change Timing (Example Showing RCDR4)