4518 Datasheet, PDF (41/160 Pages) Renesas Technology Corp – SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

4518 Group
• Prescaler, Timer 1, Timer 2 and Timer 3 count start timing and
count time when operation starts
Count starts from the first rising edge of the count source (2) af-
ter Prescaler, Timer 1, Timer 2 and Timer 3 operations start (1).
Time to first underflow (3) is shorter (for up to 1 period of the
count source) than time among next underflow (4) by the timing
to start the timer and count source operations after count starts.
(2)
Count Source
Timer value 3 2 1 0 3 2 1 0 3 2
Timer Underflow signal
(3)
(4)
(1) Timer Start
Fig. 29 Timer count start timing and count time when opera-
tion starts (Prescaler, Timer 1, Timer 2 and Timer 3)
• Timer 4 count start timing and count time when operation starts
Count starts from the rising edge (2) after the first falling edge of
the count source, after Timer 4 operations start (1).
Time to first underflow (3) is different from time among next un-
derflow (4) by the timing to start the timer and count source
operations after count starts.
(2)
Count Source
Timer Value
32 1 0 3 2 1 0 3
Timer Underflow Signal
(3)
(4)
(1) Timer Start
Fig. 30 Timer count start timing and count time when opera-
tion starts (Timer 4)
Rev.3.01 2005.06.15 page 41 of 157
REJ03B0008-0301