Datasheet

Table Of Contents
Section 12 Timer F
Rev. 2.00 Jul. 04, 2007 Page 250 of 692
REJ09B0309-0200
The term of validity of "Interrupt source generation signal"
= 1 cycle of φ
W
+ waiting time for completion of executing instruction
+ interrupt time synchronized with φ
= 1/φ
W
+ ST × (1/φ) + (2/φ) (second).....(1)
ST: Executing number of execution states
Method 1 is recommended to operate for time efficiency.
Method 1
1. Prohibit interrupt in interrupt handling routine (set IENFH, IENFL to 0).
2. After program process returned normal handling, clear interrupt request flags (IRRTFH,
IRRTFL) after more than that calculated with (1) formula.
3. After reading the timer control status register F (TCSRF), clear the timer overflow flags
(OVFH, OVFL) and compare match flags (CMFH, CMFL).
4. Enable interrupts (set IENFH, IENFL to 1).
Method 2
1. Set interrupt handling routine time to more than time that calculated with (1) formula.
2. Clear interrupt request flags (IRRTFH, IRRTFL) at the end of interrupt handling routine.
3. After read timer control status register F (TCSRF), clear timer overflow flags (OVFH,
OVFL) and compare match flags (CMFH, CMFL).
All above attentions are also applied in 16-bit mode and 8-bit mode.