HD64F38024HV Datasheet, PDF (322/684 Pages) Renesas Technology Corp – Hardware Manual Renesas 8-Bit Single-Chip Microcomputer H8 Family/H8/300L Super Low Power Series

Section 9 Timers
When the pin function is switched and an edge is generated in the input capture input signal, if this
edge matches the edge selected by the input capture interrupt select (IIEGS) bit, the interrupt
request flag will be set to 1. The interrupt request flag should therefore be cleared to 0 before use.
Figure 9.15 shows the procedure for port mode register manipulation and interrupt request flag
clearing. When switching the pin function, set the interrupt-disabled state before manipulating the
port mode register, then, after the port mode register operation has been performed, wait for the
time required to confirm the input capture input signal as an input capture signal (at least two
system clocks when the noise canceler is not used; at least five sampling clocks when the noise
canceler is used), before clearing the interrupt enable flag to 0. There are two ways of preventing
interrupt request flag setting when the pin function is switched: by controlling the pin level so that
the conditions shown in tables 9.14 and 9.15 are not satisfied, or by setting the opposite of the
generated edge in the IIEGS bit in TMG.
Set I bit in CCR to 1
Manipulate port mode register
*_{TMIG confirmation time}
Clear interrupt request flag to 0
Disable interrupts. (Interrupts can also be disabled by
manipulating the interrupt enable bit in interrupt enable
register 2.)
After manipulating the port mode register, wait for the
TMIG confirmation time^* (at least two system clocks when
the noise canceler is not used; at least five sampling
clocks when the noise canceler is used), then clear the
interrupt enable flag to 0.
Clear I bit in CCR to 0
Enable interrupts
Figure 9.15 Port Mode Register Manipulation and Interrupt Enable Flag Clearing
Procedure
Rev. 8.00 Mar. 09, 2010 Page 300 of 658
REJ09B0042-0800