Ivi Signal Fall Modification And Ihi Synchronization; Figure 13.11 2Fh Modification Timing Chart - Renesas H8S/2437 Hardware Manual

IHI signal
(without 2fH
modification)
IHI signal
(with 2fH
modification)
Mask interval
ICRD + OCRDM × 2
ICRD + OCRDM
FRC
ICRD
13.4.5

IVI Signal Fall Modification and IHI Synchronization

By using the timer connection and TMR1, the fall of the IVI signal can be shifted backward by the
specified number of IHI signal waveforms. Also, the fall of the IVI signal can be synchronized
with the rise of the IHI signal. Figure 13.12 shows a block diagram for IVI signal fall modification
and IHI signal operation.
To measure of the 8-bit timer divided waveform period, TCNT of the TMR1 is set to count
external clock (IHI signal) pulses, and to be cleared on the rising edge of the external reset signal
(inverse of the IVI signal). The number of IHI signal pulses until the fall of the IVI signal is
written to TOCRB.
Since the IVI signal supplied to the IVO signal selection circuit is normally set on the rise of the
IVI signal and reset on the fall, its waveform is the same as that of the original IVI signal. When
fall modification is selected, a reset is performed on a TCORB compare-match of the TMR1.
The fall of the waveform generated in this way can be synchronized with the rise of the IHI signal,
regardless of whether or not fall modification is selected.

Figure 13.11 2fH Modification Timing Chart

Rev. 1.00, 09/03, page 389 of 704