HD64F2149YV datasheet(428/1075 Pages) RENESAS

428 / 1075 page

Section 13 Timer Connection

Rev. 3.00 Jan 18, 2006 page 400 of 1044

REJ09B0280-0300

IVI signal

IHI signal

divided

waveform

FRC

ICRB

ICRB(1)

ICRB(2)

ICRB(3)

ICRB(4)

Figure 13.5 Timing Chart for Measurement of IVI Signal and

IHI Signal Divided Waveform Periods

13.3.4

IHI Signal and 2fH Modification

By using the timer connection FRT, even if there is a part of the IHI signal with twice the

frequency, this can be eliminated. In order for this function to operate properly, the duty cycle of

the IHI signal must be approximately 30% or less, or approximately 70% or above.

The 8-bit OCRDM contents or twice the OCRDM contents can be added automatically to the data

captured in ICRD in the FRT, and compare-matches generated at these points. The interval

between the two compare-matches is called a mask interval. A value equivalent to approximately

1/3 the IHI signal period is written in OCRDM. ICRD is set so that capture is performed on the

rise of the IHI signal.

Since the IHI signal supplied to the IHO signal selection circuit is normally set on the rise of the

IHI signal and reset on the fall, its waveform is the same as that of the original IHI signal. When

2fH modification is selected, IHI signal edge detection is disabled during mask intervals. Capture

is also disabled during these intervals.

Examples of FRT TCR settings are shown in table 13.6, and the 2fH modification timing chart is

shown in figure 13.6.

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