HD64F2145 datasheet(354/829 Pages) RENESAS

354 / 829 page

Rev. 2.0, 08/02, page 314 of 788

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

13.4.4

2fH Modification of IHI Signal

By using the timer connection facility and 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 TCR, TCSR, TOCR, and OCRDM settings in the FRT are shown in table 13.7, and

the 2fH modification timing chart is shown in figure 13.6.

HD64F2145 Datasheet(PDF) 354 Page - Renesas Technology Corp