UPD78F9234MC-5A4-A Datasheet, PDF (112/419 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 6 16-BIT TIMER/EVENT COUNTER 00
Figure 6-24. Timing of Pulse Width Measurement Operation by Free-Running Counter
and Two Capture Registers (with Rising Edge Specified)
t
Count clock
TM00 count value
TI000 pin input
CR010 capture value
CR000 capture value
INTTM010
0000H 0001H
D0 D0 + 1
D0
D1 D1 + 1
FFFFH 0000H
D1
D2 D2 + 1
D2
D3
D3
(D1 − D0) × t
(D2 − D1) × t ^Note
(D3 − D2) × t
Note The carry flag is set to 1. Ignore this setting.
(4) Pulse width measurement by means of restart
Specify both the rising and falling edges as the valid edges of the TI000 pin, by using bits 4 and 5 (ES000 and
ES010) of PRM00.
When a valid edge of the TI000 pin is detected, the count value of 16-bit timer/counter 00 (TM00) is taken into
16-bit timer capture/compare register 010 (CR010), and then the pulse width of the signal input to the TI000
pin is measured by clearing TM00 and restarting the count.
Sampling is performed at the interval selected by prescaler mode register 00 (PRM00) and a capture operation
is only performed when a valid level of the TI000 pin is detected twice, thus eliminating noise with a short
pulse width.
Caution The measurable pulse width in this operation example is up to 1 cycle of the timer counter.
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User’s Manual U17446EJ5V0UD