NEC 78K0S/KA1+ User Manual page 104

Figure 6-24. Timing of Pulse Width Measurement Operation by Free-Running Counter
t
Count clock
TM00 count value 0000H
TI000 pin input
CR010 capture value
CR000 capture value
INTTM010
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.
Figure 6-25. Control Register Settings for Pulse Width Measurement by Means of Restart
7 6
CRC00 0 0
104
CHAPTER 6 16-BIT TIMER/EVENT COUNTER 00
and Two Capture Registers (with Rising Edge Specified)
0001H D0 D0 + 1
D0
(D1 − D0) × t
(with Rising Edge Specified) (1/2)
(a) Capture/compare control register 00 (CRC00)
5 4 3 CRC002 CRC001
0 0 0 1 1
User's Manual U16898EJ3V0UD
D1 D1 + 1 FFFFH 0000H
D1
(D2 − D1) × t Note
CRC000
1
CR000 used as capture register
Captures to CR000 at inverse edge to valid edge of TI000
CR010 used as capture register
D2 D2 + 1 D3
D2
D3
(D3 − D2) × t
Note
.