NEC 78K0 User Manual page 146

Figure 6-23. Timing of Pulse Width Measurement Operation with Free-Running Counter
t
Count clock
TM00 count value 0000H
TI000 pin input
CR010 capture value
CR000 capture value
INTTM010
OVF00
Note Clear OVF00 by software.
(4) Pulse width measurement by means of restart
When input of a valid edge to 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 operation.
Either of two edgesrising or fallingcan be selected using bits 4 and 5 (ES000 and ES001) of prescaler mode
register 00 (PRM00).
Sampling is performed using the count clock cycle 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.
146
CHAPTER 6 16-BIT TIMER/EVENT COUNTER 00
and Two Capture Registers (with Rising Edge Specified)
0001H D0 D0 + 1
D0
(D1 − D0) × t
User's Manual U16227EJ2V0UD
D1 D1 + 1 FFFFH 0000H
D1
(10000H − D1 + D2) × t
D2 D2 + 1 D3
D2
D3
Note
(D3 − D2) × t