CHAPTER 6 16-BIT TIMER/EVENT COUNTER 00
Preliminary User’s Manual U16846EJ1V0UD
127
Figure 6-23. Timing of Pulse Width Measurement Operation with Free-Running Counter
and Two Capture Registers (with Rising Edge Specified)
t
0000H
0000H
FFFFH
0001H
D0
D0
INTTM010
OVF00
D2
D1
D3
D2
D3
D0 + 1
D2 + 1
D1
D1 + 1
CR000 capture value
Count clock
TM00 count value
TI000 pin input
CR010 capture value
(D1 – D0)
×
t
(D3 – D2)
×
t
(10000H – D1 + D2)
×
t
Note
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 the valid level of the TI000 pin is detected twice, thus eliminating noise
with a short pulse width.