NEC 78K0 User Manual page 143

(2) Measurement of two pulse widths with free-running counter
When 16-bit timer counter 00 (TM00) is operated in free-running mode, it is possible to simultaneously measure
the pulse widths of the two signals input to the TI000 pin and the TI010 pin.
When the edge specified by bits 4 and 5 (ES000 and ES001) of prescaler mode register 00 (PRM00) is input to
the TI000 pin, the value of TM00 is taken into 16-bit timer capture/compare register 010 (CR010) and an interrupt
request signal (INTTM010) is set.
Also, when the edge specified by bits 6 and 7 (ES100 and ES101) of PRM00 is input to the TI010 pin, the value
of TM00 is taken into 16-bit timer capture/compare register 000 (CR000) and an interrupt request signal
(INTTM000) is set.
Specify both the rising and falling edges as the edges of the TI000 and TI010 pins, by using bits 4 and 5 (ES000
and ES001) and bits 6 and 7 (ES100 and ES101) of 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 or TI010 pin is detected twice, thus
eliminating noise with a short pulse width.
Figure 6-20. Control Register Settings for Measurement of Two Pulse Widths with Free-Running Counter
7 6
TMC00 0 0
7 6
CRC00 0 0
ES101 ES100 ES001
PRM00 1 1
Remark 0/1: Setting 0 or 1 allows another function to be used simultaneously with pulse width measurement.
See the description of the respective control registers for details.
CHAPTER 6 16-BIT TIMER/EVENT COUNTER 00
(a) 16-bit timer mode control register 00 (TMC00)
5 4 TMC003 TMC002 TMC001
0 0 0 1 0/1
(b) Capture/compare control register 00 (CRC00)
5 4 3 CRC002 CRC001
0 0 0 1 0
(c) Prescaler mode register 00 (PRM00)
ES000 3 2 PRM001
1 1 0 0 0/1
User's Manual U16227EJ2V0UD
OVF00
0
Free-running mode
CRC000
1
CR000 used as capture register
Captures valid edge of TI010 pin to CR000.
CR010 used as capture register
PRM000
0/1
Selects count clock (setting "11" is prohibited).
Specifies both edges for pulse width detection.
Specifies both edges for pulse width detection.
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