Datasheet

48.6.2.8.2 Period and Pulse-Width (PPW) Capture Action
The TC can perform two input captures and restart the counter on one of the edges. This enables the TC
to measure the pulse width and period and to characterize the frequency f and duty cycle of an input
signal:
 =
1

dutyCycle =



Figure 48-13. PWP Capture
Period (T)
external signal
events
COUNT
MAX
ZERO
"capture"
Pulsewitdh (t
p
)
CC0 CC0 CC1CC1
Selecting PWP in the Event Action bit group in the Event Control register (EVCTRL.EVACT) enables the
TC to perform one capture action on the rising edge and the other one on the falling edge. The period T
will be captured into CC1 and the pulse width t
p
in CC0. EVCTRL.EVACT=PPW (period and pulse-width)
offers identical functionality, but will capture T into CC0 and t
p
into CC1.
The TC Event Input Invert Enable bit in the Event Control register (EVCTRL.TCINV) is used to select
whether the wraparound should occur on the rising edge or the falling edge. If EVCTRL.TCINV=1, the
wraparound will happen on the falling edge. In case pin capture is enabled, this can also be achieved by
modifying the value of the DRVCTRL.INVENx bit.
The TC can detect capture overflow of the input capture channels: When a new capture event is detected
while the Capture Interrupt flag (INTFLAG.MCx) is still set, the new timestamp will not be stored and
INTFLAG.ERR will be set.
Note: The corresponding capture is working only if the channel is enabled in capture mode
(CTRLA.CAPTENx=1). If not, the capture action is ignored and the channel is enabled in compare mode
of operation. Consequently, both channels must be enabled in order to fully characterize the input.
48.6.2.8.3 Pulse-Width Capture Action
The TC performs the input capture on the falling edge of the input signal. When the edge is detected, the
counter value is cleared and the TC stops counting. When a rising edge is detected on the input signal,
the counter restarts the counting operation. To enable the operation on opposite edges, the input signal to
capture must be inverted (refer to DRVCTRL.INVEN or EVCTRL.TCEINV).
SAM D5x/E5x Family Data Sheet
TC – Timer/Counter
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 1724