EFM32WG Datasheet, PDF (527/834 Pages) List of Unclassifed Manufacturers – The EFM32WG Wonder Gecko is the ideal choice for demanding 8-, 16-, and 32-bit energy sensitive applications.

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on compare match, overflow and underflow through the CMOA, COFOA and CUFOA fields in
TIMERn_CCx_CTRL. TIMERn_CCx_CCV can be accessed directly or through the buffer register
TIMERn_CCx_CCVB, see Figure 20.12 (p. 527) . When writing to the buffer register, the value in
TIMERn_CCx_CCVB will be written to TIMERn_CCx_CCV on the next update event. This functionality
ensures glitch free PWM outputs. The CCVBV flag in TIMERn_STATUS indicates whether the
TIMERn_CCx_CCVB register contains data that have not yet been written to the TIMERn_CCx_CCV
register. Note that when writing 0 to TIMERn_CCx_CCVB the CCV value is updated when the timer
counts from 0 to 1. Thus, the compare match for the next period will not happen until the timer reaches
0 again on the way down.
Figure 20.12. TIMER Output Compare/PWM Buffer Functionality
APB Writ e (CCB)
Updat e event
Load APBCCV B
Set
Clear
CCV BV
APB Writ e (CC)
Load CCB
Load APB
CCV
20.3.2.3 Input Capture
In Input Capture Mode, the counter value (TIMERn_CNT) can be captured in the Compare/Capture
Register (TIMERn_CCx_CCV), see Figure 20.13 (p. 527) . In this mode, TIMERn_CCx_CCV
is read-only. Together with the Compare/Capture Buffer Register (TIMERn_CCx_CCVB) the
TIMERn_CCx_CCV form a double-buffered capture registers allowing two subsequent capture events
to take place before a read-out is required. The CCPOL bits in TIMERn_STATUS indicate the polarity
the edge that triggered the capture in TIMERn_CCx_CCV.
Figure 20.13. TIMER Input Capture
Input
z
y
n
TIMERn_CNT ^m
TIMERn _CCx _CCV
prev. val
m
TIMERn_CCx_CCVB prev. val
m
y
Read TIMERn_CCx_CCVB
20.3.2.3.1 Period/Pulse-Width Capture
Period and/or pulse-width capture can be achieved by setting the RISEA field in TIMERn_CTRL to
Clear&Start, and select the wanted input from either external pin or PRS, see Figure 20.14 (p. 528) .
For period capture, the Compare/Capture Channel should then be set to input capture on a rising edge
of the same input signal. To capture a the width of a high pulse, the Compare/Capture Channel should
be set to capture on a falling edge of the input signal. To start the measuring period on either a falling
edge or measure the low pulse-width of a signal, opposite polarities should be chosen.
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
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