Information

37.4.15 Output Mask
The output mask can be used to force channels output to their inactive state through
software (for example: to control a BLDC motor).
Any write to the OUTMASK register updates its write buffer. The OUTMASK register is
updated with its buffer value by PWM synchronization (OUTMASK Register
Synchronization).
If CHnOM = 1, then the channel (n) output is forced to its inactive state (POLn bit value).
If CHnOM = 0, then the channel (n) output is unaffected by the output mask (see the
following figure).
FTM counter
channel (n) output
(before output mask)
CHnOM bit
channel (n) output
(after output mask)
the beginning of new PWM cycles
configured PWM signal starts
to be available in the channel (n) output
channel (n) output is disabled
Figure 37-232. Output Mask with POLn = 0
The following table shows the output mask result before the polarity control.
Table 37-244. Output Mask Result for Channel (n) (Before the Polarity
Control)
CHnOM Output Mask Input Output Mask Result
0 inactive state inactive state
active state active state
1 inactive state inactive state
active state
Chapter 37 FlexTimer (FTM)
K20 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc. 951