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Reaction Module (REACM)
ON
timer
control
signal
OFF
i
a
In some applications the modulation runs continuously and the input timer
control signal is not used as a modulation pulse control but only as an
enabling signal. Therefore, if the modulation is turned off, the REACM can
issue a Modulation Word Sequence Error by setting SQER flag. In this case,
this SQER flag can be ignored (masked) without prejudice.
An option, if the application permits, is to disable the REACM channel
(CHEN = 00), thus avoiding unwanted SQER error.
23.5.3.3
CHOFF behavior during modulation
The CHOFF—channel output disable bit
before a modulation cycle had ended. This is important on error conditions detected by the software, thus
setting the channel outputs to a safe state defined by DOFF. It is important to notice that in order to
reactivate the channel by setting CHOFF = 0 does not implies that the channel outputs immediately returns
to the state defined by HOD and LOD on the modulation word being executed. Instead, the HOD and LOD
are driven to the channel outputs only when one of the following conditions occur:
•
a sequence advance event (timeout or threshold, depending on SM).
•
a new sample is received (no matter if the comparison matches or not).
•
a hold-off timeout.
730
OFF
early end of pulse
Modulation word 2 is partially executed
Modulation words 3 and 4
are not executed
DOFF
b
c
d
e
Figure 23-30. Early end of Timer Control pulse
NOTE
(Figure
MPC5644A Microcontroller Reference Manual, Rev. 6
a
b
c
23-9) is intended to disable the channel immediately
time
time
d
e
Freescale Semiconductor
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