PIC16(L)F1508/9
DS40001609E-page 284
2011-2015 Microchip Technology Inc.
26.8
Dead-Band Uncertainty
When the rising and falling edges of the input source
triggers the dead-band counters, the input may be asyn-
chronous. This will create some uncertainty in the dead-
band time delay. The maximum uncertainty is equal to
one CWG clock period. Refer to
for more
detail.
EQUATION 26-1:
DEAD-BAND
UNCERTAINTY
26.9
Auto-Shutdown Control
Auto-shutdown is a method to immediately override the
CWG output levels with specific overrides that allow for
safe shutdown of the circuit. The shutdown state can be
either cleared automatically or held until cleared by
software.
26.9.1
SHUTDOWN
The shutdown state can be entered by either of the
following two methods:
• Software generated
• External Input
26.9.1.1
Software Generated Shutdown
Setting the GxASE bit of the CWGxCON2 register will
force the CWG into the shutdown state.
When auto-restart is disabled, the shutdown state will
persist as long as the GxASE bit is set.
When auto-restart is enabled, the GxASE bit will clear
automatically and resume operation on the next rising
edge event. See
.
26.9.1.2
External Input Source
External shutdown inputs provide the fastest way to
safely suspend CWG operation in the event of a Fault
condition. When any of the selected shutdown inputs
goes active, the CWG outputs will immediately go to
the selected override levels without software delay. Any
combination of two input sources can be selected to
cause a shutdown condition. The sources are:
• Comparator C1 – C1OUT_async
• Comparator C2 – C2OUT_async
• CLC2 – LC2_out
• CWG1FLT
Shutdown inputs are selected in the CWGxCON2
register. (
T
DEADBAND
_
UNCERTAINTY
1
Fcwg_clock
-----------------------------
=
Therefore:
Fcwg_clock
16 MHz
=
1
16 MHz
-------------------
=
62.5ns
=
T
DEADBAND
_
UNCERTAINTY
1
Fcwg_clock
-----------------------------
=
Example:
Note:
Shutdown inputs are level sensitive, not
edge sensitive. The shutdown state can-
not be cleared, except by disabling auto-
shutdown, as long as the shutdown input
level persists.
