Datasheet

 2013-2015 Microchip Technology Inc. DS40001723D-page 235
PIC12(L)F1571/2
23.8 Dead-Band Uncertainty
When the rising and falling edges of the input source
triggers the dead-band counters, the input may be
asynchronous. This will create some uncertainty in the
dead-band time delay. The maximum uncertainty is
equal to one CWG clock period. Refer to Equation 23-1
for more detail.
EQUATION 23-1: DEAD-BAND
UNCERTAINTY
23.9 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.
23.9.1 SHUTDOWN
The shutdown state can be entered by either of the
following two methods:
• Software generated
• External Input
23.9.1.1 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 Figure 23-6.
23.9.1.2 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
•
CWG1FLT
Shutdown inputs are selected in the CWGxCON2
register (Register 23-3).
TDEADBAND_UNCERTAINTY
1
Fcwg_clock
-----------------------------=
Therefore:
Fcwg_clock 16 MHz=
1
16 MHz
-------------------=
62.5ns=
TDEADBAND_UNCERTAINTY
1
Fcwg_clock
-----------------------------=
Example:
Note: Shutdown inputs are level sensitive, not
edge sensitive. The shutdown state
cannot be cleared, except by disabling
auto-shutdown, as long as the shutdown
input level persists.