PIC16LF1508 Datasheet, PDF (304/384 Pages) Microchip Technology – 20-Pin Flash, 8-Bit Microcontrollers with nanoWatt XLP Technology

PIC16(L)F1508/9
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 fol-
lowing 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 Figure 26-6.
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:
• async_C1OUT
• async_C2OUT
• LC2OUT
• CWG1FLT
Shutdown inputs are selected using the GxASDS0 and
GxASDS1 bits of the CWGxCON2 register.
(Register 26-3).
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.
26.10 Operation During Sleep
The CWG module operates independently from the
system clock and will continue to run during Sleep,
provided that the clock and input sources selected
remain active.
The HFINTOSC remains active during Sleep, provided
that the CWG module is enabled, the input source is
active, and the HFINTOSC is selected as the clock
source, regardless of the system clock source
selected.
In other words, if the HFINTOSC is simultaneously
selected as the system clock and the CWG clock
source, when the CWG is enabled and the input
source is active, the CPU will go idle during Sleep, but
the CWG will continue to operate and the HFINTOSC
will remain active.
This will have a direct effect on the Sleep mode current.
DS41609A-page 304
Preliminary
 2011 Microchip Technology Inc.