Datasheet

 2010-2012 Microchip Technology Inc. DS39977F-page 279
PIC18F66K80 FAMILY
A shutdown condition is indicated by the ECCP1ASE
(Auto-Shutdown Event Status) bit (ECCP1AS<7>). If
the bit is a ‘
0’, the PWM pins are operating normally. If
the bit is a ‘
1’, the PWM outputs are in the shutdown
state.
When a shutdown event occurs, two things happen:
• The ECCP1ASE bit is set to ‘
1’. The ECCP1ASE
will remain set until cleared in firmware or an
auto-restart occurs. (See
Section 20.4.5
“Auto-Restart Mode”
.)
• The enabled PWM pins are asynchronously
placed in their shutdown states. The PWM output
pins are grouped into pairs (P1A/P1C) and
(P1B/P1D). The state of each pin pair is
determined by the PSS1ACx and PSS1BDx bits
(ECCP1AS<3:2> and <1:0>, respectively).
Each pin pair may be placed into one of three states:
• Drive logic ‘
1’
• Drive logic ‘
0’
• Tri-state (high-impedance)
REGISTER 20-3: ECCP1AS: ECCP1 AUTO-SHUTDOWN CONTROL REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
ECCP1ASE ECCP1AS2 ECCP1AS1 ECCP1AS0 PSS1AC1 PSS1AC0 PSS1BD1 PSS1BD0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7
ECCP1ASE: ECCP Auto-Shutdown Event Status bit
1 = A shutdown event has occurred; ECCP outputs are in a shutdown state
0 = ECCP outputs are operating
bit 6-4
ECCP1AS<2:0>: ECCP Auto-Shutdown Source Select bits
000 = Auto-shutdown is disabled
001 = Comparator C1OUT output is high
010 = Comparator C2OUT output is high
011 = Either Comparator C1OUT or C2OUT is high
100 =VIL on FLT0 pin
101 =VIL on FLT0 pin or Comparator C1OUT output is high
110 =VIL on FLT0 pin or Comparator C2OUT output is high
111 =VIL on FLT0 pin or Comparator C1OUT or Comparator C2OUT is high
bit 3-2
PSS1AC<1:0>: P1A and P1C Pins Shutdown State Control bits
00 = Drive pins, P1A and P1C, to ‘0’
01 = Drive pins, P1A and P1C, to ‘1’
1x = Pins, P1A and P1C, tri-state
bit 1-0
PSS1BD<1:0>: P1B and P1D Pins Shutdown State Control bits
00 = Drive pins, P1B and P1D, to ‘0’
01 = Drive pins, P1B and P1D, to ‘1’
1x = Pins, P1B and P1D, tri-state
Note 1: The auto-shutdown condition is a level-based signal, not an edge-based signal. As long as the level is
present, the auto-shutdown will persist.
2: Writing to the ECCP1ASE bit is disabled while an auto-shutdown condition persists.
3: Once the auto-shutdown condition has been removed and the PWM restarted (either through firmware or
auto-restart), the PWM signal will always restart at the beginning of the next PWM period.