PIC16F883 Microchip Technology Inc., PIC16F883 Datasheet - Page 143

• Manufacturer Part Number: PIC16F883
• Description: 28/40/44-pin Flash-based, 8-bit Cmos Microcontrollers With Nanowatt Technology
• Manufacturer: Microchip Technology Inc.

11.6.4
The PWM mode supports an Auto-Shutdown mode that
will disable the PWM outputs when an external
shutdown event occurs. Auto-Shutdown mode places
the PWM output pins into a predetermined state. This
mode is used to help prevent the PWM from damaging
the application.
The auto-shutdown sources are selected using the
ECCPAS<2:0> bits of the ECCPAS register. A shutdown
event may be generated by:
• A logic ‘0’ on the INT pin
• Comparator C1
• Comparator C2
• Setting the ECCPASE bit in firmware
REGISTER 11-3:
© 2007 Microchip Technology Inc.
bit 7
Legend:
R = Readable bit
-n = Value at POR
bit 7
bit 6-4
bit 3-2
bit 1-0
Note 1:
ECCPASE
R/W-0
If C2SYNC is enabled, the shutdown will be delayed by Timer1.
ENHANCED PWM
AUTO-SHUTDOWN MODE
ECCPASE: ECCP Auto-Shutdown Event Status bit
1 = A shutdown event has occurred; ECCP outputs are in shutdown state
0 = ECCP outputs are operating
ECCPAS<2:0>: ECCP Auto-shutdown Source Select bits
000 = Auto-Shutdown is disabled
001 = Comparator C1 output change
010 = Comparator C2 output change
011 = Either Comparator C1 or C2 change
100 = V
101 = V
110 = V
111 = V
PSSACn: Pins P1A and P1C 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
PSSBDn: Pins P1B and P1D 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
ECCPAS2
R/W-0
ECCPAS: ENHANCED CAPTURE/COMPARE/PWM AUTO-SHUTDOWN
CONTROL REGISTER
IL
IL
IL
IL
on INT pin
on INT pin or Comparator C1 change
on INT pin or Comparator C2 change
on INT pin or Comparator C1 or Comparator C2 change
W = Writable bit
‘1’ = Bit is set
ECCPAS1
R/W-0
PIC16F882/883/884/886/887
ECCPAS0
R/W-0
Preliminary
(1)
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
PSSAC1
R/W-0
A shutdown condition is indicated by the ECCPASE
(Auto-Shutdown Event Status) bit of the ECCPAS
register. 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 ECCPASE bit is set to ‘1’. The ECCPASE will
remain set until cleared in firmware or an auto-restart
occurs (see Section 11.6.5 “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 PSSAC and
PSSBD bits of the ECCPAS register. Each pin pair may
be placed into one of three states:
• Drive logic ‘1’
• Drive logic ‘0’
• Tri-state (high-impedance)
PSSAC0
R/W-0
x = Bit is unknown
PSSBD1
R/W-0
DS41291D-page 141
PSSBD0
R/W-0
bit 0