PIC18F87J10 Datasheet, PDF (181/394 Pages) Microchip Technology – 64/80-Pin High-Performance, 1-Mbit Flash Microcontrollers with nanoWatt Technology

PIC18F87J10 FAMILY
REGISTER 17-3:
ECCPxAS: ENHANCED CCP 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
ECCPxASE ECCPxAS2 ECCPxAS1 ECCPxAS0 PSSxAC1 PSSxAC0 PSSxBD1 PSSxBD0
bit 7
bit 0
bit 7
bit 6-4
bit 3-2
bit 1-0
ECCPxASE: ECCP Auto-Shutdown Event Status bit
0 = ECCP outputs are operating
1 = A shutdown event has occurred; ECCP outputs are in shutdown state
ECCPxAS2:ECCPxAS0: ECCP Auto-Shutdown Source Select bits
000 = Auto-shutdown is disabled
001 = Comparator 1 output
010 = Comparator 2 output
011 = Either Comparator 1 or 2
100 = INT0
101 = INT0 or Comparator 1
110 = INT0 or Comparator 2
111 = INT0 or Comparator 1 or Comparator 2
PSSxAC1:PSSxAC0: Pins A and C Shutdown State Control bits
00 = Drive Pins A and C to ‘0’
01 = Drive Pins A and C to ‘1’
1x = Pins A and C tri-state
PSSxBD1:PSSxBD0: Pins B and D Shutdown State Control bits
00 = Drive Pins B and D to ‘0’
01 = Drive Pins B and D to ‘1’
1x = Pins B and D tri-state
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
17.4.7.1 Auto-Shutdown and Automatic
Restart
The auto-shutdown feature can be configured to allow
automatic restarts of the module following a shutdown
event. This is enabled by setting the P1RSEN bit of the
ECCP1DEL register (ECCP1DEL<7>).
In Shutdown mode with P1RSEN = 1 (Figure 17-10),
the ECCPASE bit will remain set for as long as the
cause of the shutdown continues. When the shutdown
condition clears, the ECCP1ASE bit is cleared. If
P1RSEN = 0 (Figure 17-11), once a shutdown condi-
tion occurs, the ECCP1ASE bit will remain set until it is
cleared by firmware. Once ECCP1ASE is cleared, the
Enhanced PWM will resume at the beginning of the
next PWM period.
Note: Writing to the ECCPASE bit is disabled
while a shutdown condition is active.
Independent of the P1RSEN bit setting, if the
auto-shutdown source is one of the comparators, the
shutdown condition is a level. The ECCP1ASE bit
cannot be cleared as long as the cause of the shutdown
persists.
The Auto-Shutdown mode can be forced by writing a ‘1’
to the ECCPASE bit.
17.4.8 START-UP CONSIDERATIONS
When the ECCP module is used in the PWM mode, the
application hardware must use the proper external
pull-up and/or pull-down resistors on the PWM output
pins. When the microcontroller is released from Reset,
all of the I/O pins are in the high-impedance state. The
external circuits must keep the power switch devices in
the OFF state until the microcontroller drives the I/O
pins with the proper signal levels, or activates the PWM
output(s).
The CCP1M1:CCP1M0 bits (CCP1CON<1:0>) allow
the user to choose whether the PWM output signals are
active-high or active-low for each pair of PWM output
pins (P1A/P1C and P1B/P1D). The PWM output
polarities must be selected before the PWM pins are
configured as outputs. Changing the polarity configura-
tion while the PWM pins are configured as outputs is
not recommended since it may result in damage to the
application circuits.
 2005 Microchip Technology Inc.
Advance Information
DS39663A-page 179