DSPIC30F4012 Microchip Technology Inc., DSPIC30F4012 Datasheet - Page 101

• Manufacturer Part Number: DSPIC30F4012
• Description: Dspic30f4011/4012 Enhanced Flash 16-bit Digital Signal Controller
• Manufacturer: Microchip Technology Inc.

15.11 PWM Output and Polarity Control
There are three device Configuration bits associated
with the PWM module that provide PWM output pin
control:
• HPOL Configuration bit
• LPOL Configuration bit
• PWMPIN Configuration bit
These three bits in the FPORBOR Configuration regis-
ter (see Section 21.0 “System Integration”) work in
conjunction with the six PWM Enable bits (PENxL and
PENxH). The Configuration bits and PWM Enable bits
ensure that the PWM pins are in the correct states after
a device Reset occurs. The PWMPIN Configuration
fuse allows the PWM module outputs to be optionally
enabled on a device Reset. If PWMPIN = 0, the PWM
outputs will be driven to their inactive states at Reset. If
PWMPIN = 1 (default), the PWM outputs will be tri-
stated. The HPOL bit specifies the polarity for the
PWMxH outputs, whereas the LPOL bit specifies the
polarity for the PWMxL outputs.
15.11.1
The PEN<3:1>H and PEN<3:1>L control bits in the
PWMCON1 SFR enable each high PWM output pin
and each low PWM output pin, respectively. If a partic-
ular PWM output pin is not enabled, it is treated as a
general purpose I/O pin.
15.12 PWM Fault Pin
There is one Fault pin (FLTA) associated with the PWM
module. When asserted, these pins can optionally drive
each of the PWM I/O pins to a defined state.
15.12.1
The FLTACON SFR has 3 control bits that determine
whether a particular pair of PWM I/O pins is to be
controlled by the Fault input pin. To enable a
specific PWM I/O pin pair for Fault overrides, the
corresponding bit should be set in the FLTACON
register.
If all enable bits are cleared in the FLTACON register,
then the corresponding Fault input pin has no effect on
the PWM module and the pin may be used as a general
purpose interrupt or I/O pin.
© 2007 Microchip Technology Inc.
Note:
FAULT PIN ENABLE BITS
OUTPUT PIN CONTROL
The Fault pin logic can operate indepen-
dent of the PWM logic. If all the enable bits
in the FLTACON register are cleared, then
the Fault pin could be used as a general
purpose interrupt pin. The Fault pin has an
interrupt vector, interrupt flag bit and
interrupt priority bits associated with it.
15.12.2
The FLTACON Special Function Register has 6 bits
that determine the state of each PWM I/O pin when it is
overridden by a Fault input. When these bits are
cleared, the PWM I/O pin is driven to the inactive state.
If the bit is set, the PWM I/O pin will be driven to the
active state. The active and inactive states are refer-
enced to the polarity defined for each PWM I/O pin
(HPOL and LPOL polarity control bits).
A special case exists when a PWM module I/O pair is
in the Complementary mode and both pins are
programmed to be active on a Fault condition. The
PWMxH pin always has priority in the Complementary
mode, so that both I/O pins cannot be driven active
simultaneously.
15.12.3
The Fault input pin has two modes of operation:
• Latched Mode: When the Fault pin is driven low,
• Cycle-by-Cycle Mode: When the Fault input pin
The operating mode for the Fault input pin is selected
using the FLTAM control bit in the FLTACON Special
Function Register.
The Fault pin can be controlled manually in software.
the PWM outputs will go to the states defined in
the FLTACON register. The PWM outputs will
remain in this state until the Fault pin is driven
high and the corresponding interrupt flag has
been cleared in software. When both of these
actions have occurred, the PWM outputs will
return to normal operation at the beginning of the
next PWM cycle or half-cycle boundary. If the
interrupt flag is cleared before the Fault condition
ends, the PWM module will wait until the Fault pin
is no longer asserted to restore the outputs.
is driven low, the PWM outputs remain in the
defined Fault states for as long as the Fault pin is
held low. After the Fault pin is driven high, the
PWM outputs return to normal operation at the
beginning of the following PWM cycle or
half-cycle boundary.
dsPIC30F4011/4012
FAULT STATES
FAULT INPUT MODES
DS70135E-page 99