
2011 Microchip Technology Inc.
Preliminary
DS41579B-page 203
PIC16(L)F1782/3
24.2.8
INPUT BLANKING
Input blanking is a function whereby the inputs from
any selected asynchronous input may be driven inac-
tive for a short period of time. This is to prevent electri-
cal
transients
from
the
turn-on/off
of
power
components from generating a false event.
Rising edge and falling edge blanking are controlled
independently. The following features are available for
blanking:
Blanking mode
Blanking time counters
Blanking enable
There is no blanking available for a period event.
The following Blanking modes are available:
Blanking disabled
Immediate blanking
The Falling Edge Blanking mode is set with the
PxFEBM<1:0> bits of the PSMCx Blanking Control
The Rising Edge Blanking mode is set with the
PxREBM<1:0> bits of the PSMCx Blanking Control
24.2.8.1
Blanking Disabled
With blanking disabled, the asynchronous inputs are
passed to PSMC module without any intervention.
24.2.8.2
Immediate Blanking
With Immediate blanking, a counter is used to deter-
mine the blanking period. The desired blanking time is
measured in psmc_clk periods. A rising edge event
will start incrementing the rising edge blanking coun-
ter. A falling edge event will start incrementing the fall-
ing edge blanking counter.
The rising edge blanking time is set with the PSMC
Rising Edge Blanking Time (PSMCxBLKR) register
selected with the PSMC Rising Edge Blanked Source
edge blanking, the selected blanked sources are sup-
pressed for falling edge as well as rising edge,
auto-shutdown and period events.
The falling edge blanking time is set with the PSMC
Falling Edge Blanking Time (PSMCxBLKF) register
selected with the PSMC Falling Edge Blanked Source
ing edge blanking, the selected blanked sources are
suppressed for rising edge, as well as falling edge,
auto-shutdown, and period events.
The blanking counters are incremented on the rising
edge of psmc_clk. Blanked sources are suppressed
until the counter value equals the blanking time regis-
ter causing the blanking to terminate.
As the rising and falling edge events are from asyn-
chronous inputs, there may be some uncertainty in the
actual blanking time implemented in each cycle. The
maximum uncertainty is equal to one psmc_clk period.
24.2.9
OUTPUT WAVEFORM
GENERATION
The PSMC PWM output waveform is generated based
upon the different input events. However, there are
several other factors that affect the PWM waveshapes:
Output Control
- Output Enable
- Output Polarity
Waveform Mode Selection
Dead-band Control
Steering control
24.2.10
OUTPUT CONTROL
24.2.10.1
Output Pin Enable
Each PSMC PWM output pin has individual output
enable control.
When the PSMC output enable control is disabled, the
module asserts no control over the pin. In this state,
the pin can be used for general purpose I/O or other
associate peripheral use.
When the PSMC output enable is enabled, the active
PWM waveform is applied to the pin per the port prior-
ity selection.
PSMC output enable selections are made with the
PSMC Output Enable Control (PSMCxOEN) register
24.2.10.2
Output Steering
PWM output will be presented only on pins for which
output steering is enabled. The PSMC has up to 6
PWM outputs. The PWM signal in some modes can be
steered to one or more of these outputs.
Steering differs from output enable in the following
manner: When the output is enabled but the PWM
steering to the corresponding output is not enabled,
then general purpose output to the pin is disabled and
the pin level will remain constantly in the inactive PWM
state. Output steering is controlled with the PSMCS
Steering
Control
0
(PSMCxSTR0)
register
Steering operates only in the following modes:
Single-phase
Complementary Single-phase
3-phase 6-step PWM
24.2.10.3
Polarity Control
Each PSMC output has individual output polarity con-
trol. Polarity is set with the PSMC Polarity Control