PIC16F753 Datasheet, PDF (95/238 Pages) Microchip Technology – 14/16-Pin, Flash-Based 8-Bit CMOS Microcontrollers

11.5.4 RISING EVENT DEAD BAND
Rising event dead band adds a delay between the
COGxOUT1 signal deactivation and the COGxOUT0
signal activation. The rising event dead-band time
starts when the rising_event output goes true.
See Section 11.5.1, Asynchronous Delay Chain
Dead-band Delay and Section 11.5.2, Synchronous
Counter Dead-band Delay for more information on
setting the rising edge dead-band time.
11.5.5 FALLING EVENT DEAD BAND
Falling event dead band adds a delay between the
COGxOUT1 signal deactivation and the COGxOUT0
signal activation. The falling event dead-band time
starts when the falling_event output goes true.
See Section 11.5.1, Asynchronous Delay Chain
Dead-band Delay and Section 11.5.2, Synchronous
Counter Dead-band Delay for more information on
setting the rising edge dead-band time.
11.5.6 DEAD-BAND OVERLAP
There are two cases of dead-band overlap:
• Rising-to-falling
• Falling-to-rising
11.5.6.1 Rising-to-Falling Overlap
In this case, the falling event occurs while the rising
event dead-band counter is still counting. When this
happens, the COGxOUT0 drive is suppressed and the
dead band extends by the falling event dead-band
time. At the termination of the extended dead-band
time, the COGxOUT1 drive goes true.
11.5.6.2 Falling-to-Rising Overlap
In this case, the rising event occurs while the falling
event dead-band counter is still counting. When this
happens, the COGxOUT1 drive is suppressed and the
dead band extends by the rising event dead-band
time. At the termination of the extended dead-band
time, the COGxOUT0 drive goes true.
11.6 Blanking Control
Input blanking is a function, whereby the event inputs
can be masked or blanked for a short period of time.
This is to prevent electrical transients caused by the
turn-on/off of power components from generating a
false input event.
The COG contains two blanking counters: one
triggered by the rising event and the other triggered by
the falling event. The counters are cross-coupled with
the events they are blanking. The falling event
blanking counter is used to blank rising input events
and the rising event blanking counter is used to blank
PIC16F753/HV753
falling input events. Once started, blanking extends for
the time specified by the corresponding blanking
counter.
Blanking is timed by counting COG_clock periods from
zero up to the value in the blanking count register. Use
Equation 11-1 to calculate blanking times.
11.6.1
FALLING EVENT BLANKING OF
RISING EVENT INPUTS
The falling event blanking counter inhibits rising event
inputs from triggering a rising event. The falling event
blanking time starts when the rising event output drive
goes false.
The falling event blanking time is set by the value
contained in the COGxBLKF register (Register 11-12).
Blanking times are calculated using the formula shown
in Equation 11-1.
When the COGxBLKF value is zero, the falling event
blanking is disabled and the blanking counter output is
true, thereby allowing the event signal to pass straight
through to the event trigger circuit.
11.6.2
RISING EVENT BLANKING OF
FALLING EVENT INPUTS
The rising event blanking counter inhibits falling event
inputs from triggering a falling event. The rising event
blanking time starts when the falling event output drive
goes false.
The rising event blanking time is set by the value
contained in the COGxBLKR register (Register 11-11).
When the COGxBLKR value is zero, the rising event
blanking is disabled and the blanking counter output is
true, thereby allowing the event signal to pass straight
through to the event trigger circuit.
11.6.3 BLANKING TIME UNCERTAINTY
When the rising and falling sources that trigger the
blanking counters are asynchronous to the
COG_clock, it creates uncertainty in the blanking time.
The maximum uncertainty is equal to one COG_clock
period. Refer to Equation 11-1 and Example 11-2 for
more detail.
11.7 Phase Delay
It is possible to delay the assertion of either or both the
rising event and falling event. This is accomplished by
placing a non-zero value in COGxPHR or COGxPHF
phase delay count register, respectively
(Register 11-13 and Register 11-14). Refer to
Figure 11-5 for COG operation with CCP1 and phase
delay. The delay from the input rising event signal
switching to the actual assertion of the events is
calculated the same as the dead-band and blanking
delays. Please see Equation 11-1.
 2013 Microchip Technology Inc.
Preliminary
DS40001709A-page 95