Power Application Controller
®
-64-
Copyright 2020 © Qorvo, Inc.
Rev 1.2
– Jan 17, 2019
The blanking time for the comparator may be configured to use leading edge, trailing edge, leading/trailing
edge or no blanking by using
SOC.BLANKING.BLANKMODE
. If
SOC.BLANKING.BLANKMODE
is not
00b (disabled), then the blanking time may be configured to be between 100ns and 6000ns by setting the
value in
SOC.BLANKING.BLANKTIME
.
The comparator hysteresis may be configured independently for rising and falling input (asymmetric and
bi-directional). To set the comparator hysteresis scale for AIO7, set
SOC.SPECCFG0.HYSMODE
and to
set the hysteresis level set
SOC.SPECCFG0.AIO7HYS
.
The output polarity of the comparator may be selected by using
SOC.CFGAIO7.POL7
(0b: active-high; 1b:
active-low).
The output of the comparator may be sent to the digital bus DB1 to DB7 or to
SOC.DINSIG1.DIN7
by using
SOC.CFGAIO7.MUX7
.
9.16.4.3 I/O and Interrupts
In this mode, the digital input state and input interrupts are also available. To enable interrupts for low to
high transitions on AIO7, set
SOC.SIGINTEN.AIO7REINTEN
to 1b. To enable interrupts for high to low
transitions on AIO7, set
SOC.SIGINTEN.AIO7FEINTEN
to 1b. When the edge is detected, an interrupt will
be asserted on IRQ2 to the MCU. The interrupt status can be monitored by reading
SOC.SIGINTF.AIO7INT
and cleared by writing
SOC.SIGINTF.AIO7INTF
to 1b.
9.16.5 AIO7 Special Mode
AIO7 Special Mode is typically used for BEMF applications that need to measure the zero-cross
threshold of the phase voltage for motor commutation. In special mode, the CAFE can be
configured to internally generate a virtual center-tap voltage as a comparator reference for the
phase voltages.
Set
SOC.CFGAIO7.MODE7
= 11b to use AIO<9:7> in special mode. In special mode the AIO7 special
mode comparator is enabled.
9.16.5.1 Comparator Reference
In special mode, the comparator reference may be selected from AB<3:1>, AIO8, AIO9 or from a
programmable comparator threshold voltage (VTHREF). AB1 is used as the virtual center-tap for BEMF
zero-cross applications.
Set
SOC.SPECCFG2.SMUXAIO7
to select the comparator reference. To select the VTHREF comparator
threshold use
SOC.DOUTSIG0.VTHREF
to select a value from the following:
•
00b: 0.1V
•
01b: 0.2V
•
10b: 0.5V
•
11b: 1.25V
9.16.5.2 Comparator Configuration
The AIO7 comparator has programmable blanking time and hysteresis modes.
