Embedian, Inc.
157
SMARC-iMX8MM Computer on Module User’s Manual
v. 1.2
When
main
power
is
supplied
from
the
carrier,
a
voltage
detector
will
assert
VIN_PWR_BAD#
signal
to
tell
the
module
and
carrier
that
the
power
is
good.
This
signal
will
turn
on
the
PMIC
on
module
to
power
on
the
module.
Carrier
power
circuits
in
the
carrier
Power
domain
should
not
power
up
unless
the
module
asserts
CARRIER_PWR_ON
.
The
module
signal
CARRIER_PWR_ON
exists
to
ensure
that
the
module
is
powered
before
the
main
body
of
carrier
circuits
(those
outside
the
power
and
power
control
path
on
the
carrier).
The
main
body
of
carrier
board
circuits
will
not
be
powered
until
the
module
asserts
the
CARRIER_PWR_ON
signal
being
correct.
Module
hardware
will
assert
CARRIER_PWR_ON
when
all
power
supplies
necessary
for
module
booting
are
ready.
The
module
will
continue
to
assert
signal
RESET_OUT#
after
the
release
of
CARRIER_PWR_ON
,
for
a
period
sufficient
to
allow
carrier
power
circuits
to
come
up.
When
Carrier
power
is
ready,
it
will
assert
RESET_IN#
to
inform
module
booting
up.
If
users
would
like
to
have
SD
boot
up,
SDIO_PWR_EN
signal
have
to
be
pull
up
to
3.3V
on
carrier.
Module
and
carrier
power
supplies
will
not
be
enabled
if
the
VIN_PWR_BAD#
is
held
low
by
carrier.
It
is
a
power
bad
indication
signal
from
carrier
and
is
200k
pull
up
to
VDD_IN
on
module.
