Embedian, Inc.
160
SMARC-iMX8MM Computer on Module User’s Manual
v. 1.2
4.5
Power
Sequences
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
enable
the
PMIC
on
module
to
power
on
the
module.
The
module
will
not
power
up
if
the
module
receives
a
low
‐
active
VIN_PWR_BAD#
signal.
The
SMARC
‐
iMX8MM
module
starts
asserting
CARRIER_PWR_ON
as
soon
as
the
main
voltage
supply
being
applied
to
the
module
and
all
power
supplies
necessary
for
module
booting
are
up.
This
is
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
module
will
continue
to
assert
signal
RESET_OUT#
after
the
release
of
CARRIER_PWR_ON
,
for
a
period
sufficient
time
(at
least
10ms)
to
allow
carrier
power
circuits
that
the
peripheral
supplies
need
to
ramp
up.
The
peripheral
power
rails
on
the
carrier
board
need
to
ramp
up
in
a
correct
sequence.
The
sequence
starts
normally
with
the
highest
voltage
(e.g.
5V)
followed
by
the
lower
voltages
(e.g.
3.3V
then
1.8V
and
so
on).
Peripherals
normally
require
that
a
lower
voltage
rails
is
never
present
if
a
higher
rail
is
missing.
Check
the
datasheet
of
all
peripheral
components
on
the
carrier
board
for
a
proper
sequencing.
The
SMARC
‐
iMX8MM
modules
guarantees
to
apply
the
reset
output
RESET_OUT#
not
earlier
than
100ms
after
the
CARRIER_PWR_ON
goes
high.
This
gives
the
carrier
board
a
sufficient
time
for
ramping
up
all
power
rails.
SDIO_PWR_EN
signal
have
to
be
pull
up
to
3.3V
on
carrier
if
users
would
like
to
have
SD
boot
up
functionality.