Embedian, Inc.
24
SMARC-iMX8MM Computer on Module User’s Manual
v. 1.2
2.1.4.
Onboard
Storage
The
SMARC
‐
iMX8MM
module
supports
a
16GB
eMMC
flash
memory
device,
and
a
32Kb
I2C
serial
EEPROM
on
the
Module
I2C_GP
(I2C3)
bus.
The
device
used
is
an
On
Semiconductor
24C32
equivalent.
The
Module
serial
EEPROM
is
intended
to
retain
Module
parameter
information,
including
a
module
part
number,
revision
number
and
serial
number.
The
Module
serial
EEPROM
data
structure
conforms
to
the
PICMG®
EEEP
Embedded
EEPROM
Specification.).
The
onboard
16GB
eMMC
flash
is
used
as
boot
media
and
operating
systems.
The
module
will
always
boot
up
from
the
onboard
eMMC
flash
first.
The
firmware
in
eMMC
flash
will
read
the
BOOT_SEL
configuration
from
the
boot
selection
and
boot
up
the
devices
from
that
selected.
2.1.5.
Clocks
A
24
MHz
oscillator
is
used
as
the
primary
clock
source
for
the
PLLs
to
generate
the
clock
for
CPU,
BUS,
and
high
‐
speed
interfaces.
For
fractional
PLLs,
the
24
MHz
clock
from
the
oscillator
can
be
directly
used
as
the
PLL
reference
clock.
A
32.768
KHz
clock
is
required
for
the
i.MX8M
Mini
CPU
RTC
(Real
Time
Clock)
and
external
(S
‐
35390A)
RTC.
A
24Mhz
crystal
is
used
on
on
‐
module
USB2514
USB
hub.
A
27
MHz
HCSL
oscillator
is
used
as
the
reference
clock
for
PCIe
clock
generator
.
The
Qualcomm
AR8035
PHY,
PCIe
HCSL
clock
generator
and
Microchip
CAN
controllers
are
provided
with
a
25
MHz
clock
using
a
crystal
in
normal
oscillation
mode.
