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M20 Hardware Design
VDD_EXT
O
Supply 2.8V voltage for
external
measuring this pin, customer
can
system is power on or off.
When the voltage is low, the
system
Otherwise, the system is
power on.
GND
Digital ground
Power on or power off
PIN NAME
I/O
DESCRIPTION
PWRKEY
I
Voltage input for power
on/off key. PWRKEY should
be pulled down to turn on or
turn
Customer
pressing this key for a
moment when turn on or turn
off the module.
Emergency shutdown
PIN NAME
I/O
DESCRIPTION
EMERG_OF
I
Voltage input for emergency
F
shutdown under emergent
situation.
should be pulled down for at
least 20ms to shutdown the
system in emergency. The
module
PWRKEY operation.
Audio interfaces
PIN NAME
I/O
DESCRIPTION
MIC1P
I
Audio
MIC1N
Positive and negative voice
input.
M20_HD_V1.01
circuit.
By
judge
whether
the
is
power
off.
off
the
system.
should
keep
EMERG_OFF
can
restart
by
input
channel
1.
Vmax=2.9V
Vmin=2.7V
Vnorm=2.8V
Imax=20mA
DC CHARACTERISTICS
VILmax=0.3*VBAT
VIHmin=0.7*VBAT
VImax=VBAT
DC CHARACTERISTICS
VILmax=0.4V
VIHmin=2.2V
V
max=2.8V
open
DC CHARACTERISTICS
Audio DC Characteristics
refer to chapter 3.10
1.If
unused,
keep this pin
open.
2.
Recommend
to
add
a
2.2~4.7uF
bypass
capacitor,
when
using
this pin for
power supply.
COMMENT
Pull
up
to
VBAT
internally.
COMMENT
Open
drain/collecto
r
driver
required
in
cellular
device
application.
If
unused,
keep this pin
open.
COMMENT
No
internal
microphone
bias supply. If
unused
keep
these
pins
open.
- 19 -
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