Example: GPIO4_D4
->
(
4
*
32
)
+
(
3
*
8
)
+
4
=
156
To enable a GPIO, write the Linux GPIO # to the special
export
file:
echo
156
> /
sys
/
class
/
gpio
/
export
ls
/
sys
/
class
/
gpio
/
gpio156
cat
/
sys
/
class
/
gpio
/
gpio156
/
direction
in
cat
/
sys
/
class
/
gpio
/
gpio156
/
value
0
To set the direction to output, write
out
in the GPIO’s direction file:
echo out
> /
sys
/
class
/
gpio
/
gpio156
/
direction
echo
1
> /
sys
/
class
/
gpio
/
gpio156
/
value
The GPIO will be set to a value of
1
(high at 3.3V).
3.15 Audio
The board provides two audio connectors for input and output.
Line-in
is on top and
Headphones
is on bottom of the
audio connector.
Fig. 3.13: Audio input/output port
Additionally, an expansion connector for I2S audio is available on the bottom row of the board:
Release v0.2-3-g574c114
Page
18
Содержание RK3399-Q7
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