6bc17e3211
Though there were issues with this sample before e959386bd2 ("samples:
servo_motor: cleanups and changes"), that commit introduced further
bugs. This happened because the new pwm-servo alias that commit
switched to wasn't provided by any boards, so it wasn't built in CI.
Before that, however, the recommendation to use bbc_microbit in the
sample documentation was also buggy in a couple of ways:
1. bbc_microbit doesn't have the pwm-0 alias the sample
previously required, so it didn't build on that board
2. the documentation's comment to use pin 0 on the edge connector
is wrong; PWM channel 0 is wired to GPIO P0.0 on the SoC,
which is actually pin 21 on the connector
Fix it all up.
Tested on bbc_microbit. I verified the pinout and also made sure that
the sample correctly generates pulses from 700 to 2300 usec.
Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
69 lines
1.8 KiB
ReStructuredText
69 lines
1.8 KiB
ReStructuredText
.. _servo-motor-sample:
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Servomotor
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##########
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Overview
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********
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This is a sample app which drives a servomotor using PWM.
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The sample rotates a servomotor back and forth in the 180 degree range with a
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PWM control signal.
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This app is targeted for servomotor ROB-09065. The corresponding PWM pulse
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widths for a 0 to 180 degree range are 700 to 2300 microseconds, respectively.
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Different servomotors may require different PWM pulse widths, and you may need
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to modify the source code if you are using a different servomotor.
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Requirements
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************
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You will see this error if you try to build this sample for an unsupported
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board:
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.. code-block:: none
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Unsupported board: pwm-servo devicetree alias is not defined
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The sample requires a servomotor whose signal pin is connected to a PWM
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device's channel 0. The PWM device must be configured using the ``pwm-servo``
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:ref:`devicetree <dt-guide>` alias. Usually you will need to set this up via a
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:ref:`devicetree overlay <set-devicetree-overlays>` like so:
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.. code-block:: DTS
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/ {
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aliases {
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pwm-servo = &some_pwm_node;
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};
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};
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Where ``some_pwm_node`` is the node label of a PWM device in your system.
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See :zephyr_file:`samples/basic/servo_motor/boards/bbc_microbit.overlay` for an
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example.
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Wiring
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******
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BBC micro:bit
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=============
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You will need to connect the motor's red wire to external 5V, the black wire to
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ground and the white wire to the SCL pin, i.e. pin 21 on the edge connector.
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Building and Running
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********************
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The sample has a devicetree overlay for the :ref:`bbc_microbit`.
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This sample can be built for multiple boards, in this example we will build it
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for the bbc_microbit board:
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.. zephyr-app-commands::
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:zephyr-app: samples/basic/servo_motor
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:board: bbc_microbit
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:goals: build flash
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:compact:
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