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166 lines
5.5 KiB
Plaintext
166 lines
5.5 KiB
Plaintext
---
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id: gpio-peripherals
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title: Configuring GPIO Peripherals
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sidebar_label: Setup GPIO Peripherals
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slug: /hardware/peripheral/
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sidebar_position: 4
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---
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## Remote Hardware
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:::warning
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GPIO access is fundamentally dangerous because invalid options can physically damage or destroy your hardware. Ensure that you fully understand the schematic for your particular device before trying this as we do not offer a warranty. Use at your own risk.
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:::
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### Supported Operations
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- Set any GPIO
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- Read any GPIO
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- Receive notification of changes in any GPIO
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### Setup
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You can get the latest python tool/library with `pip3 install --upgrade meshtastic` on Windows/Linux/OS-X. See the [python section](/docs/software/python/cli/installation) for more details.
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To prevent access from untrusted users, you must first make a `gpio` channel that is used for authenticated access to this feature. You'll need to install this channel on both the local and remote node.
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The procedure using the python command line tool is:
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1. Connect local device via USB
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2. Create a GPIO channel:
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```shell
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meshtastic --ch-add gpio
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```
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3. If doing local testing, you may also want to change the speed of the channel:
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```shell
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meshtastic --ch-mediumfast
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```
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4. Check the channel has been created and copy the long "Complete URL" that contains all the channels on that device:
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```shell
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meshtastic --info
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```
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5. Connect the remote device via USB (or use the [remote admin](/docs/configuration/remote-admin) feature to reach it through the mesh)
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6. Set it to join the gpio channel you created:
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```shell
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meshtastic --seturl theurlyoucopiedinstep3
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```
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Now both devices should be able to talk over the `gpio` channel. Send a text message from one to the other to verify. Also run `--nodes` to verify the second node shows up.
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### Masks
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To determine the appropriate mask for the pin(s) that you want to know. The python program (and output) below might help:
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```python
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>>> for i in range(1,45):
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... print(f'GPIO:{i} mask:{hex(2**i)}')
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...
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GPIO:1 mask:0x2
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GPIO:2 mask:0x4
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GPIO:3 mask:0x8
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GPIO:4 mask:0x10
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GPIO:5 mask:0x20
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GPIO:6 mask:0x40
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GPIO:7 mask:0x80
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GPIO:8 mask:0x100
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GPIO:9 mask:0x200
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GPIO:10 mask:0x400
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GPIO:11 mask:0x800
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GPIO:12 mask:0x1000
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GPIO:13 mask:0x2000
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GPIO:14 mask:0x4000
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GPIO:15 mask:0x8000
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GPIO:16 mask:0x10000
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GPIO:17 mask:0x20000
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GPIO:18 mask:0x40000
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GPIO:19 mask:0x80000
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GPIO:20 mask:0x100000
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GPIO:21 mask:0x200000
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GPIO:22 mask:0x400000
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GPIO:23 mask:0x800000
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GPIO:24 mask:0x1000000
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GPIO:25 mask:0x2000000
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GPIO:26 mask:0x4000000
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GPIO:27 mask:0x8000000
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GPIO:28 mask:0x10000000
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GPIO:29 mask:0x20000000
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GPIO:30 mask:0x40000000
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GPIO:31 mask:0x80000000
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GPIO:32 mask:0x100000000
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GPIO:33 mask:0x200000000
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GPIO:34 mask:0x400000000
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GPIO:35 mask:0x800000000
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GPIO:36 mask:0x1000000000
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GPIO:37 mask:0x2000000000
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GPIO:38 mask:0x4000000000
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GPIO:39 mask:0x8000000000
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GPIO:40 mask:0x10000000000
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GPIO:41 mask:0x20000000000
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GPIO:42 mask:0x40000000000
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GPIO:43 mask:0x80000000000
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GPIO:44 mask:0x100000000000
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```
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## Testing GPIO Operations
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You can programmatically do operations from your own python code by using the Meshtastic `RemoteHardwareClient` class. See the [Python API](/docs/software/python/cli/installation) documentation for more details.
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You can add a simple LED and resistor to validate that the GPIO operations work as expected. Use [this tutorial](https://www.instructables.com/Slide-Switch-With-Arduino-Uno-R3/) as a guide.
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### Requirements
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- (x2) Meshtastic devices (one device could be on a local computer, and the other one just has to be powered and is the one with the LED to be connected to it)
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- (x2) wires (black and yellow; they can be any color but typically black is used for ground)
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- (x1) LED
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- (x1) 220Ω resistor (somewhat optional, but recommended)
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- (x1) Breadboard (optional)
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### Preparation
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1. Disconnect the remote device from power (battery/usb)
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2. Connect the resistor to the longer (positive) lead of the LED and the yellow wire to the other end of the resistor
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3. Connect the other end of the yellow wire to a GPIO pin that will not cause any issues (ex: for TLoraV1, we can use GPIO21)
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4. Connect the black "ground" wire from the ground pin on the device (ex: for TLoraV1 it is the end pin next to the RST button) to the shorter (negative) lead of the LED
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5. Power on the device
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### Validation
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By default, the pin may be "off" or "on". (It will most likely "off".) See the steps below for running commands. In the example of GPIO21, the mask would be `0x200000`.
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## Using GPIOs from the Python CLI
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### Writing a GPIO
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```shell title="Example: turning 'on' GPIO4"
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meshtastic --port /dev/ttyUSB0 --gpio-wrb 4 1 --dest 28979058
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# Connected to radio
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# Writing GPIO mask 0x10 with value 0x10 to !28979058
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```
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### Reading a GPIO
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```shell title="Example: read GPIO4"
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meshtastic --port /dev/ttyUSB0 --gpio-rd 0x10 --dest 28979058
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# Connected to radio
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# Reading GPIO mask 0x10 from !28979058
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# GPIO read response gpio_value=16
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```
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:::note
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If the mask and the gpio_value match, then the value is "on". If the gpio_value is 0, then the value is "off".
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:::
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### Watching for GPIO Changes
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```shell title="Example: watching GPIO4 for changes"
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meshtastic --port /dev/ttyUSB0 --gpio-watch 0x10 --dest 28979058
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# Connected to radio
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# Watching GPIO mask 0x10 from !28979058
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# Received RemoteHardware typ=GPIOS_CHANGED, gpio_value=16
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# Received RemoteHardware typ=GPIOS_CHANGED, gpio_value=0
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# Received RemoteHardware typ=GPIOS_CHANGED, gpio_value=16
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# < press ctrl-c to exit >
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```
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