Edit

Configure an ESP32 Board (viam-micro-server)

REQUIREMENTS

Follow the setup guide to install and run viam-micro-server before configuring an esp32 board.

Viam recommends purchasing the ESP32 with a development board. The following ESP32 microcontrollers are supported:

ESP-32-WROVER Series

Your microcontroller should have at least the following resources available to work with viam-micro-server:

2 Cores + 384kB SRAM + 2MB PSRAM + 4MB Flash

To test your board as you configure it, power it on. If you plan to connect hardware to the board’s pins, connect the hardware while it’s powered off. To configure an esp32 board, navigate to the CONFIGURE tab of your machine’s page in the Viam app and select JSON mode.

Info

Theesp32 board model is not currently available as a built-in option in the Viam app, so you cannot use Builder mode to configure this board.

Copy the following JSON template and paste it into your configuration inside the "components" array:

JSON Template
JSON Example

{
  "name": "<your-board-name>",
  "model": "esp32",
  "type": "board",
  "namespace": "rdk",
  "attributes": {
    "pins": [
      <int>
    ],
    "analogs": [
      {
        "pin": <int>,
        "name": "<your-analog-name>"
      }
    ],
    "digital_interrupts" : [
        {
         "pin": <int>
        }
    ]
  },
  "depends_on": []
}

{
  "name": "board",
  "model": "esp32",
  "type": "board",
  "namespace": "rdk",
  "attributes": {
    "pins": [15, 34],
    "analogs": [
      {
        "pin": "34",
        "name": "sensor"
      }
    ],
    "digital_interrupts": [
      {
        "pin": 4
      }
    ]
  },
  "depends_on": []
}

Edit and fill in the attributes as applicable. Click the Save button in the top right corner of the page.

The following attributes are available for esp32 boards:

Name	Type	Required?	Description
`analogs`	array	Optional	Attributes of any pins that can be used as analog-to-digital converter (ADC) inputs. See configuration info.
`i2cs`	array	Optional	Any Inter-Integrated Circuit (I²C) pins’ bus index and name. See configuration info.
`digital_interrupts`	array	Optional	Any digital interrupts’ GPIO number. See configuration info.
`pins`	array	Optional	The GPIO number of any GPIO pins you wish to use as input/output with the board API.

Any pin not specified in either "pins" or "digital_interrupts" cannot be interacted with through the board API. Interaction with digital interrupts is only supported with the board API; these digital interrupts cannot be used as software interrupts in driver implementations.

`analogs`

The following properties are available for analogs:

Name	Type	Required?	Description
`name`	string	Required	Your name for the analog reader.
`pin`	integer	Required	The GPIO number of the ADC’s connection pin, wired to the board.

`i2cs`

The following properties are available for i2cs:

Name	Type	Required?	Description
`name`	string	Required	`name` of the I²C bus.
`bus`	string	Required	The index of the I²C bus. Must be either `i2c0` or `i2c1`.
`data_pin`	integer	Optional	The GPIO number of the data pin. Default: `11`.
`clock_pin`	integer	Optional	The GPIO number of the clock pin. Default: `6`.
`baudrate_hz`	integer	Optional	The baudrate in HZ of this I²C bus. Default: `1000000`
`timeout_ns`	integer	Optional	Timeout period for this I²C bus in nanoseconds. Default: `0`

`digital_interrupts`

The following properties are available for digital_interrupts:

Name	Type	Required?	Description
`pin`	integer	Required	The GPIO number of the board’s GPIO pin that you wish to configure the digital interrupt for.

PWM signals on `esp32` pins

You can set PWM frequencies with Viam through the GPIOPin API. Refer to the Espressif documentation for valid frequencies and duty resolutions. A configured esp32 board can support a maximum of four different PWM frequencies simultaneously, as the boards only have four available timers.

For example:

Pin	PWM Frequency (Hz)
12	2000
25	3000
26	5000
32	6000

At this point, if you want to add another PWM signal, you must do the following:

Set the PWM frequency before the duty cycle.
Set the PWM frequency to one of the above previously set frequencies.

For example, you can set pin 33 to 2000 Hz:

Pin	PWM Frequency (Hz)
12, 33	2000
25	3000
26	5000
32	6000

Then, follow these requirements to change the PWM frequencies of a pin:

If no other pins have a signal of the same frequency (for example, pins 25, 26, and 32), you can freely change their PWM frequency.
If one or more pins are sharing the old frequency (for example, pins 12 and 33):
1. If there are less than 4 active frequencies, you can change the PWM frequency freely because there will be a timer available.
2. If there are already 4 active frequencies, changing the PWM frequency of the pin will raise an error because there are no timers available. Free a timer by setting the PWM frequencies of all of the pins to 0.

Troubleshooting

If your board is not working as expected, follow these steps:

Check your machine logs on the LOGS tab to check for errors.
Review this board model’s documentation to ensure you have configured all required attributes.
Check that all wires are securely connected.
Click on the TEST panel on the CONFIGURE or CONTROL tab and test if you can use the board there.

If none of these steps work, reach out to us on the Community Discord and we will be happy to help.

Next steps

For more configuration and usage info, see:

Configure an ESP32 Board (viam-micro-server)

REQUIREMENTS

Info

analogs

i2cs

digital_interrupts

PWM signals on esp32 pins