Configure an ESP32 Board (Micro-RDK)

To add an esp32 board, navigate to the CONFIGURE tab of your machine’s page in the Viam app and select JSON mode.

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

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

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

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:

i2cs

The following properties are available for i2cs:

digital_interrupts

The following properties are available for digital_interrupts:

PWM signals on esp32 pins

You can set PWM frequencies with Viam through the GPIOPin API. A configured esp32 board can support a maximum of four different PWM frequencies simultaneously, as the boards only have four available timers.

For example:

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

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

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

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

1. 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.
2. 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.