# fake Reference for the fake board model. Fake board. > Source: https://docs.viam.com/reference/components/board/fake/ The `fake` board returns incrementing values for digital interrupt ticks and analogs. Configure a `fake` board to test integrating a board into your machine without physical hardware: ### JSON Template ```json { "components": [ { "name": "", "model": "fake", "api": "rdk:component:board", "attributes": { "fail_new": }, "depends_on": [] } ] } ``` The following attributes are available for `fake` boards: | Name | Type | Required? | Description | | ---- | ---- | --------- | ----------- | | `fail_new` | bool | **Required** | If the fake board should raise an error at machine start-up. | | `analogs` | object | Optional | Attributes of any pins that can be used as Analog-to-Digital Converter (ADC) inputs. See [configuration info](#analogs). | | `digital_interrupts` | object | Optional | Pin and name of any digital interrupts. See [configuration info](#digital_interrupts). | ## Attribute configuration Configuring these attributes on your board allows you to integrate [analog-to-digital converters](#analogs) and [digital interrupts](#digital_interrupts) into your machine. ### `analogs` An [analog-to-digital converter](https://www.electronics-tutorials.ws/combination/analogue-to-digital-converter.html) (ADC) takes a continuous voltage input (analog signal) and converts it to an discrete integer output (digital signal). ADCs are useful when building a robot, as they enable your board to read the analog signal output by most types of [sensors](/reference/components/sensor/) and other hardware components. To integrate an ADC into your machine, you must first physically connect the pins on your ADC to your board. Then, integrate `analogs` into the `attributes` of your board by following the **Config Builder** instructions or by adding the following to your board's JSON configuration: {{< tabs name="Configure an Analog Reader" >}} {{% tab name="Config Builder" %}} On your board's panel, click **Show more**, then select **Add analog**. Assign a name to your analog and then fill in the required properties outlined below. ![An example configuration for analogs.](/components/board/analogs-ui-config.png) {{% /tab %}} {{% tab name="JSON Template" %}} ```json {class="line-numbers linkable-line-numbers"} // "attributes": { ... , "analogs": [ { "name": "", "pin": "", "spi_bus": "", "chip_select": "", "average_over_ms": , "samples_per_sec": } ] ``` {{% /tab %}} {{% tab name="JSON Example" %}} ```json {class="line-numbers linkable-line-numbers"} { "components": [ { "model": "pi", "name": "your-board", "api": "rdk:component:board", "attributes": { "analogs": [ { "name": "current", "pin": "1", "spi_bus": "1", "chip_select": "0" }, { "name": "pressure", "pin": "0", "spi_bus": "1", "chip_select": "0" } ] } } ] } ``` {{% /tab %}} {{< /tabs >}} The following properties are available for `analogs`: | Name | Type | Required? | Description | | ---- | ---- | --------- | ----------- | |`name` | string | **Required** | Your name for the analog reader. | |`pin`| string | **Required** | The pin number of the ADC's connection pin, wired to the board. This should be labeled as the physical index of the pin on the ADC. |`chip_select`| string | **Required** | The chip select index of the board's connection pin, wired to the ADC. | |`spi_bus` | string | **Required** | The index of the SPI bus connecting the ADC and board. | | `average_over_ms` | int | Optional | Duration in milliseconds over which the rolling average of the analog input should be taken. | |`samples_per_sec` | int | Optional | Sampling rate of the analog input in samples per second. | #### Test `analogs` Once you have configured your analogs, open the board's **TEST** panel on the **CONFIGURE** or [**CONTROL**](/monitor/default-interface/#web-ui) tabs to monitor analogs. The numbers displayed next to each analog name represent the digital signal received from the analog inputs. {{}} ### `digital_interrupts` [Interrupts](https://en.wikipedia.org/wiki/Interrupt) are a method of signaling precise state changes. Configuring digital interrupts to monitor GPIO pins on your board is useful when your application needs to know precisely when there is a change in GPIO value between high and low. - When an interrupt configured on your board processes a change in the state of the GPIO pin it is configured to monitor, it ticks to record the state change. You can stream these ticks with the board API's [`StreamTicks()`](/reference/apis/components/board/#streamticks), or get the current value of the digital interrupt with [`Value()`](/reference/apis/components/board/#getdigitalinterruptvalue). - Calling [`GetGPIO()`](/reference/apis/components/board/#getgpio) on a GPIO pin, which you can do without configuring interrupts, is useful when you want to know a pin's value at specific points in your program, but is less precise and convenient than using an interrupt. Integrate `digital_interrupts` into your machine in the `attributes` of your board by following the **Config Builder** instructions, or by adding the following to your board's JSON configuration: {{< tabs name="Configure a Digital Interrupt" >}} {{% tab name="Config Builder" %}} On your board's panel, click **Show more**, then select **Add digital interrupt**. Assign a name to your digital interrupt and then enter a pin number. ![An example configuration for digital interrupts.](/components/board/digital-interrupts-ui-config.png) {{% /tab %}} {{% tab name="JSON Template" %}} ```json {class="line-numbers linkable-line-numbers"} // "attributes": { ... , "digital_interrupts": [ { "name": "", "pin": "" } ] ``` {{% /tab %}} {{% tab name="JSON Example" %}} ```json {class="line-numbers linkable-line-numbers"} { "components": [ { "model": "pi", "name": "your-board", "api": "rdk:component:board", "attributes": { "digital_interrupts": [ { "name": "your-interrupt-1", "pin": "15" }, { "name": "your-interrupt-2", "pin": "16" } ] } } ] } ``` {{% /tab %}} {{< /tabs >}} The following properties are available for `digital_interrupts`: | Name | Type | Required? | Description | | ---- | ---- | --------- | ----------- | |`name` | string | **Required** | Your name for the digital interrupt. | |`pin`| string | **Required** | The {{< glossary_tooltip term_id="pin-number" text="pin number" >}} of the board's GPIO pin that you wish to configure the digital interrupt for. | #### Test `digital_interrupts` Once you have configured your digital interrupts, open the board's **TEST** panel on the **CONFIGURE** or [**CONTROL**](/monitor/default-interface/#web-ui) tabs to monitor interrupt activity. The value displayed next to each interrupt name represents the total count of interrupts triggered by the corresponding digital interrupt. {{}}