Analog In

Introduction

The analog_in class is used to read analog input signals from devices connected to a VEX EXP 3-Wire port. It provides access to the current analog value and allows callback functions to be registered for value changes.

Class Constructors

analog_in( 
    triport::port &port );

Class Destructor

Destroys the analog_in object and releases associated resources.

~analog_in();

Parameters

Parameter	Type	Description
port	triport::port&	The 3-Wire Port that the Analog Input is connected to, written as Brain.ThreeWirePort.X or ExpanderName.X, where X is the port letter (for example, Brain.ThreeWirePort.A or Expander1.A).

Example

// Create the analog_in instance on 3-Wire Port A
analog_in AnalogInA = analog_in(Brain.ThreeWirePort.A);

Member Functions

The analog_in class includes the following member functions:

• value — Returns the value of the Analog Input device.

• changed — Registers a callback function for when the analog input value changes.

Before calling any analog_in member functions, an analog_in instance must be created, as shown below:

/* This constructor is required to use an
Analog Input device. Replace the values
as needed. */

// Create the analog_in instance on 3-Wire Port A
analog_in AnalogInA = analog_in(Brain.ThreeWirePort.A);

value

Returns the current value of the analog input.

Available Functions

int32_t value( 
  analogUnits units );

Parameters

Parameter	Type	Description
units	analogUnits	The unit to represent the value: range8bit — 8-bit analog value (a value with 256 possible states) range10bit — 10-bit analog value (a value with 1024 possible states) range12bit — 12-bit analog value (a value with 4096 possible states) pct — percentage mV — millivolts

Return Values

This function returns the current value of the analog input.

Examples

// Get the current value of the Analog Input
int32_t value = AnalogInA.value();

changed

Registers a callback function to be called when the value of the analog input changes.

Available Functions

void changed( void (* callback)(void) );

Parameters

Parameter	Type	Description
callback	void (* callback)(void)	A function that will be called when the value of the analog input changes.

Return Values

This function does not return a value.

Examples

Define the callback function (outside of int main())

// Display a message when the input changes
void AnalogInputChanged() {
  Brain.Screen.print("analog input changed");
}

Register the callback inside int main()

int main() {
  /* vexcodeInit() is only required when using VEXcode.
  Remove vexcodeInit() if compiling in VS Code. */
  vexcodeInit();

  // Run AnalogInputChanged when the value of the
  // Analog Input changes
  AnalogInA.changed(AnalogInputChanged);
}