定时器#

介绍#

The timer class is derived from the brain base class and provides functionality for measuring elapsed time, allowing you to track durations and schedule time-based events within a VEX V5 program.

使用权#

Brain.Timer

笔记#

  • Brain.Timer is an instance of the timer class and provides the same functionality.

例子#

/* This constructor is required when using VS Code.
A Brain is generated automatically at the start of
VEXcode projects. */

// Create the V5 Brain
brain Brain = brain();


// Display the timer as it ticks up
while (true) {
  Brain.Screen.clearScreen();
  Brain.Screen.setCursor(1, 1);
  Brain.Screen.print("Time: %.2f", Brain.Timer.time());

  wait(50, msec);
}

成员功能#

The timer class includes the following member functions:

  • clear — Resets the timer to zero.

  • time — Returns the elapsed time since the timer started.

  • event — Calls a function after a specified number of milliseconds, with optional arguments.

Before calling any sdcard member functions, a brain instance must be created, as shown below:

// Create the V5 Brain
brain Brain = brain();

清除#

将计时器的当前值重置为零。之后，计时器立即从零开始重新计数。

Available Functions 
void clear();
Parameters

此函数不接受任何参数。

Return Values

此函数不返回值。

Examples 
while (true) {
  // Reset the timer every time the screen is pressed
  if (Brain.Screen.pressing()) {
    Brain.Timer.clear();
  }
  Brain.Screen.clearScreen();
  Brain.Screen.setCursor(1, 1);
  Brain.Screen.print("Time: %.2f", Brain.Timer.value());
  wait(50, msec);
}

时间#

返回计时器的当前值。

Available Functions

1 — 返回经过的时间（以毫秒为单位）。

uint32_t time() const;

2 — 返回以指定时间单位计算的经过时间。

double time(
    timeUnits units ) const;
Parameters

范围

类型

描述

units

timeUnits

The units used to return the elapsed time:

  • seconds / sec — seconds
  • msec — milliseconds
Return Values

  • The parameterless function (1) returns a uint32_t representing the elapsed time in milliseconds.

  • The function with a timeUnits parameter (2) returns a double representing the elapsed time in the specified units.

Notes

  • 项目开始时，计时器开始计时。

  • Calling clear resets the timer value to zero.

Examples 
// Display the timer as it ticks up
while (true) {
  Brain.Screen.clearScreen();
  Brain.Screen.setCursor(1, 1);
  Brain.Screen.print("Time: %.2f", Brain.Timer.time());

  wait(50, msec);
}

事件#

注册一个回调函数，该函数将在指定的延迟后执行。

Available Functions

1 — 注册一个回调函数，使其在指定的延迟后运行，并将用户定义的值传递给该回调函数。

static void event(
    void (*callback)(void*),
    uint32_t value );

2 — 注册一个回调函数，使其在指定的延迟后运行。

static void event(
    void (*callback)(void),
    uint32_t value );
Parameters

范围

类型

描述

callback

void ()(void)

一个将在指定延迟后调用并接收用户定义参数的函数。

callback

void (*)(void)

将在指定延迟时间后调用的函数。

value

uint32_t

回调函数执行前的延迟时间（以毫秒为单位）。
Return Values

此函数不返回值。

Notes

  • 此函数会安排一次性回调；它不会自动重复执行。

  • The callback function must return void.

  • 可以同时安排多个活动。

Examples 
// Create a function to turn the screen orange
void turnOrange() {
  Brain.Screen.clearScreen(orange);
}


// Call turnOrange after 2 seconds
Brain.Timer.event(turnOrange, 2000);
On this page