Timer predicates

The commands are mentioned below:

1. delay(t): Used to apply a delay of t milliseconds.
   • t: Time in milliseconds.
2. delayMicroseconds(t): Used to apply a delay of t microseconds.
   • t: Time in microseconds.
3. millis(T): It returns a number (T) representing the number of milliseconds since the program called one of the AgPi functions. It returns an unsigned 32-bit number which wraps after 49 days.
   • T: Time in milliseconds returned by the function.
4. micros(T): It returns a number representing the number of microseconds since the program called one of the AgPi functions. It returns an unsigned 32-bit number which wraps after approximately 71 minutes.
   • T: Time in microseconds returned by the function.

Example for LED blinking:

• Commect a LED to Raspberry Pi at GPIO pins 1 (HIGH) and 0 (LOW).
• Write the following code in a prolog file(in the working directory).
  Blink_Led
• Now start prolog with sudo permission(very important):
  $ sudo swipl
• Consult the platform_pi.pl using:
  ?- consult('platform_pi.pl').
  This will load all of the Tartarus predicates.
• Execute the command:
  ?- start_peripherals.
• Execute the following command to see the LED blink and the output of millis command on terminal.
  ?- start.