Archives For I/O ports

Of all motors, step motor is the easiest to control. It’s handling simplicity is really hard to deny – all there is to do is to bring the sequence of rectangle impulses to one input of step controller and direction information to another input. Direction information is very simple and comes down to “left” for logical one on that pin and “right” for logical zero. Continue Reading…

Most projects you create with the 8051 microcontroller require some form of  display.  The most common way to accomplish this is with the LCD  (Liquid Crystal Display).  LCDs have become a cheap and easy way to get text display for an embedded system Common displays are set up as 16 to 20 characters by 1 to 4 lines. Continue Reading…

Relay interface on I/O ports

February 23, 2011 — 1 Comment

When a current flows through the coil, the resulting magnetic field attracts an armature that is mechanically linked to a moving contact.  The movement either makes or breaks a connection with a fixed contact.   When the current to the coil is switched off, the armature is returned by a force approximately half as strong as the magnetic force to its relaxed position.  Usually this is a spring, but the gravity is also used commonly in industrial motor starters. Continue Reading…