2.1.9 Toggling All Port Pins

Hello Readers:

I have started this blog to show you Embedded C programming for 8051 family microcontroller using KEIL compiler. The KISS philosophy is used to write this tutorial. What is KISS? Keep It Simple, Stupid!

2. Manipulating Port Pins

This section teaches you how to manipulate port pins bytewise and bitwise.

2.1 Bytewise [all port pins-8bits]

First we see how to control port pins bytewisely.

2.1.9  Toggling All Port Pins

This program shows how to send data to all three available ports and can used to test them by connecting LEDs. Here all three ports are toggling infinitely.  

Start KEIL V4.01 and close projects, if any are open. Now start new project with Device -> Generic->8051 [all variants] for general 8051 family target chip. Add a new text file, name it Pgm_219.C and add it to above created project as a source file. It is time to add code to Pgm_219.C, so type below shown code in it.

Code explanation:

Line 12, 13 & 14: Sending 0x55 to Port 1,2 & 3.

Line 15: 250 Millisecond Delay.

Line 12, 13 & 14: Sending 0xAA to Port 1,2 & 3.

 

Below is the flow chart diagram of program PGM_219.C.

 

 

After typing the code, press F7 or click Project->Build Target for building the source code. If there are no typical errors file will build successively and shows zero errors and zero warnings.

Now enter into debug mode by pressing Ctrl+F5 or click Debug->Start/Stop Debug Session menu. Our program is sending 0x55 & 0xAA numbers in binary form to Port 1, 2 & 3 continuously. So we want to watch the Ports 1, 2 & 3 pins while running this program for toggling values. To get Port 1, 2 & 3 tabs click Peripherals->I/O Ports->Port 1, Peripherals->I/O Ports->Port 2 and Peripherals->I/O Ports->Port 3 menus.

Run the program by pressing F5 or clicking Debug->Run. You can see the toggling values between 0x55 and 0xAA on Ports 1, 2 & 3 tabs continuously in binary form. If you generate HEX file of this program, burn it into your target chip’s memory using suitable uploader and connecting 8 LEDs to all Ports you can watch LEDs toggling in binary form. To stop running the program press red ‘x’ mark icon or click Debug->Stop.

To get back the compile mode press Ctrl+F5 or click Debug->Start/Stop Debug Session menu.  

<End of 2.1.9 Toggling All Port Pins >

...till next post bye-bye & take care.