How to use KEIL Software. The KEIL SOFTWARE is used as compiler for both assembler and C Language program. Write your program with either C program of assembly, the KEIL software converts high level language to machine code. Also See my video tutorial at the bottom of this post If your want to download KEIL Software: Click Here. After download and installation completed yourself, Please follow my below given graphical tutorial and it is very usefull to understand how to compiling in it with your final HEX code the is your program machine code. Double Click your shortcut icons. Now your keil software is running. CLICK PROJECT > NEW uVISION PROJECT then your storage location (Desktop) Open New Folder with name >File Name Then save. Next select your Device (Which family) like ATmel 89c51 Then OK. Select the prompt NO. Select File> New File Save your file with .c (With your program type) (IMPORTANT: if your program like C use .c or your Program is assembly like .asm) Save your file. now your codes are highlighted according to syntex SELECT Target and go > Options for Group the click. Her you want to change your microcontroller operating frequency (For Atmel 89c51 like 11.0592Mhz) Then Click OUTPUT> Tick the create HEX File radio button. Then click OK. Then click source Group> and select your already saved file like .C or .asm the click to add. Click Translate,Rebuld and Build buttons Finally you get your program HEX Codes. Thank your for more details Click here.