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keyboard

related to keyboard<br>functions of keyboard

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keyboard

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  1. Post.Graduate gulberge College for women, lahore Submitted to : Ma'am Ansa Maheen Subject: Assembly language(major) Session: 2019- 2023 Presentation weak: 13

  2. Group 4 Presentation Submitted by: Sidra Tahir 1922110043 Taimul Tosha 19221146 Nayyab Mir 1922110025 Saira saif 1922110034 Ruqia Naz 1922110032

  3. keyboard A computer keyboard is a typewriter-style device which uses an arrangement of buttons or keys to act as mechanical levers or electronic switches.

  4. Categories of keyboard

  5. • Typing (alphanumeric) keys. These keys include the same letter, number, punctuation, and symbol keys found on a traditional typewriter. • Control keys. These keys are used alone or in combination with other keys to perform certain actions. The most frequently used control keys are Ctrl, Alt, the Windows logo key Picture of the Windows logo key, and Esc. • Function keys. The function keys are used to perform specific tasks. They are labeled as F1, F2, F3, and so on, up to F12. The functionality of these keys differs from program to program. • Navigation keys. These keys are used for moving around in documents or webpages and editing text. They include the arrow keys, Home, End, Page Up, Page Down, Delete, and Insert. • Numeric keypad. The numeric keypad is handy for entering numbers quickly. The keys are grouped together in a block like a conventional calculator or adding machine.

  6. Keyboard Scan codes:- • Each key on keyboard is assigned a unique number called a scan code. • When a key is pressed,the keyboard circuit sends corresponding scan code to computer. • It’s value starts with 1. • The data from a keyboard comes mainly in the form of scancodes. • It is produced by key presses or used in protocol by the computer. • To indicate key’s release, keyboard circuit sends another code called break code. • By changing the msb, to 1 that code is called make code. • E.g:-Make code of escape key is 01h and break code is 81h.

  7. Table of scan code for Shift and Functions Keys:-

  8. Keyboard Buffer A keyboard buffer is a very small partition of memory that is usually stored in computer memory capture s all the keystrokes made on a keyboard in random access memory(RAM) and Keystrokes are stored because there is slight delay between when the key is pushed and when it displays on the screen.By capturing the keystroke,processing is easier and more accurate for the computer.

  9. How the computer accepts input from the keyboard?

  10. keyboard operation DEFINITION: “The keyboard operation which is used in the doing work and make easy for us instead of mouse” vStandard characters: A-Z, a-z,0-9,%,$,#. vExtended function key: • Function keys: F1,F2..Shift-F1.. • Numeric keypad keys: Home,End, Arrows, Page Up, Page Down. vSpecial keys: • Alt • Ctrl • and Shift

  11. OPERATIONS OF KEYBOARD shortcut key operation Description Shortcut key operation Description Ctrl+Z : , Ctrl + Z is a lifesaver. Undo. Irrespective of what you are doing, or where you are doing it Alt + Tab : Switch Screen/Tabs. Ctrl + A : Select All. ... Ctrl + Alt + Del : Task Manager. .. Ctrl + C : Copy. ... Alt + F4 : Close App. Ctrl + V : Paste. ... Ctrl + X : Cut. ...

  12. Shortcut key Operation Description Some Usefull Operation Of Keyboard In Daily Life In Your Work Focuses the next control element. Tab key Activates the selected button. Spacebar Enter Activates buttons or menu items and opens objects Shift + tab Focuses the previous control element. Context menu key and Shift + F10 Opens the context menu for the selected object (if available). Arrow keys, Pos1, END Navigates in toolbars, lists and tree views.

  13. INT 16H INSTRUCTION DEFINITION: “The int 16h interrupt is used to controlled the keyboard in the system. This interrupt is usually accessed by the DOS(disk operating system) interrupt 21h but can also accessed directly.”

  14. Reasons of using INT 16h • In 16 int , we use only 00h function . • When we use 16 int in operating system , when we run code then any code run perfectly without any error . • 16 int is slow. • We don’t need command prompt while using 16 INT in operating system.

  15. PROGRAM Q: Move the cursor to the upper left corner if the F1 key is pressed, to the lower right crner if any other function key is pressed. If a character key is pressed, do nothing.

  16. Solution: • MOV AH, 0 ; read keystroke function • iNT 16h ; AL= ASCII code or 0 , • ; AH= scan code • OR AL, AL ; AL=0 ( function key) ? • JNE EXIT ; no , character key • CMP AH,3BH ; scan code for F1 • JE F1 ;yes go to move curso •; Other function key: • MOV DX,184FH ; lower right corner • JMP EXECUTE ; go to move cursor •F1: • XOR DX,DX ; upper left corner •EXECUTE : • MOV AH, 2 ; move cursor function • XOR BH, BH ; page 0 • INT 10 H ; move cursor •EXIT :

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