Data Processing Transfer Sequence in CPU for Keyboard Input

In summary: So sorry for the confusion--I think the authors of the textbook may have gotten a little too caught up in the technology of that time period and forgot to update it!
  • #1
Ali Inam
99
0
When the data reaches the CPU via keyboard (suppose I typed the letter "A")


So, what are going to be the stages in the CPU. I mean where will data be going first ? !

The Cache ?
or RAM/ROM or registers ? !

I know about all the data processing functions they have, but, I am confused by the sequence of Data Transfer in order to see the letter "A" on the screen


Hopeful

:confused:
 
Technology news on Phys.org
  • #2
I think no one is answering because it's like explaining how dial tone happens--seems to simple to users, but there are a whole lot of things going on behind the scene. Simplified version: the characters you type go into an input buffer in memory (handled by the interface the keyboard is attached to, which could be either a USB port/driver, or an older PS/2 port/driver), and the keyboard has to raise an interrupt to let the CPU know that chars are incoming. The CPU then let's the operating system "handle" the characters that were typed, and the manner in which they show up on the screen depends on the user program (if any) which the operating system considered to be active at the time when you typed the characters. The operating system allows the appropriate user program to decide what to do with the input chars, whether to display them, and how.
 
  • #3
haha, this is too complex for a short answer.


read up on operating systems and architecture and you will understand *a little* more. The accurate short answer - it depends.
 
  • #4
I've reported this thread to get it merged with the other one in homework--hopefully, they'll determine whether it ought to be in this forum or the homework one. If this is homework, I would suspect it's asking you to elaborate upon the interrupt service routine for whichever processor you're studying.

There's a post over in EE wondering about the 'antiquated' microprocessor textbook they're studying, which dates from 1996 (the one I used in the course I took in 2004 dates to 1991!) The reality of the situation is that the fundamental basics of how things work in microprocessors haven't changed that much. The interrupt service routine is still how nearly every operating system handles a key press or mouse movement (outside of maybe some 'real-time' operating systems).
 
  • #5
There's a cpu inside the keyboard itself that constantly scans the keys for a change in state. When key press occurs, the keyboard buffers up the keycode for an "A" key being pressed and generates an interrupt. The PC's keyboard interrupt driver then inputs the buffered keystroke, and places it into a keyboard buffer, used by the BIOS or the OS. If there's is a pending request to read the keyboard buffer, the keycode is sent to the caller, otherwise it remains buffered. Once the request is made, the keycode is read. Somewhere in the process after this, the keycode is converted into an Ascii character. Then there's some program that sends the ascii character code to the video driver, either in text mode (MSDOS console mode), or graphics mode. In text mode the character is converted to a VGA code if needed, then indexes into a bit pattern matrix in the video cards font table to convert it into an bit image that it then displayed on the screeen. In graphics mode, the font pattern data is from the OS as opposed to the video cards bios.
 
  • #6
The main problem that I got was in an Exam


They asked about the processing which occurs inside the CPU after the data leaves the keyboard.

I knew waht happens, but, unfortunately, got stucked in the end part of the question in which they had written in brackets that they needed the whole process in a proper sequence.

On that point, I started to think, WHICH DEVICE IS FIRST ? !

I thought it was RAM

But I then had an idea about the Level 1 cache because it is on the microprocessor,

In the END !

I came up with the sequence as
ROM
CACHE
RAM
REGISTERS

:blushing:
 

What is data processing transfer sequence in CPU for keyboard input?

Data processing transfer sequence in CPU for keyboard input refers to the steps that the central processing unit (CPU) takes to process data received from a keyboard. This includes receiving the input, converting it into binary code, and transferring it to the appropriate memory location for further processing.

How does the CPU receive keyboard input?

The CPU receives keyboard input through an input/output (I/O) controller, which is connected to the keyboard via a cable. When a key is pressed, an electrical signal is sent to the I/O controller, which then sends the input to the CPU for processing.

What happens to the keyboard input in the CPU?

Once the CPU receives the keyboard input, it goes through a data processing transfer sequence. The input is first converted from its original form (such as letters or numbers) into binary code, which is a series of 0s and 1s that the CPU can understand. The binary code is then transferred to the appropriate memory location for further processing.

What is the role of the memory in data processing transfer sequence in CPU for keyboard input?

The memory plays a crucial role in data processing transfer sequence in CPU for keyboard input. It is responsible for storing the binary code received from the keyboard and sending it to the CPU for further processing. The memory also stores the processed data and makes it available for use by other components of the computer.

Can the data processing transfer sequence in CPU for keyboard input be changed?

Yes, the data processing transfer sequence in CPU for keyboard input can be changed. This can be done by modifying the software that controls the transfer of data from the keyboard to the CPU. However, any changes made should be carefully considered and tested to ensure they do not cause any errors or malfunctions in the system.

Similar threads

  • Programming and Computer Science
2
Replies
48
Views
4K
  • Sticky
  • Programming and Computer Science
Replies
13
Views
4K
  • Programming and Computer Science
Replies
18
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
7
Views
3K
  • Computing and Technology
Replies
10
Views
2K
  • STEM Educators and Teaching
Replies
5
Views
512
  • Programming and Computer Science
Replies
5
Views
3K
  • Computing and Technology
Replies
15
Views
1K
  • Programming and Computer Science
Replies
6
Views
1K
Back
Top