What is debugging?

Hello everyone,
I wanted to know the basics of debugging in embedded systems. How it can be done. What are the types of debugging. In keil there is a debugger built in. Also wen searched in web I found JTAG is widely used for debugging in embedded system. What is JTAG? What's the difference between debugging in keil and JTAG? Also there are various debuggers on eshops. Which one to purchase and how to learn debugging.Please need a elaborated answer for these questions. As I don't know abcd of debugging.

Debugging is the process of finding out why your program doesn't work

There is special hardware to let you see what is going in inside
the micro, this will help you see what is wrong.

This hardware is often expensive and will probably only confuse you more.
most people don't use it.

The best way to debug is in short steps.
Suppose your program to flash an LED using a timer does nothing.

Debug by writing code to just turn a LED on..
this tests the LED , the micro and the programmer.
Next write code to turn a LED on , then delay then off.

If it works you can move on to test the rest of the code bit by bit.

@ExperimenterUK

Thank you for your simple and useful explanation 😊 But in a product development there will be thousands of lines of codes i believe. How will the debugging done in that case? I mean in any company how will this be done?

I think the biggest code in embedded world today is Linux and for debugging Linux I use printk, so you can use printf or something you can print on uart.