Is there a good site / book / projects that explain what happens when we send some information from the keyboard to a device that is connected via a serial/usb port of the PC.
Say, for example, I hit the digit 6 for any device that is connected to my PC via the serial port or USB port or any other port and the device displays the digit 6 on the LCD or any other device that sets its time counter to 6 seconds, or makes sound for 6 seconds, etc....
I know there is a micro controller or some kind of PCBs on the electronic devices that understands any data that I send from the computer, but I would like to know what exactly is happening and how the devices understand the data that I send from the computer and convert it into the appropriate commands to perform?
What software can I use to design the user interfaces to capture the data in the computer and how does the device understand the same ?
Kindly let me know of any videos / books / online sites that explain in detail of these simple and basic concepts.
Thanks in advance, Sarita