Baud Rate Setting in Serial Communication in 8051 Microcontroller 

Yeah they have a lot of good information.

Because timer counts up and triggers the UART on overflow (FFh to 00h transition). -3 (FDh) means timer will overflow in 3 ticks which divides base uart frequency by 3.

timers in 8051 can be configured into 4 modes. 1. Timer 1 mode 0 [13 bit counter] 2. Timer 1 mode 1 [16 bit counter] 3. Timer 1 mode 2 [Auto reload] 4. Timer 0 mode 3 [split timer 0 into two 8 bit counters] [since 8051 has two 16 bit timers/counters

First advantage of using serial port is that no. of pins are saved as only RxD and TxD pins are used for data transmission. Second thing is serial communication is long distance communication.

It depends upon the UART circuitry. In 8051 circuitry it is by default 32. It may vary from controller to controller

No

Because a 8051 core is not fast enough to leverage higher baudrates. 9600kbps generally adapts better to the 8051 processing speed.

TL is not used in 8 bit mode (TH is used to reuse the 16 bit mode overflow circuitry)

To obtain the operating frequency of UART (28, 800 Hz) circuit, the crystal frequency is divided by 32.

These are the data bits

The ans is 3. Subtract it from (FF) hex which comes out to be (FD) hex its 2's complement will be -3 so value taken is negative

@@shrikrishnakolhar9800 sry for that comment if u felt bad ,dnt tk it prsnl .....the comment id for video not on your knowlegde sir.....and thnk u so much for clarification. if u can handle negative comment then u r good to go.

@@shrikrishnakolhar9800 why we are taking this 2 s complement

@@shrikrishnakolhar9800 sir why we are subtracting 3 from FF...and what will happen if we set TH1 with FD..means how will it set the baud rate to 9600

@@darshitgandhi9122 there is no difference between -3 and FD. As shown in the example in video 28800 Hz is divided by 9600 to get TH1 value as -3 or FD hex

Because UART send and receive registers connections are hardwired to the TX and RX pins. You could use regular I/O pins for serial data transfer, but you should have to code your own uart in software (much slower).

there is SBUF register which acts as parallel in serial out shift register for TX and serial in parallel out shift register for RX. While transmission of data the data is first copied into SBUF register which is framed with start and stop bit and it is then serial (one bit at a time) transmitted on TxD pin. Same way at the time of reception the data is received on RxD pin one bit at a time and copied into SBUF register and then taken out in some another register. Every pin has its dedicated role according to the hardware inside the chip.