MICROPROCESSOR AND MICROCONTROLLER

Detailed explanation-1: -It is an 8-bit register in which the lower 4 bits are set aside for Timer 0 and the upper four bits for Timers. In each case, the lower 2 bits are used to set the timer mode in advance and the upper 2 bits are used to specify the location.

Detailed explanation-2: -TMOD is an 8-bit register used to set timer mode of timer0 and timer1.

Detailed explanation-3: -These 8-bit registers are used for the storing the memory addresses that can be used to access internal and external data/code. The stack pointer (SP) in 8051 is an 8-bit register. The main purpose of SP is to access the stack. As it has 8-bits it can take values in the range 00 H to FF H.

Detailed explanation-4: -8051 Timer Mode Control (TMOD) Special Function Register. Gate–OR gate enable bit which controls RUN/STOP of timer 1. Set to 1 by program to enable timer to run if bit TR1 in TCON is set and signal on external interrupt INT1 is high. Cleared to 0 by program to enable time to run if bit TR1 is set.

Detailed explanation-5: -The 8051 contains two 16-bit registers: the program counter (PC) and the data pointer (DPTR). Each is used to hold the address of a byte in memory. Program instruction bytes are fetched from locations in memory that are addressed by the PC.