Page 81 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

TCON Registers
It is Timer control Register.
It is an 8-bit register.

SP (Stack Pointer)
The stack is a portion of RAM Used by the CPU to store data or memory address on temporary basis.
The stack pointer register is used to access the stack known as SP register. The stack pointer register is 8-bits
wide. It can take a value of 00 to FFH. The RAM memory location 08H is the first location used for the stack. When
the 8051 microcontroller is initialized, the SP register contains the value 07H.
If we want to store CPU register data into the stack this is known as PUSH operation and if we are getting the data
from stack back into a CPU register this is known as a POP operation.

DP (Data pointer register)

The data pointer is a 16-bit register used to hold the 16-bit address of data memory. This can also be used as two
8-bit registers namely DPH and DPL. Data Pointer can be used as a single 16-bit register (as DPTR) or two 8-bit
registers (as DPL and DPH).

The 8-bit data pointers are used for accessing internal RAM and SFR. The 16-bit data pointer is used for accessing
external data memory.
The contents of data pointer are programmable using instructions. It is used by the 8051 to access external
memory using the address indicated by DPTR.

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CITS : E & H - Electronics Mechanic - Lesson 34 - 42