Reset occurs when the RST pin is supplied with a positive pulse in duration of at least 2 machine cycles (24 clock cycles of crystal oscillator). After that, the microcontroller generates an internal reset signal which clears all SFRs, except SBUF registers, Stack Pointer and ports (the state of the first two ports is not […]
All 8051 microcontrollers have 4 input-output (IO) ports each of 8-bits which can be configured as inputs or outputs. The four ports are port 0, port 1, port 2 and port 3. Let’s understand the port structure of 8051 microcontroller for each port. Input/Output Ports in 8051 Microcontroller In order to configure a microcontroller pin
All 8051 microcontrollers have 4 I/O ports each comprising 8 bits which can be configured as inputs or outputs. The four ports are port 0, port 1, port 2 and port 3. Lets understand the functions of ports in 8051 microcontroller. Each port is 8-bit port having 8 pins and has D-type o/p latch for
The 8051 microcontroller is a popular 8-bit microcontroller widely used in embedded systems. Its timing and control unit (TCU) is responsible for generating and controlling the timing signals required for the proper functioning of the microcontroller. Functions Here are the main functions of the 8051 timing and control unit: Clock Generation: The TCU generates the
Microcontroller 8051 has many registers mainly classified into General purpose and Special Function registers. SP, PC and DPTR are the special function registers used in 8051 microcontrollers which work as memory pointer. Let’s see the function of Stack Pointer Data Pointer and Program counter in 8051 Microcontroller one by one. The Stack Pointer (SP) in
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In this article, we will discuss about the concept of stack and stack pointer in 8051 microcontroller. 8051 Stack Pointer The stack is a section of internal RAM used by the CPU to store information temporarily. This information could be data or an address. The CPU needs this storage area since there are only limited
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The 8051 microcontroller is packaged in 40 pin dual in line package (DIP). Out of 40 pins, 16 pins are single function pins and 24 pins may be used for one or two entirely different function. The pin configuration of 8051 microcontroller is as follows. Figure 1: Pin diagram of 8051 Microcontroller Out of 32
Flags are single bit register and used to store the result of certain function after executing instruction. Flags are grouped inside PSW and PCON registers. PSW register in 8051 microcontroller contains math flags and PCON contains general user flags. Math flags are grouped in PSW of microcontroller 8051 and they are Carry(C), Auxiliary Carry (AC),
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The architecture of 8051 microcontroller can be divided into five main sections: the CPU, the program memory, the data memory, the input/output (I/O) ports and the timer and control unit. CPU: The CPU of the 8051 microcontroller is an 8-bit processor that can execute instructions at a clock speed of up to 12 MHz. The
Depending on operation they perform, instruction set in 8051 microcontroller is divided in several groups, such as: Arithmetic Instructions Branch Instructions Data Transfer Instructions Logic Instructions Bit-oriented Instructions Let’s have a look over instructions in ALP first. Instructions in ALP The first part of each instruction, called MNEMONIC refers to the operation an instruction performs
