What is the register structure of PSW in 8051?
The program status word (PSW) register is an 8-bit register, it is also referred to as the flag register the PSW register is 8-bit wide only 6-bit of it are used by the 8051, the two unused bits are user definable flags, four of the flags are called conditional flags, meaning that they indicate some conditions that …
What is PSW in 8051 microcontroller?
The Program Status Word (PSW) contains status bits that reflect the current CPU state. The 8051 variants provide one special function register called PSW with this status information.
How many bits register is PSW?
8-bit
The program status word (PSW) register is an 8-bit register, also known as flag register. It is of 8-bit wide but only 6-bit of it is used. The two unused bits are user-defined flags….8051 Flag Bits and PSW Register.
| CY | PSW.7 | Carry Flag |
|---|---|---|
| OV | PSW.2 | Overflow Flag |
| – | PSW.1 | User definable FLAG |
Is PSW a bit addressable register?
The PSW register is a bit and byte-addressable register. This register reflects the status of the operation that is carried out in the controller.
What do you mean by PSW define each bit?
In 8085 microprocessors, PSW stands for Program Status word. it is a 16-bit word, a combination of contents of the 8-bit flag register and the contents of an 8-bit Accumulator register.
In which bits of the PSW register are user definable in 8051?
The flag register also called as the program status word uses only 6 bits. The two unused bits are user definable flags.
What should be the bits of the register PSW if we want to select register Bank2 of 8051?
7. How are the bits of the register PSW affected if we select Bank2 of 8051? Explanation: Bits of PSW register are CY, AC, F0, RS1, RS0, OV, -, P so for selecting bank2 RS1=1 and RS0=0 which are fourth and third bit of the register respectively.
What is PSW register?
The Program Status Word or PSW is a collection of data 8 bytes (or 64 bits) long, maintained by the operating system. It keeps track of the current state of the system.
Which bits of the PSW are responsible for selection of the register banks?
D4 and D3 bits of the PSW are used to select the desired register bank, since they can be accessed by the bit addressable instructions SETB and CLR. For example, “SETB PSW. 3” will set PSW.
What is the standard form of PSW?
The program status word (PSW) is a register that performs the function of a status register and program counter, and sometimes more. The term is also applied to a copy of the PSW in storage.
Which bits of the PSW are responsible for selection of register banks?
Which bits of the PSW of 8051 are user definable?
The two unused bits are user definable flags. Carry, auxiliary carry, parity and overflow flags are the conditional flags used in it.
What is PSW register in 8051?
PSW (program status word) register The program status word (PSW) register is an 8-bit register. It is also referred to as the flag register. Although the PSW register is 8 bits wide, only 6 bits of it are used by the 8051.
How many bits are in the 8051 PSW?
Although the PSW register is 8 bits wide, only 6 bits of it are used by the 8051. The two unused bits are user-definable flags. Four of the flags are called conditional flags, meaning that they indicate some conditions that result after an instruction is executed.
What is the flag register in the 8051 microprocessor?
Like any other microprocessor, the 8051 has a flag register to indicate arithmetic conditions such as the carry bit. The flag register in the 8051 is called the program status word (PSW) register. In this section we discuss various bits of this register and provide some examples of how it is altered.
What is psw1 in microcontroller?
The Program Status Word (PSW) contains status bits that reflect the current CPU state. The 8051 variants provide one special function register called PSW with this status information. The 251 provides two additional status flags, Z and N, that are available in a second special function register called PSW1.