8051 FLAG BITS AND PSW REGISTER
The program status word (PSW) register is also known as the flag register.
flag register is an 8 bit register. Only 6 bits are used.
- CY (carry).
- AC (auxiliary carry).
- P (parity).
- OV (overflow).
The PSW3 and PSW4 are designed as RS0 and RS1, and are used to change the bank And left two bits are user-definable.
CY PSW.7 Carry flag (Carry out from the D7 bit)
AC PSW.6 Auxiliary carry flag (A carry from D3 to D4)
— PSW.5 Available to the user for general purpose
RS1 PSW.4 Register Bank selector bit 1.
RS0 PSW.3 Register Bank selector bit 0.
OV PSW.2 Overflow flag.
— PSW.1 User definable bit.
P PSW.0 Parity flag. Set/cleared by hardware each instruction cycle to indicate an
odd/even number of 1 bits in the accumulator.
The Intel 8051 microcontroller is among one of the most popular general purpose microcontrollers in use today. The success of the Intel 8051 spawned a number of clones which are collectively referred to as the MCS-51 family of microcontrollers, which includes chips from vendors such as Atmel, Philips, Infineon, and Texas Instruments.
- 1947 Invention of Transistors.
- 1959 Invention of Integrated Circuits.
- 1971 Invention of Microprocessor.
- 1976 Invention of Microcontroller.
Today, over 50 companies produce variations of the 8051. 8051 cores are available for implementations in Field Programmable Gate Arrays (FPGA) or Application Specific Integrated Circuits (ASIC). The 8051 was developed by Intel but other manufacturers (e.g., Siemens, Philips, Atmel, etc.) are second sources of this family of devices.
- Lectures 16
- Quizzes 0
- Duration 10 hours
- Skill level All levels
- Language English
- Students 51
- Certificate No
- Assessments Self