Basic electronics fundamentals – V

The different types of ADC are successive approximation ADC, counter type ADC flash type ADC, integrator converters and voltage to-frequency converters.

Stack is a sequence of RAM memory locations defined by the programmer.

The program counter keeps track of program execution. To execute a program the starting address of the program is loaded in program. The PC sends out an address to fetch a byte of instruction from memory and increments its content automatically.

The timing and control unit synchronizes all the microprocessor operations with clock and generates control signals necessary for communication between the microprocessor and peripherals.

A device which contains the microprocessor with integrated peripherals like memory, serial ports, parallel ports, timer/counter, interrupt controller, data acquisition interfaces like ADC,DAC is called micro controller.

The internal devices of a DAC are R/2R resistive network, an internal latch and current to voltage converting amplifier.

The time taken by the DAC to convert a given digital data to corresponding analog signal is called conversion time.

The features are
• single supply +5 volt operation using HMOS technology.
• 4096 bytes program memory on chip (not on 8031)
• 128 data memory on chip.
• Four register banks.
• Two multiple mode, 16-bit timer/counter.
• Extensive Boolean processing capabilities.
• 64 KB external RAM size
• 32 bidirectional individually addressable I/O lines.
• 8 bit CPU optimized for control applications.

The interrupts are:
Vector address
• External interrupt 0
• Timer interrupt 0
• External interrupt 1
• Timer Interrupt 1
• Serial Interrupt, Receive interrupt, Transmit interrupt

Direct addressing
• Register addressing
• Register indirect addressing.
• Implicit addressing
• Immediate addressing
• Index addressing
• Bit addressing