Microprocessor Bus and Memory Types: Essential Functions
What is the Role of the Address Bus?
The address bus is a totally independent channel from the microprocessor to the data bus, which contains the memory address of the data in transit. It consists of a set of power lines needed to establish a directional memory capacity. The addressable memory capacity depends on the number of bits that make up the address bus, with 2n (two raised to the n) representing the maximum bytes of the memory bank that can be addressed using *n* lines.
What Does the Data Bus Do?
The data bus is a digital system that transfers data between components of a computer or between computers. It is formed by wires or tracks on a printed circuit, devices such as resistors and capacitors, as well as integrated circuits.
What is the Role of the Control Bus?
The control bus governs the use and access to the data lines and addresses. Since these lines are shared by all components, certain mechanisms must be provided to control their use. The control signals transmit both orders and timing information between the modules. It prevents collisions of information on the system.
What Sequence is Followed for a Memory Read?
- The address bus provides the address of the location in memory.
- The control bus sends a read signal.
- Data is transferred from memory to the CPU.
What Sequence is Followed for a Memory Write?
- The address bus provides the address of the memory location.
- The control bus sends a write signal.
- Data is transferred *through* the data bus.
What is the Sequence for a Write to a Port?
The bus selects the port, and addresses are transferred *through* the data bus.
What is the Basic Structure of a CMOS Field Effect?
When the input is 0, the pMOS transistor is in a conducting state. When connected to its power source (1), the value 1 propagates to the drain and, therefore, to the logic gate output. The nMOS transistor, however, is in a non-conducting state.
What Does Random Access Memory Mean?
It means that any location can be accessed at any time.
Does the Concept Apply to RAM, ROM, or Both?
If applied to both.
Draw the Structure of the FAMOS Memory Cell.
(Note: A drawing cannot be provided in text-based HTML. The description is that it is erased with ultraviolet light.)
Why is it Called a Floating Gate?
The FAMOS is a floating gate transistor; a zero is saved.
What are Read-Only Memories and Programmable Memories Based on Fuses Called?
ROM and PROM.
If a Report Shows All Fuses are Closed, What Value is Stored (1 or 0)? Is the Final Memory Reading in Hexadecimal FF or 00?
The value stored will be 1. The final reading will be FF.
Describe the Characteristics of EPROMs.
EPROMs are erased with ultraviolet light.
What are the Characteristics of EEPROMs and the Difference with Flash Memory?
EEPROMs store data cell by cell, while flash memory stores data in blocks.
What is the Function of the Address Decoder Block in the Diagram?
It converts a binary logic input to unique outputs.
What is the Role of the CE and OE Inputs in the Same Diagram?
OE (Output Enable) controls the high impedance state of the device’s output terminals.
What is a Four-Input and Output Decoder?
A decoder is a device that accepts a digital input and activates a binary encoded output. This device has multiple outputs, and the one that is activated is set by the code applied to the input. With an n-bit code, 2n possible combinations can be found. For example, with 3 bits (3 entries), there will be 23 = 8 possible combinations. A particular combination will activate only one output.
What is the Circuit of a Differentiator?
This circuit is used to detect rising and falling edges of a signal, causing greater differentiation at the input and output sides of the signal. That is where the variation with time (t) becomes more noticeable. These areas of the signal correspond to the high frequencies, while the flat areas are composed of lower frequencies.
What is the Basic Circuitry of a RAM Memory Cell?
a) FAMOS
b) Bipolar transistor arrangement
c) Capacitor and CMOS transistor
d) None of the above
What are EU and BIU?
EU: Execution Unit
BIU: Bus Interface Unit
What are the General Data Registers?
Temporary registers.
What are the Components of the 8086 EU?
Arithmetic Logic Unit and flags.
What are the Segment Registers of the EIU?
DS, DCS, and CS.
What is a Fetch Cycle?
When information is collected from memory, it works like a memory read.
What are the Parts of a Machine Instruction?
The instruction is placed in the ALU. Memory unit registers are stored in the ALU.