In what different ways can operations be initiated in the microprocessor
Microprocessor initiated
Internal Operations
Peripheral
Describe the address bus
- Group of 16 bit lines s generally identified as
A0toA15
-Unidirectional data flow from the MPU to the peripheral devices
-Capable of addressing up to 2^16 (64 K) locations
Describe the data bus
- 8 lines of data flow
- Bidirectional
-The 8 data lines enable the MPU to manipulate an 8 bit data ranging from 00H − FFH
-The largest number that can appear on the data bus is 11111111 (25510)
Describe the control bus
-Various single lines that carry synchronization signals
-Not grouped together. They are individual lines which provide pulses for operation control
Describe the microprocessor as a programmable device
The microprocessor is a programmable device.
It can be programmed to perform and operation on data.
This instructions are given to the microprocessor by writing thein the memory
What are the four primary functions of the microprocessor
1 Memory read: Read instructions or data from the memory
2 Memory write: Writes data or instructions from the memory
3 I/O read accepts data from input devices
4 I/O write: Sends data to output devices
Describe what the microprocessor needs to do communicate with peripherals
▶ Identify the peripheral and the memory location with its address
▶ Transfer binary information data or instructions
▶ Provide timing or synchronization signals
Illustrate the intel 8085 bus structure
See slide 33
Describe the control signals sent over the control bus
-It is the MPU which generates these control signals especially when it performs memory read or write operations
-These signals are used to identify the devices with which the MPU is communicating
Describe and illustrate the steps of the memory read operation
To communicate with memory, the MPU places a 16 bit address on the address lines
The addresses are the decoded by an external logic circuit and the memory is identified
The MPU sends a pulse called memory read as the control signal
It is the MPU which generates these control signals especially when it performs memory read or write operations
The pulse activates the memory chip and the contents of this memory are place on the 8 bit data bus and brought into the MPU
*See slide 37 for illustration
Draw the intel 8085 pin and function diagrams
See slide 38
Describe how the address bus pins in the 8085 are divided
The 16 lines(pins) are used for address bus however the lines are divided into two groups A15 − A8 and AD7 − AD0
The lines A15 − A8 are unidirectional while AD7 − AD0 are bi-directional
Describe multiplexing
AD7 − AD0 are used for dual purpose. They serve dual purpose.
They are used as the low-order address bus as well as the data bus.
During the earlier part of the cycle these lines as low as low order address bus.
During the later part of the cycle, these lines are used for data bus.
