Microprocessor and Assembly Language Lect 1

1. Microprocessor and Assembly LanguageLect 1 Prepared by : Ustaz: Alzubair Hassan Abdallah

2. What is a microprocessor? • • A processor is built from a large number of integrated circuits. • • A microprocessor is a processor packaged as a single Ic(chip). • • A microcomputer is a computer that uses a microprocessor as its CPU. • • 8-bit, 16-bit, 32-bit microprocessor: refers to number of bits manipulated in one operation. • • It requires external memory to execute programs. • • It cannot directly interface to I/O devices, peripheral • chips are needed.

3. What is a Microcontroller? • A microcontroller is a computer implemented on asingle chip. • Everything a microprocessor has plus (for example): – memory – timer – AD and DA converters(Analog-to-digital converter) – memory controller – parallel and serial ports • We use the Motorola 68HC11, 8-bit microcontroller. • Microcontrollers are used mainly for dedicated applications in embedded systems (appliances,mechanical/electrical control).

4. Memory • • Memory is organized as a number of locations each of which can hold the same size data value (usually a byte). Often consecutive bytes form words (2 bytes),double words (4 bytes) etc. • • Each location has a unique address. A 16-bit address allows for 65,636 (64K) memory locations. • • Don't confuse the address space of the computer (the number of unique addresses) with the amount of actual memory. • • A transfer of data from memory is a read. A transfer of data to memory is a write.

5. Memory Types • Semiconductor memory • Random-access memory (RAM): same amount of time is required to access any location on the same chip • Read-only memory (ROM): can only be read but not written by the processor • Random-access memory • - Dynamic random-access memory (DRAM): periodic refresh is required to maintain the contents of a DRAM chip • - Static random-access memory (SRAM): no periodic refresh is required • Read-only memory • - Mask-programmed read-only memory (MROM): programmed when being manufactured • - Programmable read-only memory (PROM): the memory chip can be programmed by the end user

6. ComputerArchitecture : • The basic operational design of a computer system is called its architecture . • John Von Neumann, a pioneer in computer design, is given credit for the architecture of most computers in use today . • For example, the 80x86 family uses the Von Neumann architecture (VNA) or Princeton architecture

7. What is a Computer? • Central Processing Unit (CPU) • Executes the programs • Primary Memory • Stores programs and data • Input/Output Devices • Allow CPU to communicate with external hardware • System Bus • Connects everything together • Address, Data, Control signals

8. Memory I/O Processor Data Bus Address Bus Control Bus What is computer :

10. The System Bus • The system bus connects the various components of a VNA machine. • The 80x86 family has three major busses: the address bus, the data bus, and the control bus. A bus is a collection of wires on which electrical signals pass between components in the system. • These busses vary from processor to processor. However, each bus carries comparable information on all processors; e.g., the data bus may have a different implementation on the 80386 than on the 8088, but both carry data between the processor, I/O, and memory

11. The Data Bus • The 80x86 processors use the data bus to shuffle data between the various components in a computer system. The size of this bus varies widely in the 80x86 family. Indeed, this bus defines the “size” of the processor

12. Evolution micro-processor The digital circuits and systems can be broken into: • Combinational Circuits • Sequential Circuits

13. Internal Architecture • The architecture of 8086 provides a number of improvements over 8085 architecture. It supports a 16-bit ALU, a set of 16-bit registers and provides segmented memory addressing capability, a rich instruction set, powerful interrupt structure, fetched instruction queue for overlapped fetching and execution etc. • The internal block diagram, shown in Figure 2.1, describes the overall organization of different units inside the chip.

15. Pin descriptions of 8086 • The microprocessor 8086 is a 16-bit CPU available in three clock rates, i.e. 5, 8 and 10 MHz, packaged in a 40 pin CERDIP or plastic package. The 8086 operates in single processor or multiprocessor configurations to achieve high performance. The pin configuration is shown in Figure 2.4. • Some of the pins serve a particular function in minimum mode (single processor mode) and others function in maximum mod(multiprocessor mode) configuration. • The 8086 signals can be categorised in three groups. The first are the signals having common functions in minimum as well as maximum mode, the second are the signals which have special functions for minimum mode and the third are the signals having special functions for maximum mode.

17. The End Questions?