Why is the microprocessor important

Research and evaluation of existing configurable microcontrollers

Table of Contents

1 How long have microcontrollers been around?

2 What is a microcontroller

3 Why do we need microcontrollers

4 Structure of common microcontroller processors
4.1 General structure
4.2 Memory in a microcontroller
4.3 The I / O ports
4.4 Problems with today's SoC

5 The transition in detail

6 Tensilicas Xtensa processor
6.1 General
6.2 Basic idea and implementation .8 6.3 Architecture
6.4 Structure
6.5 Example for GSM audio codec
6.6 Example for MPEG 4 Codec

7 Triscend
7.1 General
7.2 Basic idea and realization
7.3 architecture
7.4 Structure

8 Conclusion - differences

9 Bibliography

1. How long have microcontrollers been around?

The microcontroller was born in the mid-1970s; it was a complete small computer on a chip that took over the control and regulation tasks.

2. What is a microcontroller?

Defn .: A microcontroller is a complex system consisting of the CPU (processing unit / microprocessor), the program memory (Flash or EPROM), the main memory (RAM) and the input and output units on a chip. These modules are integrated in many devices as "mini-PCs" and control, for example: printers, heaters, microwaves, alarm clocks, coffee machines, etc.

Microcontrollers are, so to speak, complete computers on a chip (SOC - System on Chip). They are used where processor power is not so important, but compact design, small size, low energy consumption and a low price.

The goal is to solve control and communication tasks with as few modules as possible.

In order to make differences between the microcontrollers clear, they are also divided into so-called microcontroller families. The microcontrollers of a family can have the same processor core, but different memories and input and output interfaces.

A microcontroller is a device that integrates a number of microprocessor components on a chip.

A microcontroller thus combines the following components on one and the same chip:

- the CPU core
- memory (both ROM and RAM)
- Several parallel digital input and output ports

3. What do we need microcontrollers for?

Microcontrollers regulate and control the processes in almost all modern electrical devices. Even if you often do not see them or you suspect them to be in the devices, their process or functionality is usually controlled by one or more microcontrollers. Even in simple devices, such as coffee machines, there are microcontrollers that determine the sequence, timing and behavior.

4. Structure of common microcontroller processors:

4.1 General structure:

Figure not included in this excerpt

Fig. 1: Structure of a microcontroller

Most microcontrollers also combine other devices, such as:

- A timer module, which allows the µC to complete tasks at certain time intervals
- A serial I / O port that allows data to flow between the µC and other devices, such as a PC or another µC
- An ADC which allows the µC to allow analog input data for processing

The following figure shows a typical microcontroller and the various sub-units that are integrated on the microcontroller chip:

Figure not included in this excerpt

Figure 2: Components of a typical microcontroller

4.2 Memory in a microcontroller:

The amount of memory in a microcontroller varies between different microcontrollers. Some have no built-in memory at all (e.g. Hitachi 6503). Most modern microcontrollers, however, have built-in memory. The memory is divided into ROM and RAM, with mostly more ROM than RAM.

ROM: Read-only memory (cannot be erased)

RAM: Random Access Memory

Figure not included in this excerpt

Fig. 3: ROM memory in the microcontroller

The typical amount of ROM memory varies between 512 bytes and 4096 bytes. Except for some 16 bit microcontrollers like the Hitachi H8 / 3048 which has up to 128 KByte ROM memory.

ROM memory is used to store the program code. The ROM memory can either be a ROM, EPROM or EEPROM.

Figure not included in this excerpt

Fig. 4: RAM memory in the microcontroller

The size of the RAM memory is usually a bit smaller, between 25 bytes and 4 KBytes.

RAM memory is used for data storage and stack management tasks. It is also used for register stacks.

4.3 The I / O ports:

Figure not included in this excerpt

Figure 5: I / O ports in the microcontroller

The digital I / O ports are the tools with which the microcontroller communicates with its environment, i.e. its interfaces.

With a few exceptions, digital I / O ports tend to be 8 bits (1 byte) wide and can be configured as input or output bits.

The number of I / O ports varies depending on the size of the microcontroller.

Some 8 bit microcontrollers have only a few (4 bits) and other 16 bit microcontrollers have up to 78 bits of I / O.

4.4 Problems with today's SoC:

In the typical SoC architecture, a number of RTL subsystems (Register Transfer Level) handle the data processing and the embedded processor controls the data path. The RTL subsystems are connected to the processor via the system bus and communicate with it via an interrupt structure. If a subsystem has finished processing the data, it interrupts the processor and waits to be restarted. The processor receives this interrupt, retains its entire context, determines which subsystem caused the interrupt, processes the interrupt, clears it, restores the entire context and returns to its application.


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