Embedded systems unit2
- 1. Embedded for Mechatronic systems Unit 2-Processor and Memory Organization Baskaran s Dr.Mahalingam College of Engg & Tech 2019 Baskaran s Embedded for Mechatronic systems
- 2. Bus Organization Bus Bus is a group of conducting wires which carries information, all the peripherals are connected to microprocessor through Bus. Types: Address bus Data bus Control bus Baskaran s Embedded for Mechatronic systems
- 3. Bus Organization Functions of Buses in Computers 1. Data sharing - All types of buses found in a computer transfer data between the computer peripherals connected to it. The buses transfer or send data either in the serial or parallel method of data transfer. This allows for the exchange of 1, 2, 4 or even 8 bytes of data at a time. (A byte is a group of 8 bits). Buses are classified depending on how many bits they can move at the same time, which means that we have 8-bit, 16-bit, 32-bit or even 64-bit buses. 2. Addressing - A bus has address lines, which match those of the processor. This allows data to be sent to or from specific memory locations. Baskaran s Embedded for Mechatronic systems
- 4. Bus Organization Functions of Buses in Computers 3. Power - A bus supplies power to various peripherals con- nected to it. 4. Timing - The bus provides a system clock signal to synchro- nize the peripherals attached to it with the rest of the system. Baskaran s Embedded for Mechatronic systems
- 5. Bus Organization Figure: Types of Buses Baskaran s Embedded for Mechatronic systems
- 6. Types of buses Address bus It is a group of conducting wires which carries address only.Address bus is unidirectional because data flow in one di- rection, from microprocessor to memory or from microprocessor to Input/output devices Baskaran s Embedded for Mechatronic systems
- 7. Types of buses Data bus It is a group of conducting wires which carries Data only.Data bus is bidirectional because data flow in both directions, from microprocessor to memory or Input/Output devices and from memory or Input/Output devices to microprocessor Baskaran s Embedded for Mechatronic systems
- 8. Types of buses Control bus It is a group of conducting wires, which is used to generate timing and control signals to control all the associated peripherals, microprocessor uses control bus to process data, that is what to do with selected memory location. Some control signals are: 1.Memory read 2.Memory write 3.I/O read 4.I/O Write Baskaran s Embedded for Mechatronic systems
- 9. Embedded Memory Devices Memory A memory is just like a human brain. It is used to store data and instruction The memory is divided into large number of small parts. Each part is called a cell. Each location or cell has a unique address which varies from zero to memory size minus one. For example if computer has 64k words, then this memory unit has 64 * 1024 = 65536 memory location. The address of these locations varies from 0 to 65535. Baskaran s Embedded for Mechatronic systems
- 10. Memory Types Memory is primarily of two types; Internal Memory cache memory and primary/main memory External Memory magnetic disk / optical disk etc. Apart from that Figure: Common memory types in embedded systems Baskaran s Embedded for Mechatronic systems
- 11. Types of RAM SRAM Vs DRAM The RAM family includes two important memory devices: static RAM (SRAM) and dynamic RAM (DRAM). The pri- mary difference between them is the lifetime of the data they store. SRAM retains its contents as long as electrical power is applied to the chip. If the power is turned off or lost temporarily, its contents will be lost forever. DRAM, on the other hand, has an extremely short data lifetime-typically about four milliseconds. This is true even when power is applied constantly. Generally, SRAM is used only where access speed is ex- tremely important. A lower cost-per-byte makes DRAM at- tractive whenever large amounts of RAM are required. For smaller data SRAM (a few kilobytes) is good choice and for handling larger data DRAM(Megabytes) is preferred. Baskaran s Embedded for Mechatronic systems
- 12. Types of ROM PROM PROM is read-only memory that can be modified only once by a user. The user buys a blank PROM and enters the desired con- tents using a PROM program. Inside the PROM chip, there are small fuses which are burnt open during programming. It can be programmed only once and is not erasable Baskaran s Embedded for Mechatronic systems
- 13. Types of ROM EPROM EPROM can be erased by exposing it to ultra-violet light for a duration of up to 40 minutes. Usually, an EPROM eraser achieves this function. During programming, an electrical charge is trapped in an insulated gate region. The charge is retained for more than 10 years because the charge has no leakage path. For erasing this charge, ultra-violet light is passed through a quartz crystal window (lid). Baskaran s Embedded for Mechatronic systems
- 14. Types of ROM MROM The very first ROMs were hard-wired devices that contained a pre-programmed set of data or instructions. These kind of ROMs are known as masked ROMs, which are inexpensive Baskaran s Embedded for Mechatronic systems
- 15. Types of ROM EEPROM EEPROM (pronounce as ”E-E-PROM”) stands for Electri- cally Erasable Programmable Read-Only Memory. It is a non-volatile ROM chip which used for storing a small amount of data in computers or some other electronic de- vices. Through EEPROM, an individual byte of data can erase and reprogrammed entirety, not selectively by the electrical volt- age. Baskaran s Embedded for Mechatronic systems
- 16. Types of ROM Flash Flash memory, also known as flash storage, is a type of nonvolatile memory. Flash memory is widely used for storage and data trans- fer in consumer devices, enterprise systems and industrial applications. Flash memory retains data for an extended period of time, regardless of whether a flash-equipped device is powered on or off. Flash memory is a type of electrically erasable pro- grammable read-only memory (EEPROM) Baskaran s Embedded for Mechatronic systems
- 17. Types of ROM NVRAM NVRAM is an acronym for Non-Volatile Random Access Memory. NVRAM is a type of Random Access Memory (RAM) that retains its information when power is turned off. The NVRAM is a small 24 pin DIP (Dual Inline Package) integrated circuit chip and is thus able to obtain the power needed to keep it running from the CMOS battery installed in your motherboard. It keeps track of various system parameters such as serial number, Ethernet MAC (Media Access Control) address, HOSTID, date of manufacture, etc. NVRAM is therefore a type of non-volatile memory that of- fers random access. Baskaran s Embedded for Mechatronic systems
- 18. RISC Vs CISC RISC RISC: Reduce the cycles per instruction at the cost of the number of instructions per program Simpler instruction, hence simple instruction decoding. Instruction come under size of one word. Instruction take single clock cycle to get executed. More number of general purpose register. Simple Addressing Modes. Less Data types. Pipeling can be achieved Baskaran s Embedded for Mechatronic systems
- 19. CISC CISC Complex instruction, hence complex instruction decoding. Instruction are larger than one word size. Instruction may take more than single clock cycle to get executed. Less number of general purpose register as operation get performed in memory itself. Complex Addressing Modes. More Data types. Baskaran s Embedded for Mechatronic systems
- 20. RISC Vs CISC Baskaran s Embedded for Mechatronic systems
- 21. 8051 Architecture Baskaran s Embedded for Mechatronic systems
- 22. 8051 8051 microcontroller is 8 bit microcontroller designed by In- tel in 1981 It is built with 40 pins DIP (dual inline package). It has 4kb of ROM storage and 128 bytes of RAM storage, 2 16 bit timers It consists of are four parallel 8 bit ports, which are pro- grammable as well as addressable as per the requirement An on-chip crystal oscillator is integrated in the microcon- troller having crystal frequency of 12 MHz Baskaran s Embedded for Mechatronic systems
- 23. Interrupts As its name suggests, Interrupt is a subroutine call that interrupts of the microcontrollers main operations or work and causes it to execute any other program The feature of Interrupt is very useful as it helps in case of emergency operations An Interrupts gives us a mechanism to put on hold the ongoing operations, execute a subroutine and then again resumes to another type of operations Baskaran s Embedded for Mechatronic systems
- 24. Oscillator Oscillator Microcontroller requires Clock pulses for its operation. An elec- tronic circuit that is used to generate an electrical signal of pre- cise frequency by utilizing the vibrating crystal’s mechanical res- onance made of piezoelectric material. There are different types of piezoelectric resonators, but typically, quartz crystal is used in these types of oscillators. Hence, these oscillator electronic cir- cuits are named as crystal oscillators. Baskaran s Embedded for Mechatronic systems
- 25. Oscillator Baskaran s Embedded for Mechatronic systems
- 26. Timer Timer The timer is an important application in Embedded sys- tems,it maintains the timing of an operation in sync with a system clock or an external clock. The timer has so many applications such as measure time generating delays, they can also be used for generating baud rates TIMER/COUNTER is a software designed to count the time interval between events Timer register is incremented for every machine cycle, whereas counter register gets incremented by measuring pulses Baskaran s Embedded for Mechatronic systems
- 27. Cycles Baskaran s Embedded for Mechatronic systems
- 28. Clock cycle Clock cycle The speed of a computer processor, or CPU, is determined by the clock cycle, It is the amount of time between two pulses of an oscillator The higher number of pulses per second, the faster the computer processor will be able to process information The clock speed is measured in Hz, typically either megahertz (MHz) or gigahertz (GHz). For example, a 4GHz processor performs 4,000,000,000 clock cycles per second. Baskaran s Embedded for Mechatronic systems
- 29. Machine cycle Machine cycle The steps performed by the computer processor for each ma- chine language instruction received. The machine cycle is a 4 process cycle that includes reading and interpreting the machine language, executing the code and then storing that code. Baskaran s Embedded for Mechatronic systems
- 30. Instruction cycle Instruction cycle 1.Read an Instruction 2.Decode the instruction 3.Find the address of operand 4.retrieve an operand 5.Perform desired operation 6.find the address of destination 7.store the result into the destination Baskaran s Embedded for Mechatronic systems
- 31. Opcode and operand Baskaran s Embedded for Mechatronic systems
- 32. Opcode and operand Opcode Opcode is the first part of an instruction which tells the computer what function to perform. Every computer has an operation code or opcode for each of its functions. Operand Operand is the second part of the instruction, which tells the computer where to find or store the data or instructions Baskaran s Embedded for Mechatronic systems
- 33. ARM Microcontroller Architecture Baskaran s Embedded for Mechatronic systems
- 34. PIC Microcontroller Architecture Baskaran s Embedded for Mechatronic systems
- 35. Memory organization Baskaran s Embedded for Mechatronic systems
- 36. Memory organization Baskaran s Embedded for Mechatronic systems
- 37. DMA Direct memory access DMA stands for ”Direct Memory Access” and is a method of transferring data from the computer’s RAM to another part of the computer without processing it using the CPU. In order for devices to use direct memory access, they must be assigned to a DMA channel. Each type of port on a computer has a set of DMA channels that can be assigned to each connected device. For example, a sound card may need to access data stored in the computer’s RAM, but since it can process the data itself, it may use DMA to bypass the CPU. Video cards that support DMA can also access the system memory and pro- cess graphics without needing the CPU. Baskaran s Embedded for Mechatronic systems
- 38. DMA Baskaran s Embedded for Mechatronic systems
- 39. Co processor Co processor A coprocessor is a computer processor used to supplement the functions of the primary processor (the CPU). Operations performed by the coprocessor may be floating point arithmetic, graphics, signal processing, string processing, cryptography or I/O interfacing with peripheral devices. By offloading processor- intensive tasks from the main processor, coprocessors can ac- celerate system performance. Coprocessors allow a line of com- puters to be customized, so that customers who do not need the extra performance do not need to pay for it. Baskaran s Embedded for Mechatronic systems
- 40. Hardware acceleration Hardware acceleration Hardware acceleration is a technique in which a computer’s hardware is forced to perform faster than the standard computing architecture of a normal central processing unit (CPU). It is used with heavy computing tasks and opera- tions, like graphics or video processing. Hardware acceleration is forced and controlled by the pro- gram or software that requests extra computing power. For example, Mozilla Firefox supports and can initiate hardware acceleration for websites that are media-rich or have high definition (HD) graphics. A hardware accelerator is a device that implements hard- ware acceleration and includes modern graphic and video cards. Baskaran s Embedded for Mechatronic systems
- 41. Pipe lining Pipe lining pipeline is a set of data processing elements connected in series, where the output of one element is the input of the next one. The elements of a pipeline are often executed in parallel or in time-sliced fashion. Some amount of buffer storage is often inserted between elements. Types Instruction pipe-lining, Arithmetic pipe-lining Baskaran s Embedded for Mechatronic systems
- 42. Positioning figure demo Baskaran s Embedded for Mechatronic systems
- 43. minipage pipeline is a set of data process- ing elements connected in se- ries, where the output of one el- ement is the input of the next one. The elements of a pipeline are often executed in parallel or in time-sliced fashion. Some amount of buffer storage is of- ten inserted between elements Baskaran s Embedded for Mechatronic systems