Module-5-Introduction-to-Programmable-Logic-PROF.pdf
- 1. Introduction to Programmable Logic Module 5 1 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr. LCST – Logic Circuits and Switching Theory Source: Digital Fundamentals by Floyd, T. 11th Edition
- 2. Introduction Programmable logic requires both hardware and software. Programmable logic devices can be programmed to perform specified logic functions and operations by the manufacturer or by the user. One advantage of programmable logic over fixed-function logic (covered in Module 6) is that the devices use much less board space for an equivalent amount of logic. Another advantage is that, with programmable logic, designs can be readily changed without rewiring or replacing components. 2 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr.
- 3. Introduction Also, a logic design can generally be implemented faster and with less cost with programmable logic than with fixed-function logic. To implement small segments of logic, it may be more efficient to use fixed-function logic. 3 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr. cont’d
- 4. Learning Objectives After completing this module, the learners should be able to: 1. List several types of logic functions of programmable logic and discuss the differences. 2. Discuss the programmable logic design process. 4 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr.
- 5. Programmable Logic Devices (PLDs) Many types of programmable logic are available, ranging from small devices that can replace a few fixed-function devices to complex high-density devices that can replace thousands of fixed- function devices. 5 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr.
- 6. Programmable Logic Devices (PLDs) The SPLD was the original PLD and is still available for small- scale applications. Generally, an SPLD can replace up to ten fixed-function ICs and their interconnections, depending on the type of functions and the specific SPLD. Most SPLDs are in one of two categories: PAL and GAL. 6 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr. cont’d
- 7. Programmable Logic Devices (PLDs) A PAL (programmable array logic) is a device that can be programmed one time. It consists of a programmable array of AND gates and a fixed array of OR gates. 7 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr. cont’d
- 8. Programmable Logic Devices (PLDs) A GAL (generic array logic) is a device that is basically a PAL that can be reprogrammed many times. It consists of a reprogrammable array of AND gates and a fixed array of OR gates with programmable ouputs. 8 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr. cont’d
- 9. Programmable Logic Devices (PLDs) Complex Programmable Logic Device (CPLD) Essentially, the CPLD is a device containing multiple SPLDs and can replace many fixed-function ICs. Each Logic Array Block (LAB) is roughly equivalent to one SPLD. 9 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr. cont’d
- 10. Programmable Logic Devices (PLDs) Complex Programmable Logic Device (CPLD) Generally, CPLDs can be used to implement any of the logic functions discussed earlier, for example, decoders, encoders, multiplexers, demultiplexers, and adders. 10 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr. cont’d
- 11. Programmable Logic Devices (PLDs) An FPGA is generally more complex and has a much higher density than a CPLD, although their applications can sometimes overlap. As mentioned, the SPLD and the CPLD are closely related because the CPLD basically contains a number of SPLDs. The FPGA, however, has a different internal structure (architecture), as illustrated in Figure 1–34. The three basic elements in an FPGA are the logic block, the programmable interconnections, and the input/output (I/O) blocks. 11 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr. cont’d
- 12. Programmable Logic Devices (PLDs) 12 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr. cont’d
- 13. Programmable Logic Devices (PLDs) Large FPGAs can have tens of thousands of logic blocks in addition to memory and other resources. A typical FPGA ball-grid array package is shown in Figure 1–35. These types of packages can have over 1000 input and output pins. 13 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr. cont’d
- 14. The Programming Process An SPLD, CPLD, or FPGA can be thought of as a “blank slate” on which you implement a specified circuit or system design using a certain process. This process requires a software development package installed on a computer to implement a circuit design in the programmable chip. The computer must be interfaced with a development board or programming fixture containing the device. 14 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr.
- 15. The Programming Process 15 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr. cont’d
- 16. The Microcontroller A microcontroller is different than a PLD. The internal circuits of a microcontroller are fixed, and a program (series of instructions) directs the microcontroller operation in order to achieve a specific outcome. The internal circuitry of a PLD is programmed into it, and once programmed, the circuitry performs required operations. Thus, a program determines microcontroller operation, but in a PLD a program determines the logic function. 16 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr.
- 17. The Microcontroller Microcontrollers are generally programmed with either the C language or the BASIC language. A microcontroller is basically a special-purpose small computer. Microcontrollers are generally used for embedded system applications. An embedded system is a system that is designed to perform one or a few dedicated functions within a larger system. By contrast, a general-purpose computer, such as a laptop, is designed to perform a wide range of functions and applications. 17 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr. cont’d
- 18. The Microcontroller Embedded microcontrollers are used in many common applications. The embedded microcontroller is part of a complete system, which may include additional electronics and mechanical parts. For example, a microcontroller in a television set displays the input from the remote unit on the screen and controls the channel selection, audio, and various menu adjustments like brightness and contrast. In an automobile a microcontroller takes engine sensor inputs and controls spark timing and fuel mixture. Other applications include home appliances, thermostats, cell phones, and toys. 18 Module 5 – Introduction to Programmable Logic Prepared by:; fscjr. cont’d
- 19. Mastery Exercises 19 1. List three major categories of programmable logic devices and specify their acronyms. Simple programmable logic device (SPLD), complex programmable logic device (CPLD), and field- programmable gate array (FPGA) 2. How does a CPLD differ from an SPLD? A CPLD is made up of multiple SPLDs. 3. What are the two main functional characteristics of a microcontroller? The microcontroller has fixed internal circuits and its operation is directed by a program. cont’d Module 5 – Introduction to Programmable Logic Prepared by:; fscjr.