All PIC microcontroller family uses a Harvard architecture, which has the program and information accessed from separate memories so the machine has a program memory bus and a data memory bus (more than 8 lines in a usual bus). This improves the bandwidth (data throughput) more traditional von Neumann architecture where program and data are fetched from the equal memory (accesses over the same bus). Separating the program and data memory furthermore allows instructions to be a sized differently than the 8-bit wide data word.
Peripheral Interface Controller also known as PICs, are used in electrical circuits as well as small controllers and controllers in circuits that require a set amount of processing. Peripheral Interface Controllers are used by hobbyists since they are inexpensive, simple to use, and the majority kinds contain flash memory so that they can be a reprogrammed. They are also used by scientists and engineers because of their toughness and flexibility. They can be used in circuits as multifaceted as drive systems for motors and as easy AND gates in a simple circuit.
What is a Peripheral Interface Controller?
Microchip Corporation manufactured a series of Microcontroller chip’s name as “peripheral interface controller” or just called as PIC (also called as a programmable interface controller). Microchip Corporation furthermore provides a trademark for the given name PIC. The term “PIC” is in general used to describe the micro controllers residential by Microchip Corporation. Before we talk about more PIC, you must know the fundamentals about microprocessors and microcontrollers.
Peripheral Interface Controller (PIC) is one of the sophisticated Microcontrollers developed by microchip technologies. These Microcontrollers are extensively used in modern electronics applications. A PIC controller integrates all kinds of advanced interfacing ports and memory modules. These controllers are highly advanced than a regular Microcontroller like INTEL 8051. The first PIC chip announced in 1975 (PIC1650). As like regular Microcontroller, the PIC chip also combines together a microprocessor unit and it’s known as a CPU and is integrated with different types of memory modules (RAM, ROM, EEPROM, etc.), I/O ports, timers/counters, communication ports, etc.
Peripheral Interface Controller Working
PICs are Microcontrollers used in circuits for the procedure, electrical commands. The source PICs were implemented was because they are a cheap way of implementing a controller in a circuit. The cause they are cheaper is because they can be used for several purposes because of their static memory. PICs are used to create complex circuits less complex. One case of why PICs rotate complex circuits into simpler circuits is their capability to replace several AND gates. Various circuits require several AND gates to create processes happen in a specific order. Putting several AND gates onto a circuit board takes up extra space than now putting one PIC on the board.
The dimensions of some of the more superior PICs are the equal size or smaller than a single basic AND gate. This means that if more than one AND gate is used in a circuit the space necessary is as numerous times less when using a PIC than the amount of AND gates that requires to be used. The way PICs work is by primary programming them to do what is desired of them and then put them into a circuit. They then interpret signals sent to them and react the way that they are programmed to react. Some PICs are powerful and sufficient to differentiate between voltage wavelengths while the more basic ones restore simpler components like AND gates
Building Blocks for Implementation
All that is necessary to use PICs are a PIC programming device and fundamental programming skills. The hardware that is essential to program a PIC only cost approximately $50. What is good about the some of the newer PICs is that they approach with USB connectors. This means that particular hardware for programming them is no longer required all that is needed is a computer with a USB port. The cause that simply basic programming skills are needed is because of the numerous different computer languages that can be used.
A few examples of these languages are basic, C, C++, and assembly. The reason that all of these languages can be used to program the similar PIC is because of all the PIC compilers that are accessible. These program compilers can be established online, and mainly about them is open source code so they do not cost anything. The simply extra necessity for choosing the correct PIC is the pin configuration. PICs contain so many different pin configurations and choosing the correct one for the circuit board is a requirement.
The purpose of CPU in PIC is same as a regular Microcontroller CPU. A PIC CPU consists of a number of subunits such as an instruction decoder, ALU, accumulator, control unit, etc. The CPU in PIC usually supports Reduced Instruction Set Computer (RISC) architecture (Reduced Instruction Set Computer (RISC), a kind of microprocessor that focuses on quick and efficient processing of a comparatively small set of instructions. RISC design is based on the principles that mainly of the instructions a computer decodes and executes are easy.
As a result, RISC architecture limits the number of instructions that are built into the Microcontroller, but optimizes each so it can be passed out very quickly (typically within a single clock cycle.). These RISC structures give the following advantages.
- The RISC structure simply has 35 simple instructions as compared to others
- The execution time is similar to most of the instructions (except for very few numbers).
- The execution time necessary is very less (5 million instructions/second (roughly).
The memory in a PIC chip is used to store the data and programs are temporary or permanent. As like usual Microcontrollers, the PIC chip also has a certain quantity of RAM, ROM, EEPROM, other flash memory, etc. ROM memory is used for stable storage. The ROM memory also called as a program memory. A PIC chip has a certain quantity of ROM memory. EEPROM memory is another kind of ROM memory. The contents of the EEPROM changed through run time, and at that time it acted as a RAM memory. But the dissimilarity is after the power goes off, the data remains in this ROM chip.
This is the one of the unique advantages of EEPROM. In the PIC chip the purpose of EPROM is to store the values produced during the runtime.RAM memory is the one of the complex memory modules in a PIC chip. This memory connected with different type of registers (special function registers and general purpose registers) and memory BANK modules (BANK 0, BANK 1, etc.). Formerly the power goes off; the contents of the RAM will be empty. As like usual Microcontrollers, the RAM memory is used to store temporary data and give immediate results.
This is a particular type of memory where READ, WRITE, and ERASE operations can be complete several times. This type of memory was made-up by INTEL Corporation in 1980. A PIC Chip in general contains a certain quantity of flash memory.
Information is stored in a CPU, memory location is called as a register. Registers can be considered as the CPU’s tiny scratch pad, temporarily storing instructions or data. Registers essentially classified into the following.
General Purpose Register (GPR)
General purpose register (or processor register) is a little storage area obtainable on a CPU whose contents can be accessed more quickly than other storage that’s available on PIC. A general purpose register can store both data addresses simultaneously.
Special Function registers (SFR)
These are also a part of RAM memory locations. As compared to GPR, their reason is predetermined during the manufacturing time and cannot be changed by the user. It is simply for special dedicated functions.
Interrupt is a temporary delay in a running program. These delays stop the current implementation for a particular interval. This interval/delay is typically called as an interrupt. When an interrupt apply for arrives into a current execution program, then it stops its regular execution. An interrupt can be performed through external (hardware interrupts) or internally (by using software).
BUS is the communication or data transmission/reception path in a Microcontroller unit. In a usual Microcontroller chip, two types of buses are generally available.
Data buses are used for memory addressing. The purpose of the data bus is interfacing all the circuitry components inside the PIC chip.
Address bus mostly used for memory addressing. The role of the address bus is to transmit the address from the CPU to memory locations.
USART or UART
These ports are used for the transmission (TX) and reception (RX) of the data. These transmissions probable with help of different digital data transceiver modules like RF, IR, Bluetooth, etc. This is the one of the easiest methods to communicate the PIC chip with other devices.
Oscillator unit fundamentally an oscillation/clock generating circuit which is used for providing proper clock pulses to the PIC chip. This clock pulses also helps with the timing and counting applications. PIC chips usually use various types of clock generators. According to the application and the kind of PIC used, the oscillators and its frequencies are may vary. RC (Resistor-Capacitor), LC (Inductor-Capacitor), RLC (Resistor-Inductor-capacitor), crystal oscillators, etc. Are the common oscillators used with A PIC chip.
The whole PIC chip has an area for storing the return addresses. This area or unit called Stack is used in various Peripheral interface controllers. The hardware stack is not available by software. But for the largest part of the controller, it can be simply accessed.
These ports are used for the interfacing different input/output devices and memories. According to the kind of PIC, the number of ports may vary.
Advanced Functioning Blocks
These sections consist of various advanced features of a PIC chip. According to the kind of PIC, these features can vary. Different advanced features in a peripheral interface controller are powered up timer, oscillator start up timer, power on reset, watchdog timer, brownout reset, in circuit debugger, low voltage programming, voltage comparator, CCP modules etc.
Limitations of PIC Architecture
- Peripheral Interface Controller has simply one accumulator.
- Little instruction sets.
- Register banking switch necessary to access RAM of additional devices.
- Operations and registers are not being orthogonal.
- Program memory is not available.
Advantages of PIC Controlled System
The PIC controlled system regularly resides machines that are predictable to run continuously for so many years without any mistake and in some cases recover by themselves if a mistake occurs (with the help of the supporting firmware).
Several of the PIC based embedded system uses an easy pipelined RISC processor for the computation and nearly all of them provide on-chip SRAM for data storage to advance the performance.
A PIC controlled system operates with least power expenditure without sacrificing presentation. Power consumption can be reduced by separately and dynamically controlling numerous power platforms.
Majority of the PIC based systems is memory, expandable and will help in simply adding more and more memory according to the procedure and type of application. In small applications the inherent memory can be used.
Thus, this article discusses about an introduction of the peripheral interface controller and also talking a brief information about the architecture of peripheral interface controller, building blocks for implementation, source of PIC Structure, limitations of PIC architecture and application of the PIC controlling systems. We hope that you have got a better understanding of this concept. Furthermore, any doubts regarding this concept or to implement an electrical and electronics projects, please give your feedback by commenting in the comment section below. Here is a question for you, what is the main function of PIC Microcontroller?