Introduction to Microservice Architecture Using SpringBoot - Part 1

 

1. What is PIC microcontroller in embedded system?

PIC Microcontroller is the very smallest microcontroller in the world that can be designed to carry out a huge range of tasks. These microcontrollers are in electronic devices such as phones, computer, and Embedded Operating System etc. Also, the features of these microcontrollers are RAM, CCP, SSP, LCD, and ICSP, etc. PIC microcontroller can be used in different applications such as audio accessories, peripherals, and video games, etc.

PIC Microcontroller Advantages

1. Interfacing of an analog device is easy without extra circuitry.
2. When compared to other microcontrollers, power consumption is very low, and programming is very easy.
3.  It is consistent and faulty of PIC percentage is very low. Using RISC architecture the performance is high-speed.

2. What are the PIC 18 family device?

Microchip Technology PIC16(L)F18425/45 Low Pin Count MCUs are designed to implement extreme Low- Power (XLP) technology for general purpose and low- power applications.

These PIC16(L)F18425/45 MCUs combine intelligent analogy, communication peripherals, and Core Independent Peripherals (CIPs) with XLP technology for optimum low power operation. The

PIC16(L)F18425/45 MCUs feature a 12-bit Analog-to- Digital Converter with Computation (ADC2), Memory Access Partitioning (MAP), Device Information Area (DIA), and Peripheral Pin Select (PPS). These MCUs have up to 28KB program flash memory, up to 2KB data SRAM memory, and 256B data EEPROM.

The PIC16(L)F18425/45 MCUs have multiple digital peripherals including four Configurable Logic Cells (CLCs), two Complementary Waveform Generators (CWGs), and Capture/Compare/PWM (CCP) modules. The analog peripherals include Zero-Cross Detect (ZCD), temperature sensor circuit, Digital-to-Analog Converter (DAC), and Fixed Voltage Reference (FVR) module.

3. What are the Peripheral Features of PIC16F873

Peripheral Features:

1. Timer0: 8-bit timer/counter with 8-bit prescaler

2. Timer1: 16-bit timer/counter with prescaler, can be incremented during SLEEP via external crystal/clock

3. Timer2: 8-bit timer/counter with 8-bit period register, prescaler and postscaler

4. Two Capture, Compare, PWM modules-Capture is 16-bit, max. resolution is 12.5 ns-Compare is

 16-bit, max. resolution is 200 ns-PWM max. resolution is 10-bit

5. 10-bit multi-channel Analog-to-Digital converter 6. Synchronous Serial Port (SSP) with SPI (Master mode) and 12CP?(Master/Slave) Universal Synchronous Asynchronous Receiver Transmitter (USART/SCI) with 9-bit address detection

7. Parallel Slave Port (PSP) 8-bits wide, with external RD, WR and CS controls (40/44-pin only)

8. Brown-out detection circuitry for Brown-out Reset (BOR)

4. Explain the Architecture of PIC Microcontroller

The architecture of this microcontroller consists of CPU, I/O ports, interrupts, oscillator, timers/counters, A/D converter, memory organization, serial communication, and CCP module, etc.

1. I/O Ports: PIC microcontroller consists of five ports such as Port A, Port B, Port C, Port D and Port E. Port A: It is a 16-bit port that can be mainly used for input and output port based on the status of the TRISA register. Port B: This is an 8-bit port that can be used as input and output. Port C: An 8-bit port and the input or output operation is decided by the status of the TRISC register. Port D: An 8-bit port that acts as a slave port for connection to the ARM Microcontroller. Port E: It is a 3-bit port which serves the additional function of the control signals to the analog into a digital converter.

2. Memory Organization: This microcontroller architecture consists of Random Access Memory, Read Only Memory and STACK.

3. Random Access Memory: Random Access Memory is an unstable memory that is used to store the data temporarily in registers. As well as, it is classified into two banks, each bank consists of a number of registers. Also, these registers are divided into two types. They are Special Function Register and General Purpose Register.

4. Read Only Memory: It is a stable memory that is used to store the data permanently. The ROM is also called as a program memory, where the user will write a program and save it permanently and finally the program is executed by the CPU.

5. STACK: The process of a stack is when an interrupt occurs, the PIC microcontroller has to execute the interrupt and existing process address. That is being executed is stored in the stack. After completing the execution of the interrupt, microcontroller calls the process with help of address, that is stored in the stack and get executes the process.

6. Timers/Counters: Timers are mainly used for generating accuracy actions. Although, it has four- timer/counters where the one 8-bit timer and the remaining timers have the choice to select 8 or 16-bit mode.

7. Oscillators: Generally, oscillators are used to generating timing. It consists of an external oscillator such as RC and crystal oscillators. In RC oscillator, the value of capacitor and resistor that is used to determine the clock frequency. The range of clock frequency is 30 KHz to 4MHz.

8. Interrupts: It consists of 20 internal interrupts and three external interrupts, which is associated with different peripherals such as ADC, USART, and Timers etc.

9. CCP module: Generally, CCP stands for Capture/ Compare/ PWM. CCP module works in three modes such as Capture mode, Compare mode and PWM mode.

5.What are the salient features of PIC Microcontroller?

SALIENT FEATURES

1. Speed: When operated at its maximum clock rate a PIC executes most of its instructions in 0.2 us or five instructions per microsecond.

2. Instruction set Simplicity: The instruction set is so simple that it consists of only just 35 instructions

3. Integration of operational features: Power-on-reset (POR) and brown-out protection ensure that the chip operates only when the supply voltage is within specifications. A watch dog timer resets the PIC if the chip malfunctions or deviates from its normal operation at any time.

4. Programmable timer options: Three timers can characterize inputs, control outputs and provide internal timing for the program execution.

5. Interrupt control: Up to 12 independent interrupt sources can control when the CPU deal with each source.

6. Powerful output pin control: A single instruction can select and drive a single output pin high or low in its 0.2 us instruction execution time. The PIC can drive a load of up to 25μA.

7.1/0 port expansion: With the help of built in serial peripheral interface the number of 1/0 ports can be expanded. EPROM/DIP/ROM options are provided.

6. Explain Memory organization of PIC Microcontroller?

Memory organization: The memory module of the PIC controller has three memory blocks. a) Program memory b) Data memory and c) Stack a) Program Memory:

The PIC 16F8XX has 4k x14 program memory space (0000H-OFFFH). It has a 13 bit Program counter(PC) to access any address (213-4k). This PIC family uses 13- bit program counter allowing the controllers to an 8k- program memory without changing the CPU structure.

Two addresses in the program memory address space are treated in a special way by the CPU. The first address H'000' being a go to mainline instruction the second special address, H' 004' being a 'go to in service' instruction can be assigned to this address to make the CPU to jump to the beginning of the Interrupt Service routine located elsewhere in the memory space. When we deal with tables, they are assigned to addresses in the range H'005 - H'OFF' because for most of the applications this space is sufficient. The main line program begins after the tables.

DATA MEMORY The data memory of PIC 16F8XX is partitioned into multiple banks which contain the general-purpose registers and the Special function Registers. (SFRs). The bits RP1 and RPO bits of the status register are used to select these banks. Each bank extends up to 7FH (128 Bytes). The lower bytes of the each bank are reserved for the Special Function Registers. Above the SFRS are general purpose registers implemented as static RAM.

7. Asynchronous communication of PIC16F873 

When doing a data communication, the condition of "O" and "1" to have let out from the side of the sending it must be able to be recognized in the receiving side. In the asynchronous communication, it puts a start bit to the head of the transferred data (8 bits or 9 bits) and it puts a stop bit at the end of the data. Recognition in the data block is done by it. The start bit is an L level and the stop bit is the signal of the H level.

The circuit of the condition not to transfer data is H level. When becoming an L level (Start bit) from this condition, the receiving side recognizes that the data transfer begins. After that, according to the signalling speed, the transfer of the data is done. The transfer of the block ends when a stop bit (H level) is detected last. A signalling speed is controlled by the timer which is independent in the sender and the receiving side. So, it isn't possible to do correct communication when there is an error in this timer.

In the asynchronous mode communication of USART, the RX port is used for receiving and the TX port is used for the transmission, so, it is possible to send and receive at the same time. (Full duplex)