Exploring PIC 24F series Microcontroller using MPLAB and Proteus

JOURNAL OF CURRENT RESEARCH IN SCIENCE ISSN 2322-5009 CODEN (USA): JCRSDJ Available at www.jcrs010.com

JCRS 4 (2), 2016: 164-176

Exploring PIC 24F series Microcontroller using MPLAB and Proteus Sohaib Aslam1*, Sundas Hannan2, Arsalan Haider3, Mohammad Hamza Tariq 4 Department of Electrical Engineering, Superior University, Lahore, Pakistan. Corresponding Author email: [email protected]

K E Y W O R D S: Interrupt Service Routine (ISR), Keypad, Liquid Crystal Display (LCD), Univeral Asynchronous Receiver Transmitter (UART), Pulse Width Modulation (PWM), PORT ABSTRACT: This paper aims at explore the working of a 16-bit Peripheral Interface Controller (PIC) 24F series microcontroller using MPLAB IDE and Proteus Professional software. PICs are cost-effective microcontrollers and provide a large number of applications in educational and industrial areas. 16-bit PIC microcontrollers are not explored to the best potential for their hands on experience in educational and industrial sectors. The research work demonstrates the functioning different sections of the microcontroller. Firstly Ports A and B are initialized to use for Input-Output (I/O) interfacing. Then timers are briefly explained and simulated for specific applications. Basic methodology of calling interrupts is defined using simulations. Pulse Width Modulation (PWM) is generated using Output Compare Module (OCM) of microcontroller. Interfacing of the microcontroller with Liquid Crystal Display (LCD) and Keypad through I/O ports is presented and finally Universal Asynchronous Receiver Transmitter (UART) based asynchronous serial communication at 115200 baud rate through PIC microcontroller is done in Proteus. Introduction Field of embedded systems is playing an important role in facilitating the modern society. A wide range of embedded systems are present in every sector of life like telephones, cell-phones, cameras, fax machines, baby toys, industrial control systems, medical testing systems, life support systems, avionics systems and many more (Miha & Mihael, 2008). Majorly embedded systems are based on microcontrollers. Current microcontrollers can perform operations based on hundreds of thousands of transistors. Initially microprocessors had no built in peripherals like memory, I/O lines and timers etc (Yousif, 2012). After some period of time a new device called integrated circuit (IC) came, which contains both processor and peripherals. This IC was called microcontroller (N.Barsoum, 2010). Peripheral Interface Controllers (PICs) developed and marketed by Microchip technology, Inc. are cost effective units with built in central processing unit (CPU), I/O functions, memory and timers etc (S.H.LEE et al, 2004). In 1989 first 8-bit PIC microcontroller with small amount of data ram, data rom , one timer and small number of I/O lines on single 8-pin IC was introduced. It is surprising to see that within a decade Microchip becomes the top ranked supplier of 8-bit controllers (M.A.Mazidi et al, 2008). The PIC developers introduced number of families of 8-bit controllers. i-e 10xxx, 12xxx, 14xxx, 16xxx, 17xxx and 18xxx. In 8-bit microcontrollers PIC18xxx has the highest performance among the PIC families and other famous 8-bit controller manufacturers (M.A.Mazidi et al, 2008). In recent years, with the advancement in technology and requirement of high performance in different industrial and educational projects microchip introduces 16-bit microcontroller families. These families include 24F, 24H, dspic30F and dspic33F. PIC 24F series provides a significant increase in performance from PIC 18xxx series with a slight cost impact (D.Schneider, 2006). In this research work working of PIC24FJ128GA010 microcontroller in different aspects is demonstrated by first developing the algorithm and generating the hex file using MPLAB microchip developing tool and then simulating the controller in Proteus Professional. In section 2 PIC24FJ128GA010 is precisely discussed. Section 3 deals with the software tools. Ports are initialized in section 4. Timers and Interrupts are elaborated in section 5. PWM is done in section 6. LCD and Keypad interfacing with I/O Ports of microcontroller is elaborated in section 7. Section 8 reveals the asynchronous serial communication using UART. Finally conclusion is summarized in section 9 PIC24FJ128GA010 Microcontroller PIC24FJ128GA010 belongs to CMOS family with low power consumption because of power management modes i-e sleep, idle and alternate clock modes. Its operating voltage range is 2.0 V -3.6V. it is a general purpose 100-pin microcontroller with a modified Reduced Instruction Set computer (RISC) architecture which can operate at up to 32 MHz crystal oscillator with speed of 16 Mega Instructions Per Second (MIPS) (PIC Datasheet, 2006). The controller has a C compiler optimized instruction set mechanism with dynamic addressing modes (S.Aslam , 2015). PIC24FJ128GA010

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has a data memory bus of 16-bit wide while program memory bus of 24-bit wide. Its general block diagram is shown in Figure 1.

Figure 1. PIC24FJ128GA010 General Block Diagram

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It has 128 Kilo Bytes (KB) of program memory, 8KB of RAM data memory, five 16-bit timers/counters with built in programmable prescaler. It also provides seven communication modules these are I2C, UARTs, SPIs and one Parallel Master Port (PMP) (L.D.Jasio, 2007). The peripheral features of PIC24F family are summarized in Table 1 (PIC Datasheet, 2006).

Comparators

PMP/PSP

JTAG

5 5 5 5 5 5 5 5 5

10-bit A/D (ch)

Compare/ PWM Output

Capture Input 5 5 5 5 5 5 5 5 5

I2C

5 5 5 5 5 5 5 5 5

SPI

8k 8k 8k 8k 8k 8k 8k 8k 8k

UART

64k 96k 128k 64k 96k 128k 64k 96k 128k

Timers 16-bit

64 64 64 80 80 80 100 100 100

RAM (Bytes)

Pins

PIC24FJ64GA006 PIC24FJ96GA006 PIC24FJ128GA006 PIC24FJ64GA008 PIC24FJ96GA008 PIC24FJ128GA008 PIC24FJ64GA010 PIC24FJ96GA010 PIC24FJ128GA010

ROM (Bytes)

Device

Table 1. Peripheral Summary of PIC24F Family

2 2 2 2 2 2 2 2 2

2 2 2 2 2 2 2 2 2

2 2 2 2 2 2 2 2 2

16 16 16 16 16 16 16 16 16

2 2 2 2 2 2 2 2 2

Y Y Y Y Y Y Y Y Y

Y Y Y Y Y Y Y Y Y

Software Tools The software tools used in this research work to develop the applications for PIC microcontroller and simulate them are MPLAB and Proteus respectively. They are precisely discussed below MPLAB IDE MPLAB Integrated Development Environment (IDE) is best described as software to develop programs for PIC microcontrollers. It is called IDE because development, debugging and software services are simultaneously available on a single platform (MPLAB Guide, 2004). The Language tools offered by MPLAB include Assembler (MPASM), Linker (MPLINK) and a C compiler (MPLAB C30) (M.A.Mokhtar, 2009). The latest version available at the time of this writing is MPLAB X IDE but in this research work MPLAB 8.10 version with C 30 compiler is used. The steps required to develop a program for the PIC controller and generate hex file using MPLAB is shown in Figure 2 (S.K.Arvind et al, 2014). Step 1 Open MPLAB

Step 2 Project Wizard

Step 3 Chose PIC24Fj128GA010

Step 4 Chose C30 Compiler

Step 5 Open Source File

Step 6 Write Code and Save

Step 7 Add source and link file

Step 8 Select Build Project

Figure 2. Steps to develop program for PIC microcontroller

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Proteus Proteus is sophisticated Electronic Design Automation (EDA) simulation software. The enormous device library and large range of peripherals are the special advantage of this simulator. The virtual instrumentation feature provides a great opportunity for simulation of microcontroller units. Proteus Virtual System Modeling (VSM) combines mixed mode SPICE circuit simulation, animated components and microprocessor models to facilitate complete simulations of microcontroller based designs. For the first time ever, it is possible to develop and test such designs before a physical prototype is constructed (J.Chen, 2011). The steps required to simulate microcontroller based applications in Proteus are shown in Figure 3. Step 1 Open Proteus

Step 2 Select ISIS

Step 3 Select Component Mode

Step 4 Select Component

Step 5 Implement Circuit

Step 6 Select Properties of Microcontroller

Step 7 Browse Hex File

Step 8 Simulate

Figure 3. Steps to Simulate PIC microcontroller Start

Include header file p24fj128ga010

Main () Initialize TRISA,TRISB,AD1PC FG While(1) Move data to both ports

End

Figure 4. Algorithm Sequence for PORTA and PORTB Ports Initialization Port is a set of pins on a microcontroller which represent physical connection of Central Processing Unit (CPU) with the outer world and microcontroller utilizes them to control or monitor other systems (N.Matic, 2003). There are six

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ports in PIC24FJ128GA010 they are A, B, C, D, E, F and G. All these ports can be used as inputs or outputs according to the requirement of the application of microcontroller. . By default all Port B pins are multiplexed with analog inputs so to use them as output they must be connected to digital inputs (L.D.Jasio, 2007). To initialize ports as input or output and to connect Port B pins to digital inputs TRISX and AD1PCFG control registers are used where X identifies port. By default at reset all I/O pins are configured as input so to initialize Port as output 0x0000 must be sent to TRISX and to connect I/O pins to digital inputs 0xFFFF is sent to AD1PCFG. In this section Port A and Port B are initialized as outputs and Port B pins are connected to digital inputs so that information on Port B pins can be read by external device then toggling of first 4 pins of both ports are done. The program is developed in MPLAB using the following command sequence shown in Figure 4. In the first step of Figure 4. header file of PIC24FJ128GA010 is included which is not a proper c statement but a pseudo- instruction for the pre-processor to read the device related information before proceeding further. In main function initialization of control registers is done and finally the given data is sent to the output via both ports. The simulations of PORTS A and B are done in proteus and shown in Figure 5.

(a) Implementation of Circuit Diagram in Proteus (b) Toggling of PORTA and PORTB Figure 5. Simulation of PORTA and PORTB in Proteus In Figure 5(a) implementation of circuit diagram in proteus is shown and Figure. 5(b) shows the toggling of first four pins of both ports on digital oscilloscope using the VSM feature of proteus. Timers and Interrupts Description of timers and interrupt mechanism for PIC24FJ128GA010 is discussed below. Timers Timers are the basic peripherals of each microcontroller and provide number of features like timer, counter, internal and external interrupts and A/D event trigger (Z. Milivojević & D. Šaponjić, 2008). PIC24FJ128GA010 microcontroller offers five 16-bit timers while timer 2/3 and timer 2/4 can also be used together to give 32-bit timer or counter. The working modes and different features offered by timers are activated by the appropriate bits in TXCON control registers (PIC Datasheet, 2006). In this section application of timer 1 to generate delay is first elaborated then developed and finally simulated. Two special function registers are used in timer 1 applications they are TMR1 a 16-bit counter and PR1 to produce a periodic reset mostly used for interrupt purposes (L.D.Jasio, 2007). T1CON is a 16-bit control register shown in Figure 6 (L.D.Jasio, 2007).

Figure 6. T1CON: Timer 1 Control Register

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The bits of timer1 control register are precisely defined below TON bit is to activate timer 1. TSIDL defines the behavior in idle mode TGATE and TSYNC bits are used if other than MCU internal clock is used as timer clock. TCKPS bits are used to select different level of prescaler to decide after how many clocks of MCU internal clock TMR1 should be incremented TCS bit is used to select clock source and it is set to 0 if MCU main clock source is going to be used To use timer 1for delay purpose T1CON should be configured as TON bit must be set to 1, TSIDL bit is of no concern for this purpose, TGATE, TSYNC and TCS are also set to 0 because MCU internal clock of 32MHz is used as clock source and TCS bits are set to (11)2 for maximum prescaler of 1: 256 as it has four options 1:1, 1:8, 1:16, 1:256 so T1CON is initiated by moving 0x8030 in it. To produce delay of specific time Eq (1). is used. (

)

Where, Tdelay is the time for delay, FOSC is the frequency of MCU oscillator and Delay is the value of clocks required for particular delay. To visualize delay in simulations first four pins of PORTA are toggled with ON time of 256 ms and OFF time of 160 ms. Delay of 16000 and 10000 is calculated for 256 ms and 160 ms of time delay respectively. This program is developed in MPLAB using the following command sequence shown in Figure 7. Start

Include header file p24fj128ga010

Main () Initialize TRISA,T1CON

While(1) Toggle ON Insert Delay1 Toggle OFF Insert Delay2

End

Figure 7. Algorithm Sequence to generate Delay The simulation results of above program developed in MPLAB is shown in Figure 8 Interrupts Interrupts are sudden events in continuous flow of execution of series of commands (Z. Milivojević & D. Šaponjić, 2008). PIC 24F family has a dynamic interrupt system which can manage 118 distinctive sources of interrupts. These interrupts are classified as internal and external interrupts. Internal interrupt sources are timers, A/D converter, Analog Compare Module etc while external interrupt sources include pins for level trigger detection, Pins connected to change notification module, UARTS etc. Each interrupt source has unique piece of code which is called Interrupt Service Routine (ISR). The syntax used for this ISR is given below. Void _ISR _X1Interrupt (void) {// ISR Code here} Where, X shows the source of interrupt. Each interrupt source has five associated control bits they are; Interrupt Enable (_IE), Interrupt Flag (_IF) and three bits of Interrupt Priority level (IPL0-IPL2). IE bit must be set to 1 to enable interrupt, IF bit must be cleared at the end of ISR to ensure that same ISR is not immediately called again and IP bits set the priority of the interrupt source. Interrupt sources have maximum of 7 priority levels to resolve the issue of occurrence of two interrupts simultaneously by responding to the interrupt with higher priority level. Another important bit is _NSTDIS to avoid interrupting a low priority level interrupt by a high priority level interrupt so this bit must be set to 1. In this section timer 1 is elaborated as an internal interrupt source by setting a pin of PORTA to high for 100 ms after that interrupt will be generated and in ISR PORTA pin will set to low and PORTB pin will be set to high immediately for 50ms. The required number of clock pulses to generate 160 ms is calculated from (1) and that value will be given to PR1 register of timer 1 while delay of 50 ms in ISR is generated using timer2. The application of timer 1 as an internal interrupt source is developed in MPLAB by following the sequence of commands shown in Figure 9.

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(a) Implementation of Circuit Diagram in Proteus (b) Toggling of PORTA with Delay Figure 8. Simulation of Toggling PORTA with Delay The above figure shows the implementation of circuit in proteus and the simulation results of toggling PORTA pins with 256ms ON time and 160 ms OFF time. Start

Include header file p24fj128ga010

Write ISR for Timer 1 Interrupt

Main () Initialize PORTA, PORTB, Interrupt Control bits and PR1

While(1) Move data to Port A

End

Figure 9. Algorithm Sequence for Interrupt using Timer 1 The simulation results of above program developed in MPLAB is shown in Figure 10.

(a) Implementation of Circuit Diagram in Proteus (b) Toggling of Pins with Interuppt Figure 10. Simulation of Internal Interrupt using Timer 1 The above figure shows the circuit implementation, PORTA and PORTB pins are connected to channel A and channel B of digital Oscilloscope respectively. It is clear from the simulation that first PORTA pin remains high for 100

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ms and after interrupt is occurred PORTA pin is set to low and PORTB pin is set to high and it remains high for 50ms and this sequence continues. PWM Generation Using OCM Module PWM is a smart technique of delivering different amounts of electrical power between fully ON and fully OFF. A normal power switch with some power source provides full power only, when switched on. PWM is a relatively new technique, and can be developed by the recent electronic power switches (A.K.Dewangan et al, 2012). In PIC24FJ128GA010 OCM is used to generate PWM and it has three pins to generate PWM they are OC1, OC2 and OC3. OCM has number of operational modes i-e Single Compare Match Module, Double Compare Match Mode Generating and Simple PWM. OCM is initialized using OCXCON control register and for generating PWM the first three bits of OCXCON register (OCXCON) are set to (110) 2. PWM of particular frequency is generated by writing the number of cycles required to produce PWM period to period register of selected timer. The period register value is calculated by using the following Eq. (2) (PIC Datasheet, 2006). [ ] Where PWM frequency = 1/[PWM Period] and TCY =2/FOSC The duty cycle of PWM is set by writing its value in OCXRS register while the initial value of duty cycle is first written to OCXR register then OCXR register becomes Read-Only duty cycle register after the OCXCON control register is initialized for simple PWM generation (PIC Datasheet, 2006). In this research work PWM is generated with frequency of 488 Hz using 16MHz crystal oscillator. The calculated value of clocks for period register using (2) is (7FFA) 16 and the initial value of PWM written to OCXR register is (0F)16. Timer 2 is used for generating interrupt with a frequency of 488Hz In Proteus simulation two push buttons are connected to two pins RA1 and RA2 to increase and decrease the PWM duty cycle respectively. The application of PWM generation is developed in MPLAB by following the sequence of commands shown in Figure 11. Start

Include header file p24fj128ga010

Initialize Function Timer 2 for PWM

Initialize PWM Function OC1CON, OC1R and OC1RS

Main () Initialize PORTA and call functions

While (1) Increment or Decrement Duty Cycle Using Push Buttons End

Figure 11. Algorithm Sequence for PWM generation using OCM The circuit diagram and simulation results of PWM are shown in Figure 12.

(a) Implementation of Circuit Diagram in Proteus (b) PWM generation with 50%, 75%, 100% Duty Cycle Figure 12. Simulation of PWM generation for different Duty Cycles

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Figure 12 shows the implementation of circuit and elaborates different PWM duty cycles on Digital Oscilloscope in Proteus software. LCD and Keypad Interfacing Interfacing of LCD and Keypad with PIC24FJ128GA010 is elaborated. First LCD is discussed then keypad interfacing mechanism is shown and finally a combine algorithm sequence and simulation of both LCD and keypad is shown below. LCD Interfacing LCD is used to show real time results and found in number of applications. In this research work a 16*2 display LCD module is used. A 16*2 LCD has 16 characters in each line and there are two such lines. LCD operations are based on two registers namely command and data where command register controls the operation and data register stores the data to be displayed. The pin description of LCD is shown in Table 2 ( (S.Priyan & P.Selvaraj, 2014).

Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Table 2. Pin Description of 16*2 LCD Function Ground 0V Supply Voltage 5V Contrast adjustment through a variable resistor Selects command register when low and data register when high Low to write to the register, High to read from the register Sends data to data pins when a high to low pulse is given

8-bit data pins

Backlight VCC (5V) Backlight Ground (0V)

Name Ground VCC VEE Register Select Read/Write Enable DB0 DB1 DB2 DB3 DB4 DB5 DB6 DB7 LED+ LED-

For LCD interfacing pin numbers 1, 3 and 5 are commonly connected to ground while pin number 2 is connected to supply voltage. Other control and data pins are connected to the defined pins of PORT B from RB0-RB9. To define a PORT B pin for LCD enable pin following command syntax is used # define Enable _LCD _RB9 Similarly all the remaining control pins are defined to pins of PORT B and the direction of the pins is initiated as output by TRISB control register. There are some commands to initialize LCD for different functions which are given below: lcdcmd (0x38) //Configure the LCD in 8-bit mode, 2nd line and 5×7 font lcdcmd (0x0C) // Display On and Cursor Off lcdcmd (0x01) // Clear display screen lcdcmd (0x06) // Increment cursor lcdcmd (0x80) // Set cursor position to 1st line,1st column lcdcmd (0xC0) // Set cursor position to 2 nd line and 1st column lcdcmd (0x0F) // Display On; Cursor On; Blink On Interfacing of LCD with the microcontroller requires few functions to be declared before the main function so that they can be called in main function for sending data to LCD. These functions include initialize LCD, clear screen, toggling enable pin, write data and write string. In initialization function direction of all PORT B pins are initiated as output using TRISB register and are connected to digital inputs using AD1PCFG register then all LCD commands are declared. Clear function involves two commands of LCD 0x01 and 0x06. In toggling function enable bit is send a high to low pulse to make LCD ready to receive data. In write function RS pin is set to high then toggling function is called and finally data is sent to LCD through RB0-RB7. In write string function finally string is displayed on LCD by calling write data function. In main function all the above functions are called and then string is continuously displayed and cleared on LCD.

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Keypad Interfacing In this paper a 4*4 keypad is used in demonstration of keypad interfacing. The keypad uses its internal libraries to enable scanning of 4*4 switch array and return the data related with the pressed button. The keypad has 4 pins for its Rows[0:3] and 4 pins for its Col[0:3] and all the pins can be connected to any port and in any order so there is no requirement to use sequential pins (Keypad Datasheet, 2013). Interfacing can be done in three ways depending on the design requirements and pin resources. They are scanning method, logic change interrupt method and external interrupt using IC. In this demonstration scanning method is used which needs 8 pins for interfacing. For keypad interfacing and recognition of the pressed key by microcontroller few functions are declared outside the main function they are; initialize keypad, scan individual column, scan keypad and get key. In initialization rows of keypad are defined at RA0-RA3 and columns are defined at RA4-RA7. RA0-RA3 are initialized as inputs and RA4-RA7 are initialized as outputs and they are set to high. Scan individual column recognizes the column pressed by verifying which column has 0 value as all the columns are set to high initially. This recognition is done by following the syntax given below: Void Scan Individual Column (unsigned char COL Number){ If (COL Number==0) { COL 0=0; COL 1=1; COL 2=1; COL 3=1; } Similarly all columns are scanned using else if condition. In scan keypad function scan individual columns are initialized with each row is scanned to identify which key is pressed and return the value of dialed digit. This is done by the following syntax: Char Scan Keypad (void) { // for first column Scan Individual Column(0); //Scanning Column 0 If (!ROW0) // Scanning Row 0 Return “7”; } Similarly all other rows are scanned for col [0] and for all other columns. Finally in get key function return value is taken from scan keypad function. In the main function these external defined functions are called to recognize the pressed key by the microcontroller and which will be further displayed on LCD by using the LCD interfacing methodology. The combined application of LCD and keypad interfacing is developed in MPLAB by following the sequence of algorithm shown in Figure 13. Start

Include header file p24fj128ga010

Define Pin Connections of LCD and Keypad

Declare Functions of LCD i-e Initialization, Clear Screen, Toggling, Write Data and Write String Declare Functions of Keypad i-e Initialize, Scan Individual Column, Scan Keypad and Get Key

Main() Call Functions of LCD and Keypad

While(1) Continuously get Character of Pressed Key and Display on LCD

End

Figure 13. Algorithm Sequence for LCD and Keypad Interfacing

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The circuit diagram and simulation results of LCD and Keypad interfacing is shown in Figure 14.

(a) Implementation of Circuit Diagram in Proteus (b) Display Result on LCD Figure 14. Simulations of LCD and Keypad Interfacing Figure 14 shows the circuit implementation and simulation results on LCD in Proteus. First a simple welcome note is displayed on LCD to test LCD and then the key pressed on the keypad is displayed to verify the interfacing of keypad. UART Communication UART is an asynchronous communication interface which does not require clock line for synchronization. The data is sent and received by two data lines Tx and Rx respectively and optionally two lines RTS and CTS can be used to provide hardware handshake. Synchronization between transmitter and receiver in this communication is achieved by mining the timing information from the data information itself which include proper start and stop bits and defined fixed baud rate (L.D.Jasio, 2007). UART communication can support data rate up to 500 kb/s and can support a range of devices from 1 (RS232 standard) to 256 (RS485 standard) (L.D.Jasio, 2007). UART serial communication is based on number of parameters which include baud rate, number of data bits, parity bit if present, number of stop bits and hardware handshake. In this research work baud rate is 115200 , 8 data bits, no parity bit and 1 stop bit is used and hardware handshake is achieved through CTS and RTS lines. There are two UARTs in PIC24FJ128GA010. UART is initialized by UXMODE control register. U1MODE is a 16-bit control register shown in Figure 15.

Figure 15.U1MODE: UART1 Control Register The bits of control register used for basic demonstration of UART are briefly defined below (PIC Datasheet, 2006) : UARTEN bit is used to activate UART UEN bits are used for following functions 11= UxTX, UxRX pins are enabled and used, UxCTS pin is controlled by PORT latches 10= UxTX, UxRX, UxCTS, UxRTS pins are enabled and used 01= UxTX, UxRX and UxRTS pins are enabled and used , UxCTS pin is controlled by PORT latches 00= UxTX and UxRX pins are enabled and used , UxCTS and UxRTS are controlled by PORT latches BRGH bit is used to enable or disable high baud rate generator PDSEL bits are used to select number of data bits and parity STSEL bit is used to define one or two stop bits are used In this demonstration UARTEN bit is set to high to activate UART. UEN bits are remained low. As PIC24F family provide two modes of baud rate generation high speed and standard speed so BRGH bit is set high in this work. To

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set baud rate of 115200 Baud Rate Generator (BREG1), a 16-bit counter feeds on the peripheral clock is used. A simple formula used to calculate the value needed for BRG1 to generate required baud rate is given in Eq. (3). (

)

Where, FOSC is the frequency of Oscillator and FOSC used in this work is 32 MHz and calculated value of BREG1 using the above relation.is 34. PDSEL bits and STSEL bit are all set to low to enable 8-bit data transmission, 1 stop bit with no parity. Hardware handshake is very crucial when UART is communicating with windows terminal application, as windows perform multi tasks which results in unspecific long delays causing a great loss of data. For hardware handshaking one I/O pin is used as an input for clear to send (CTS), which senses when the windows terminal is ready to receive a new character from microcontroller and another I/O pin is initiated as output for ready to send (RTS), which indicates the terminal that controller is ready to receive new data. Another register which is used to enable the transmit pin of UART and shows the status of transmitter and receiver buffers by UTXBF and URXDA flags is known as Status and Control register (U1STA) (L.D.Jasio, 2007).UART communication involves initialization of U1MODE, U1STA BREG 1 registers. To send data to terminal first CTS is examined if gets 0 keep an eye on status of transmit buffer flag UTXBF to become low and write data to U1TXREG to send data similarly to receive data first assert RTS line to gets low then wait for the new character to be arrived using U1RXDA flag register and place that data to U1RXREG. The program for UART communication is developed in MPLAB by following the sequence of algorithm shown in Figure 16. Start

Include header file p24fj128ga010

Define Pin Connections for RTS, CTS and set their direction

Declare Function to send data

Declare Function to receive data

Main() Initialize UART registers

While(1) Call functions for sending and receiving dat

End

Figure 16. Algorithm Sequence for UART Communication The circuit diagram and simulation results of UART communication is shown in Figure 17.

(a) Implementation of Circuit Diagram in Proteus (b) Display Result on Virtual Terminal Figure 17. Simulations of UART Communication

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Figure 17 shows the circuit implementation and simulation of UART communication. The transmitted message is displayed on Virtual Terminal in Proteus which plays the same role as hyper terminal in windows to test serial transmission and results have shown that data has been successfully transmitted. Conclusion In this research work PIC24FJ128GA010 is explored by developing and simulating number of applications of PIC24F series microcontroller i-e toggling of port pins, initialization of interrupts, PWM generation, LCD and keypad interfacing and UART based serial communication by using MPLAB and Proteus software tools respectively. Simulations have recognized that these two software tools provide a powerful combination to develop and test numerous applications of PIC24F microcontroller before their real time hardware implementation. Moreover, this paper also advocates the idea of using the combination of these two tools in educational sector to enhance embedded system skills. In future prospect these tools can be used to explore other latest PIC 32-bit microcontrollers and will also provide a great help in the development of PIC24F demonstration board for learning purposes. References Arvind SK, Arun TA, Madhukar TS.2014. Speed Control of DC motor using PIC16F877A Microcontroller. Multidisciplinary Journal of Research in Engineering and Technology. 223-234. Aslam S.2015. Implementation of Model Predictive Control on a 16-bit Microcontroller for speed control of a DC motor. Dissertation, COMSATS. Barsoum N. 2010. Speed Control of the Induction Drive by Temperature and Light Sensors via PIC. 53-59. Chen J. 2011. Application of Proteus Software in MCU teaching. Second International Conference on Mechanic Automation and Control Engineering. 6359-6362 Cypress Perform, “4*4 Keypad” , datasheet, 2013. Dewangan AK., Chakarborty N. 2012. PWM based Automatic Closed loop Speed Control of DC motor. 110-112. Jasio LD.2007. Programming 16-bit Microcontrollers in C. Elsevier, UK. Lee SH, Li YF, Kapila V.2004. Development of a Matlab-Based Graphical User Interface Environment for PIC Microcontroller Projects. Proceedings of the American Society for Engineering Education Annual Conference & Exposition. Mashadany YI. 2012. Design and Implementation of Electronic Control Trainer with PIC microcontroller. Intelligent Control and Automation. 222-228 Matic N. 2008. PIC Microcontrollers for Beginners too. MikroElectronica, Belgrade Mazidi MA, Mckinlay RD. 2008. PIC Microcontroller and Embedded Systems using Assembly and C for PIC 18. Pearson, NewJersey. Microchip Technical Staff, MPLAB IDE Quick Start Guide, Microchip, 2004. Microchip, “PIC24FJ128GA010”, datasheet , 2006 Milivojević Z, Šaponjić D.2008. Programming dsPIC MCU in C. MikroElectronica, Belgrade Mokhtar MA.2009. PIC Video Game System. Dissertation. UNIVERSITI TEKNOLOGI MALAYSIA Molnikar M, Mohorcic M. 2008. A framework for developing a microchip PIC microcontroller based applications. WSEAS Transactions on Advances in Engineering Education. 81-91. Schneider D. 2006. Introduction to the 16-bit PIC24F Microcontroller Family. WebSeminar byMicrochip Technology Inc. Sethu PP, Selvaj A, Surendar A. 2014. A wireless speed control of AC Drive system. 448-456.

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