Embedded Systems: May 2018

I have uploaded a series of videos on youtube on how to execute this project on my channel:
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Pulse rate detector video
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MAIN.c

#include <msp430.h>
#include "lcd"
void delay(int);
void configWDT();
void configIO();
void configIR();
void configT();
void disableT();
void int_char();

int i=0;
int j=0;
char str[4];

int main(void)
{

configWDT();

configIO();

configIR();

InitializeLcm();

ClearLcmScreen();

PrintStr("Place finger tip");
LcmSetCursorPosition(2,0);
PrintStr("on the sensor");

while(1)
{
delay(10);
//P1OUT |= BIT6;
}

}

void configWDT()
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
}

void configIO()
{
P1OUT=0x00;

P1DIR |= (BIT0 + BIT6); // P1.0 output
}

void configIR()
{
P1REN |= BIT3; // P2 Enable Pullup/Pulldown
P1OUT |= BIT3; // P2 pullup
P1IE |= BIT3; // P2 interrupt enabled
P1IES |= BIT3; // P2 Hi/lo falling edge
P1IFG &= ~(BIT3); // P2 IFG cleared just in case
_EINT();
}

void enablePulseIR()
{
P2REN |= BIT1; // P2 Enable Pullup/Pulldown
P2OUT |= BIT1; // P2 pullup
P2IE |= BIT1; // P2 interrupt enabled
P2IES |= BIT1; // P2 Hi/lo falling edge
P2IFG &= ~(BIT1); // P2 IFG cleared just in case
// _EINT();

}

void disablePulseIR()
{
P2REN &= ~BIT1; // P2 Enable Pullup/Pulldown
P2OUT &= ~BIT1; // P2 pullup
P2IE &= ~BIT1; // P2 interrupt enabled
P2IES &= ~BIT1; // P2 Hi/lo falling edge
P2IFG |= (BIT1); // P2 IFG cleared just in case

}

void configT()
{
CCTL0 = CCIE; // CCR0 interrupt enabled
CCR0 = 50000;
TACTL = TASSEL_2 + MC_1; // SMCLK, upmode
}

void disableT()
{
TACTL = 0X00;
}

void delay(int a)
{
for(;a>0;a++)
_delay_cycles(7);
}

void printResult()
{
int_char();
ClearLcmScreen();
PrintStr("Pulse Rate/min =");
LcmSetCursorPosition(2,0);
PrintStr(str);
}

#pragma vector=TIMER0_A0_VECTOR
__interrupt void Timer_A (void)
{
if(i<350) i++;
else
{
P1OUT &= (~BIT0); // Toggle P1.0
disableT();
configIR();
disablePulseIR();
j=j*4;
printResult();
i=0;
j=0;
}
}

#pragma vector=PORT1_VECTOR
__interrupt void Port_1(void)
{
if((P1IFG & 0x08) == 0x08)
{
P1OUT |= BIT0;
configT();
enablePulseIR();
P1IFG &= ~BIT3;
ClearLcmScreen();
PrintStr("Please wait :");

}
}
#pragma vector=PORT2_VECTOR
__interrupt void Port_2(void)
{
P2IE &= ~BIT1;
j++;
P2IE |= BIT1;
P2IFG &= ~BIT1;
}

void int_char()
{
int s;
s=j%10;
str[2]=(char)(s+48);
j=j/10;
s=j%10;
str[1]=(char)(s+48);
j=j/10;
s=j%10;
str[0]=(char)(s+48);
str[3]='\0';
}

lcd.h

// MSP430 LCD Code

#define LCM_DIR P1DIR

#define LCM_OUT P1OUT

// Define symbolic LCM - MCU pin mappings

// We've set DATA PIN TO 4,5,6,7 for easy translation

#define LCM_PIN_RS BIT1 // P1.1

#define LCM_PIN_EN BIT2 // P1.2

#define LCM_PIN_D7 BIT7 // P1.7

#define LCM_PIN_D6 BIT6 // P1.6

#define LCM_PIN_D5 BIT5 // P1.5

#define LCM_PIN_D4 BIT4 // P1.4

#define FALSE 0

#define TRUE 1

// Routine Desc:

// This is the function that must be called

// whenever the LCM needs to be told to

// scan it's data bus.

// Parameters:

// void.

// Return

// void.

void PulseLcm()

{

// pull EN bit low

LCM_OUT &= ~LCM_PIN_EN;

__delay_cycles(200);

// pull EN bit high

LCM_OUT |= LCM_PIN_EN;

__delay_cycles(200);

// pull EN bit low again

LCM_OUT &= (~LCM_PIN_EN);

__delay_cycles(200);

}

// Routine Desc:

// Send a byte on the data bus in the 4 bit mode

// This requires sending the data in two chunks.

// The high nibble first and then the low nible

// Parameters:

// ByteToSend - the single byte to send

// IsData - set to TRUE if the byte is character data

// FALSE if its a command

// Return

// void.

void SendByte(char ByteToSend, int IsData)

{

// clear out all pins

LCM_OUT &= (~LCM_PIN_MASK);

// set High Nibble (HN) -

// usefulness of the identity mapping

// apparent here. We can set the

// DB7 - DB4 just by setting P1.7 - P1.4

// using a simple assignment

LCM_OUT |= (ByteToSend & 0xF0);

if (IsData == TRUE)

{

LCM_OUT |= LCM_PIN_RS;

}

else

{

LCM_OUT &= ~LCM_PIN_RS;

}

// we've set up the input voltages to the LCM.

// Now tell it to read them.

PulseLcm();

// set Low Nibble (LN) -

// usefulness of the identity mapping

// apparent here. We can set the

// DB7 - DB4 just by setting P1.7 - P1.4

// using a simple assignment

LCM_OUT &= (~LCM_PIN_MASK);

LCM_OUT |= ((ByteToSend & 0x0F) << 4);

if (IsData == TRUE)

{

LCM_OUT |= LCM_PIN_RS;

}

else

{

LCM_OUT &= ~LCM_PIN_RS;

}

// we've set up the input voltages to the LCM.

// Now tell it to read them.

PulseLcm();

}

// Routine Desc:

// Set the position of the cursor on the screen

// Parameters:

// Row - zero based row number

// Col - zero based col number

// Return

// void.

void LcmSetCursorPosition(char Row, char Col)

{

char address;

// construct address from (Row, Col) pair

if (Row == 0)

{

address = 0;

}

else

{

address = 0x40;

}

address |= Col;

SendByte(0x80 | address, FALSE);

}

// Routine Desc:

// Clear the screen data and return the

// cursor to home position

// Parameters:

// void.

// Return

// void.

void ClearLcmScreen()

{

// Clear display, return home

SendByte(0x01, FALSE);

SendByte(0x02, FALSE);

}

// Routine Desc:

// Initialize the LCM after power-up.

// Note: This routine must not be called twice on the

// LCM. This is not so uncommon when the power

// for the MCU and LCM are separate.

// Parameters:

// void.

// Return

// void.

void lcd_delay()

{

__delay_cycles(100000);

}

void InitializeLcm(void)

{

// set the MSP pin configurations

// and bring them to low

LCM_DIR |= LCM_PIN_MASK;

LCM_OUT &= ~(LCM_PIN_MASK);

// wait for the LCM to warm up and reach

// active regions. Remember MSPs can power

// up much faster than the LCM.

lcd_delay();

// initialize the LCM module

// 1. Set 4-bit input

LCM_OUT &= ~LCM_PIN_RS;

LCM_OUT &= ~LCM_PIN_EN;

LCM_OUT = 0x28;

PulseLcm();

//SendByte(0x33, FALSE);

//SendByte(0x32, FALSE);

// set 4-bit input - second time.

// (as reqd by the spec.)

SendByte(0x28, FALSE);

// 2. Display on, cursor off

SendByte(0x0c, FALSE);

// 3. Cursor move auto-increment

SendByte(0x06, FALSE);

}

// Routine Desc

// Print a string of characters to the screen

// Parameters:

// Text - null terminated string of chars

// Returns

// void.

void PrintStr(char *Text)

{

char *c;

c = Text;

while ((c != 0) && (*c != 0))

{

SendByte(*c, TRUE);

c++;

}

Embedded Systems

Wednesday 9 May 2018

Pulse rate detector using MSP430 - Software/Code

MAIN.c

lcd.h