PJK.c

#include <LPC17xx.h>
#include <stdio.h>
#include <string.h>

#define DATA_CTRL 0xF << 15
#define RS_CTRL 0x1 << 19
#define EN_CTRL 0x1 << 20
#define LED_CTRL 0xFF << 4

#define ALARM_DELAY 1000000
#define SAFE_DELAY 1000000

/*
CND - P0.24 - 1rst pin -> sensor analog input (function 1) (top right-most pin)
CNB - P2.10 - 5th pin -> relay
CNB - P2.13 - 8th pin -> buzzer
CNC - P0.20 - P0.15 -> LCD
CNA - P0.11 - P0.4 -> LED
CNB - P2.11 - 6th pin -> UNSAFE -ve edge triggered - External Interrupt 1
CNB - P2.12 - 7nth pin -> SAFE +ve edge triggered - External Interrupt 2

Checks:
1 ADC jumper set to left
2 pins connected properly
*/

void delay(unsigned int);
void lcd_init(void);
void lcd_puts(unsigned char *);
void lcd_write(unsigned int is_cmd);
void clear_ports(void);
void port_write(unsigned int is_cmd);

extern unsigned long int temp1, temp2;
unsigned long int temp1 = 0, temp2 = 0;

unsigned int adc_temp = 8081, state;

unsigned char lcd_line_1[50] = "GAS LEAK DETECTo";
unsigned char lcd_line_2[50] = "";

void ADC_IRQHandler()
{
    unsigned int x, temp;

    /*x = LPC_ADC->ADSTAT;
    if (x & (3 << 0) == (1 << 0))
        ;*/

    // check bit 31 done flag
    if (!(temp = LPC_ADC->ADDR4) & (1 << 31))
    {
        return;
    }

    adc_temp = (temp >> 4) & 0xFFF;

    sprintf(lcd_line_2, "%s | %u    ", state ? "LEAK" : "SAFE", adc_temp);

    LPC_GPIO0->FIOMASK = LED_CTRL;

    temp1 = 0xC0;
    lcd_write(0);
    delay(800);
    lcd_puts(&lcd_line_2[0]);
}

void EINT1_IRQHandler(void)
{
    // clear interrupt EINT1 - negative edge on CNB pin 6 - P2.11
    LPC_SC->EXTINT &= 1 << 1;

    // leak detected - perform alarm actions in main() while loop
    state = 1;
}

void EINT2_IRQHandler(void)
{
    // clear interrupt EINT2 - positive edge on CNB pin 7 - P2.12
    LPC_SC->EXTINT &= 1 << 2;

    // no leak present - disable alarms
    state = 0;

    LPC_GPIO0->FIOMASK = RS_CTRL | EN_CTRL | DATA_CTRL;

    // relay ON buzzer OFF LED OFF
    LPC_GPIO0->FIOPIN = 0;                     // LED OFF
    LPC_GPIO2->FIOPIN = (1 << 10) | (0 << 13); // relay ON | buzzer OFF
}

int main(void)
{
    SystemInit();
    SystemCoreClockUpdate();

    // Set P2.10 (relay) & P2.13 (buzzer) as output
    LPC_GPIO2->FIODIR = (1 << 10) | (1 << 13);

    // Set P0.21-P0.15 as LCD output and P0.11-P0.4 as LED output
    LPC_GPIO0->FIODIR = RS_CTRL | EN_CTRL | DATA_CTRL | LED_CTRL;

    // Set CNB pin 6 - P2.11 & CNB pin 7 - P2.12 as external interrupt
    LPC_PINCON->PINSEL4 = (1 << 22) | (1 << 24);

    // edge triggered interrupt for both EINT1 & EINT2
    LPC_SC->EXTMODE = (1 << 1) | (1 << 2);

    // EINT1: -negative edge | EINT2: positive edge triggered
    LPC_SC->POLAR = (0 << 1) | (1 << 2);

    // enable external interrupt globally in NVIC block
    NVIC_Enable_IRQ(EINT1_IRQn);
    NVIC_Enable_IRQ(EINT2_IRQn);

    lcd_init();

    // display project title
    temp1 = 0x80;
    lcd_write(0);
    delay(800);
    lcd_puts(&lcd_line_1[0]);

    // enable ADC CH0 at P0.23 (connected to sensor analog input - CND first pin)
    LPC_PINCON->PINSEL1 = 1 << 14;
    LPC_SC->PCONP |= (1 << 12);
    LPC_ADC->ADCR = (1 << 0) | (1 << 21) | (1 << 16); // burst mode channel 0
    LPC_ADC->ADINTEN = (1 << 0);                      // enable interrupt on ADC CH0 scan
    NVIC_EnableIRQ(ADC_IRQn);                         // enable ADC interrupts globally

    while (1)
    {
        // trigger alarm actions only if state is 1 i.e. gas leak detected
        if (!state)
        {
            continue;
        }

        LPC_GPIO0->FIOMASK = RS_CTRL | EN_CTRL | DATA_CTRL;

        // toggle buzzer and LED while keeping relay OFF
        LPC_GPIO0->FIOPIN = 0xFF << 4;             // LED ON
        LPC_GPIO2->FIOPIN = (0 << 10) | (1 << 13); // relay OFF | buzzer ON
        delay(ALARM_DELAY);
        LPC_GPIO0->FIOPIN = 0;                     // LED OFF
        LPC_GPIO2->FIOPIN = (0 << 10) | (0 << 13); // relay OFF | buzzer OFF
        delay(ALARM_DELAY);
    }
}

void delay(unsigned int limit)
{
    unsigned int i;
    for (i = 0; i < limit; i++)
        ;
    return;
}

void lcd_init()
{
    clear_ports();
    delay(3200);
    temp2 = (0x30 << 15);
    port_write(0);
    delay(30000);
    temp2 = (0x30 << 15);
    port_write(0);
    delay(30000);
    temp2 = (0x30 << 15);
    port_write(0);
    delay(30000);
    temp2 = (0x20 << 15);
    port_write(0);
    delay(30000);
    temp1 = 0x28;
    lcd_write(0);
    delay(30000);
    temp1 = 0x0C;
    lcd_write(0);
    delay(800);
    temp1 = 0x06;
    lcd_write(0);
    delay(800);
    temp1 = 0x01;
    lcd_write(0);
    delay(10000);
    temp1 = 0x80;
    lcd_write(0);
    delay(800);
    return;
}

void lcd_puts(unsigned char *buffer)
{
    unsigned int i = 0;
    while (buffer[i] != '\0')
    {
        temp1 = buffer[i++];
        lcd_write(1);

        if (i == 16)
        {
            temp1 = 0xC0;
            lcd_write(0);
            break;
        }
    }
    return;
}

void lcd_write(unsigned int is_data)
{
    temp2 = temp1 & 0xF0;
    temp2 = temp2 << 11;
    port_write(is_data);
    temp2 = temp1 & 0x0F;
    temp2 = temp2 << 15;
    port_write(is_data);
    delay(1000);
    return;
}

void clear_ports(void)
{
    LPC_GPIO0->FIOCLR = 0xF << 15;
    LPC_GPIO0->FIOCLR = RS_CTRL;
    LPC_GPIO0->FIOCLR = EN_CTRL;
    return;
}

void port_write(unsigned int is_data)
{
    clear_ports();
    LPC_GPIO0->FIOPIN = temp2;

    (is_data) ? (LPC_GPIO0->FIOSET = RS_CTRL) : (LPC_GPIO0->FIOCLR = RS_CTRL);

    LPC_GPIO0->FIOSET = EN_CTRL;
    delay(25);
    LPC_GPIO0->FIOCLR = EN_CTRL;
    return;
}