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Nfc Controlled Rgb Led

Made by ashokr / Communication / Displays / Lights / Productivity

About the project

This project demonstrates the controlling of an RGB LED over NFC by smartphone.

Project info

Difficulty: Easy

Platforms: Android, NXP

Estimated time: 4 weeks

License: GNU General Public License, version 3 or later (GPL3+)

Items used in this project

Hardware components

	NXP LPC812 MAX board	x 1
	NXP NTAG I2C Board	x 1

Software apps and online services

Android Studio

Story

This project demonstrates the controlling of an RGB LED over NFC by smartphone. LPC812 MAX board is interfaced with NTAG I2C board (NT3H1101).

The LPC812 MAX board comes with RGB LED, the pin connection details are here:

P0_7 -> RED LED

P0_17 -> GREEN LED

P0_16 -> BLUE LED

NTAG I2C board needs to interfaced with LPC812, the pin details are here:

P0_11 -> SCL_NTAG

P0_10 -> SDA_NTAG

The NTAG is having total 476 pages with 4bytes per each page. In this project only one page is required (4bytes):

byte1 - Led status (On/Off)

byte2 - Red value

byte3 - Green Value

byte4 - Blue

Android application is developed using android studio, its available on google play store here.

Android application allow us to choose the color then corresponding RGB values will be write into NTAG memory by tapping it with mobile. LPC812 generates the PWM signals w.r.t the values in NTAG memory.

The working demo is here:

Schematics, diagrams and documents

NTAG I2C board connection

RGB LED connections

Code

Main

/*
 * @brief Ntag LED example using SysTick and I2C
 *
 * @note
 * Copyright(C) Ashok, NXP Semiconductors, 2013
 * All rights reserved.
 *
 */

#include "board.h"
#include <stdio.h>

/*****************************************************************************
 * Private types/enumerations/variables
 ****************************************************************************/

#define TICKRATE_HZ (160000)	/* 10 ticks per second */


/* I2CM transfer record */
static I2CM_XFER_T  i2cmXferRec;
/* System clock is set to 24MHz, I2C clock is set to 600kHz */
#define I2C_CLK_DIVIDER         (40)
/* 100KHz I2C bit-rate */
#define I2C_BITRATE             (100000)

/* 7-bit I2C addresses of I/O expander */
/* Note: The ROM code requires the address to be between bits [6:0]
         bit 7 is ignored */

#define NTAG_SLAVE_ADDRESS (0x55U)

#define RED				0x00
#define BLUE	        0x01
#define GREEN	        0x02



/*****************************************************************************
 * Public types/enumerations/variables
 ****************************************************************************/

/*****************************************************************************
 * Private functions
 ****************************************************************************/

/*****************************************************************************
 * Public functions
 ****************************************************************************/

struct Channel{

	volatile uint8_t ONTime;
	volatile int8_t Offset;
	volatile uint8_t Enabled;
}r,g,b;

/*variables */
volatile uint32_t msTicks=0;
volatile uint32_t readTaskTicks=0;
volatile uint8_t RxData[4];
volatile uint8_t led_EN=0;

static uint8_t txData[16];
static uint8_t rxData[16];

/*****************************************************************************
 * Public types/enumerations/variables
 ****************************************************************************/

/*****************************************************************************
 * Private functions
 ****************************************************************************/

/* Initializes pin muxing for I2C interface */
static void Init_I2C_PinMux(void)
{
#if (defined(BOARD_NXP_LPCXPRESSO_812) || defined(BOARD_LPC812MAX) || defined(BOARD_NXP_LPCXPRESSO_824))
	/* Enable the clock to the Switch Matrix */
	Chip_Clock_EnablePeriphClock(SYSCTL_CLOCK_SWM);
#if defined(BOARD_NXP_LPCXPRESSO_824)
	Chip_SWM_EnableFixedPin(SWM_FIXED_I2C0_SDA);
	Chip_SWM_EnableFixedPin(SWM_FIXED_I2C0_SCL);
#else
	/* Connect the I2C_SDA and I2C_SCL signals to port pins(P0.10, P0.11) */
	Chip_SWM_MovablePinAssign(SWM_I2C_SDA_IO, 10);
	Chip_SWM_MovablePinAssign(SWM_I2C_SCL_IO, 11);
#endif

	/* Enable Fast Mode Plus for I2C pins */
	Chip_IOCON_PinSetI2CMode(LPC_IOCON, IOCON_PIO10, PIN_I2CMODE_FASTPLUS);
	Chip_IOCON_PinSetI2CMode(LPC_IOCON, IOCON_PIO11, PIN_I2CMODE_FASTPLUS);

	/* Disable the clock to the Switch Matrix to save power */
	Chip_Clock_DisablePeriphClock(SYSCTL_CLOCK_SWM);
#else
	/* Configure your own I2C pin muxing here if needed */
#warning "No I2C pin muxing defined"
#endif
}

/* Setup I2C handle and parameters */
static void setupI2CMaster()
{
	/* Enable I2C clock and reset I2C peripheral */
	Chip_I2C_Init(LPC_I2C);

	/* Setup clock rate for I2C */
	Chip_I2C_SetClockDiv(LPC_I2C, I2C_CLK_DIVIDER);

	/* Setup I2CM transfer rate */
	Chip_I2CM_SetBusSpeed(LPC_I2C, I2C_BITRATE);

	/* Enable Master Mode */
	Chip_I2CM_Enable(LPC_I2C);
}

/* Function to setup and execute I2C transfer request */
static void SetupXferRecAndExecute(uint8_t devAddr,
								   uint8_t *txBuffPtr,
								   uint16_t txSize,
								   uint8_t *rxBuffPtr,
								   uint16_t rxSize)
{
	/* Setup I2C transfer record */
	i2cmXferRec.slaveAddr = devAddr;
	i2cmXferRec.status = 0;
	i2cmXferRec.txSz = txSize;
	i2cmXferRec.rxSz = rxSize;
	i2cmXferRec.txBuff = txBuffPtr;
	i2cmXferRec.rxBuff = rxBuffPtr;

	Chip_I2CM_XferBlocking(LPC_I2C, &i2cmXferRec);
}



/* Function to Read NTAG*/
static void NTAG_Read()
{
	int index = 0;

	txData[index++] = (uint8_t) 0x01;			/* I2C device regAddr for NTAG*/

	SetupXferRecAndExecute(NTAG_SLAVE_ADDRESS, txData, index, rxData, 4);
}

static void Init_LED_Cal(){

	r.Offset = 0;
	g.Offset = 0;
	b.Offset = 0;

	r.ONTime = 0xFF;
	g.ONTime = 0xFF;
	b.ONTime = 0xFF;


}

/**
 * @brief	Handle interrupt from SysTick timer
 * @return	Nothing
 */
void SysTick_Handler(void)
{
	msTicks++;

	if(readTaskTicks > 500)
	{

		NTAG_Read();

		readTaskTicks=0;

	}


}

/**
 * @brief	main routine for blinky example
 * @return	Function should not exit.
 */
int main(void)
{
	SystemCoreClockUpdate();
	Board_Init();

	Board_LED_Set(0, false);

	/* Setup I2C pin muxing */
	Init_I2C_PinMux();

	/* Allocate I2C handle, setup I2C rate, and initialize I2C clocking */
	setupI2CMaster();

	/* Disable the interrupt for the I2C */
	NVIC_DisableIRQ(I2C_IRQn);

	/* Enable SysTick Timer */
	SysTick_Config(SystemCoreClock / TICKRATE_HZ);

	/* Load Initial values for RGB LED */
	Init_LED_Cal();


	/* Loop forever */
	while (1) {



	if(msTicks >= 255){


		readTaskTicks++;
		r.ONTime = rxData[1]+r.Offset;
		g.ONTime = rxData[2]+g.Offset;
		b.ONTime = rxData[3]+b.Offset;
		led_EN = rxData[0];

		if(led_EN>0){

			Board_LED_Set(RED, true);
			Board_LED_Set(BLUE, true);
			Board_LED_Set(GREEN, true);
			r.Enabled = true;
			g.Enabled = true;
			b.Enabled = true;
		}
		msTicks = 0;

	 }
	else if((msTicks >= r.ONTime) && r.Enabled){

		Board_LED_Set(RED, false);
		r.Enabled = false;

	}
	else if((msTicks >= g.ONTime) && g.Enabled){

		Board_LED_Set(BLUE, false);
		g.Enabled = false;

	}
	else if((msTicks >= b.ONTime ) && b.Enabled){

		Board_LED_Set(GREEN, false);
		b.Enabled = false;

	}


	//	__WFI();
	}
}

Credits

ashokr

Hello! I’m Ashok. I’m currently working as software engineer. passionate about doing Hobbies Projects and Animations works.

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