After recognising having more than 4 days, I took a deep breath and heading to the working prototype. In the previous article, I have made a simple gate control. In this week I made some additional functionality and will demonstrate it on the video. The idea of this part is not allowing the miner to access mining area without the helmet (or can be any safety clothes) so providing the safety. It also records the access control which makes managing and planning easier.
The system is consist of NFC reader and NFC tag. In reality, short range RFDI system will be suitable hence NFC allows a few cms which is very short distance. However, the implementation of the system and how it works is completely the same.
Let's see how system works 
I have used the example code here (DLP-7970ABP NFC Transceiver Booster Pack | TI.com ). I made some change on the program. First, RX is not activated by the example code so I need to enable the RX pin to send the gate to open command.
// Modified code
P1SEL |= BIT1 + BIT2 ; // P1.1 = RXD, P1.2=TXD
P1SEL2 |= BIT1 + BIT2 ; // P1.1 = RXD, P1.2=TXD
// The original Code
//P1SEL |= BIT2; // P1.2=TXD
//P1SEL2 |= BIT2; // P1.2=TXD
After enabling RX, I implemented RX data received interrupt. Therefore, I need to activate the RX interrupt.
UC0IE |= UCA0RXIE; // Enable USCI_A0 RX interrupt
Then interrupt service routine to open the gate.
#pragma vector=USCIAB0RX_VECTOR
__interrupt void USCI0RX_ISR(void)
{
if (UCA0RXBUF == '1') // '1' received? open the gate
{
P1OUT |= 1;
delay_ms(5000);
P1OUT &= 0xfe;
}
else //Gate is closed
{
P1OUT &= 0xfe; // Not necessary for the current program
}
}
In the interrupt service routine program gets the information from the Ground Operations Centre. Ground Operations Centre checks whether this user is inside (it may be fake ID or user throw the helmet back 
) or the ID is valid. If the user is allowed to access, it sends "1" to gate control board. If "1" is gotten by the gate control board, it will turn on the LED (open the gate), waits 5 seconds while disabling reading activities and then turn off the LED (close the gate). Using delay inside the interrupt is a terrible idea but in this time it does what I want.
Time is running, I will make some changes on the design and shoot videos and demonstrate how the system works.
You can see all the links related to this project in the first blog: Safe & Sound Wearables - Trackable Safety Helmet for Miners #1: Introduction to Project
Here is the full code.
/*
* File Name: main.c
*
* Description: The TRF7970A is an integrated analog front end and
* data framing system for a 13.56 MHz RFID reader system.
* Built-in programming options make it suitable for a wide range
* of applications both in proximity and vicinity RFID systems.
* The reader is configured by selecting the desired protocol in
* the control registers. Direct access to all control registers
* allows fine tuning of various reader parameters as needed.
*
*
* Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/
*
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
*
* Neither the name of Texas Instruments Incorporated nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*
* DESCRIPTION:
* This example detects ISO15693, Type 2, Type 3, Type 4A, Type 4B
* NFC/RFID tags. It then indicates the Tag type through LED's on the
* TRF7970A Booster pack. Information such as tag UID's and block data is
* sent out via a UART at 115200 Baud and can be read on a Computer.
*
* The TRF7970A is an integrated analog front end and
* data framing system for a 13.56 MHz RFID reader system.
* Built-in programming options make it suitable for a wide range
* of applications both in proximity and vicinity RFID systems.
* The reader is configured by selecting the desired protocol in
* the control registers. Direct access to all control registers
* allows fine tuning of various reader parameters as needed.
*
* The TRF7970A is interfaced to a MSP430G2553 through a SPI (serial)
* interface using a hardware USCI. The MCU is the master device and
* initiates all communication with the reader.
*
* The anti-collision procedures (as described in the ISO
* standards 14443A/B and 15693) are implemented in the MCU
* firmware to help the reader detect and communicate with one
* PICC/VICC among several PICCs/VICCs.
*
* AUTHORS: Josh Wyatt
* Ralph Jacobi
*
* BUILT WITH:
* Code Composer Studio Core Edition Version: 6.0.1.00040
* (c) Copyright Texas Instruments, 2014. All rights reserved.
*****************************************************************/
//===============================================================
// Program with hardware USART and SPI communication ;
// interface with TRF7970A reader chip. ;
// ;
// PORT1.0 - HEART BEAT LED ;
// PORT1.1 - UART RX ;
// PORT1.2 - UART TX ;
// PORT1.5 - SPI DATACLK ;
// PORT1.6 - SPI MOSI TODO: Remove LED2 Jumper on G2 LaunchPad ;
// PORT1.7 - SPI MISO ;
// ;
// PORT2.7 - IRQ (INTERUPT REQUEST from TRF7970A) (XOUT on LP) ;
// PORT2.1 - SLAVE SELECT ;
// PORT2.2 - TRF7970A ENABLE ;
// PORT2.3 - ISO14443B LED ;
// PORT2.4 - ISO14443A LED ;
// PORT2.5 - ISO15693 LED ;
//===============================================================
#include "nfc_app.h"
#include "trf79xxa.h"
#include <string.h>
#include <stdbool.h>
#include "MSP430.h" // Processor specific header
void delay_ms(unsigned int ms)
{
while (ms)
{
__delay_cycles(1000);
ms--;
}
}
#pragma vector=USCIAB0RX_VECTOR
__interrupt void USCI0RX_ISR(void)
{
if (UCA0RXBUF == '1') // '1' received? open the gate
{
P1OUT |= 1;
delay_ms(9000);
P1OUT &= 0xfe;
}
else //Gate is closed
{
P1OUT &= 0xfe; // Not necessary for the current program
}
}
//===============================================================
void main(void)
{
uint8_t ui8VLOCalibCount;
char x;
// TODO: Remove LED2 Jumper on G2 LaunchPad if using it, otherwise SPI will not work.
// Stop the Watchdog timer,
WDTCTL = WDTPW + WDTHOLD;
// Select DCO to be 8 MHz
MCU_initClock();
MCU_delayMillisecond(10);
// Calibrate VLO
MCU_calculateVLOFreq();
// Set the SPI SS high
SLAVE_SELECT_PORT_SET;
SLAVE_SELECT_HIGH;
// Four millisecond delay between bringing SS high and then EN high per TRF7970A Datasheet
MCU_delayMillisecond(4);
// Set TRF Enable Pin high
TRF_ENABLE_SET;
TRF_ENABLE;
// Wait until TRF system clock started
MCU_delayMillisecond(5);
// Set up TRF initial settings
TRF79xxA_initialSettings();
TRF79xxA_setTrfPowerSetting(TRF79xxA_3V_FULL_POWER);
#ifdef ENABLE_HOST
// Set up UART
UART_setup();
#endif
// Initialize all enabled technology layers
NFC_init();
P1DIR |= 0x1;
P1OUT &= 0xfe;
UC0IE |= UCA0RXIE; // Enable USCI_A0 RX interrupt
// Enable global interrupts
__bis_SR_register(GIE);
// Enable IRQ Pin
IRQ_ON;
#ifdef ENABLE_HOST
UART_putIntroReaderMsg(RFID_READER_FW_VERSION, RFID_READER_FW_DATE);
#endif
while(1)
{
// Poll for NFC tags
NFC_findTag();
// VLO drifts with temperature and over time, so it must be periodically recalibrated
// Calibrate the VLO every 25 passes of the NFC polling routine
ui8VLOCalibCount++;
if (ui8VLOCalibCount == 25)
{
// Calibrate VLO
MCU_calculateVLOFreq();
// Reset Calibration Counter
ui8VLOCalibCount = 0;
}
}
}
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