wvtc_reader.c

/*
2023-04-06

Amelia Vlahogiannis [AG2V]

WVTC RFID Access System
Uses UART to monitor an RDM6300 and trigger a relay to open the door
*/

#include "rdm6300.c"
#include <stdio.h>
#include "pico/stdlib.h"
#include "hardware/uart.h"
#include "hardware/timer.h"

#define BUFFER_SIZE 14 
#define SN_LENGTH 14

#define UART_ID uart0
#define BAUD_RATE 9600 //RDM6300 outputs 9600 baud

#define UART_TX_PIN 0
#define UART_RX_PIN 1

#define LOCKED 0
#define UNLOCK 1
#define OPEN 2

#define DOOR_PIN 15

void on_uart_rx(void);
void door_handler(int state);
int check_card_sn(unsigned char *card_id);
int hex_to_int(unsigned char *hex_string);

char read_buffer[BUFFER_SIZE]; //stores the card sn

uint8_t ch;
int i, x;
int door_state;
int card;
absolute_time_t t0, t1;

char accepted_cards[2][2] = {{0x1C, 0x00, 0x9C, 0xD4, 0x4D}, {0x1C, 0x00, 0x9C, 0xAF, 0xDB}};

int main() {


	uart_init(UART_ID, BAUD_RATE);
	gpio_set_function(UART_TX_PIN, GPIO_FUNC_UART);
	gpio_set_function(UART_RX_PIN, GPIO_FUNC_UART);

	irq_set_exclusive_handler(UART0_IRQ, on_uart_rx);
	irq_set_enabled(UART0_IRQ, true);
	uart_set_irq_enables(UART_ID, true, false);


	gpio_init(DOOR_PIN);
	gpio_set_dir(DOOR_PIN, GPIO_OUT);
	gpio_put(DOOR_PIN, 0);

	gpio_init(7);
	gpio_set_dir(7, GPIO_OUT);
	gpio_put(7, 1);

	gpio_init(25);
	gpio_set_dir(25, GPIO_OUT);
	gpio_put(25, 1);

	for(;;) { 

		//int check_card_id(char *read_buffer); returns a 1 or 0 for valid or no
		door_handler(door_state);
	}
}

void on_uart_rx(void) {
	i = 0;
	while(uart_is_readable(UART_ID) && i < SN_LENGTH) {
		read_buffer[i] = uart_getc(UART_ID);
		i++;
	}

	read_buffer[i] = '\0';
	x = 0;
	while(x < i) {
		if(uart_is_writable(UART_ID)){
		       	uart_putc(UART_ID, read_buffer[x]);
		}
		x++;
	}	
	card = hex_to_int(&read_buffer); 
}

void door_handler(int state) {
	switch(state) {
		case LOCKED :
			gpio_put(DOOR_PIN, 0);
			break;
		case UNLOCK:
			gpio_put(DOOR_PIN, 1);
			//timer = 0;
			door_state = OPEN;
			break;
		case OPEN :
			gpio_put(DOOR_PIN, 1);
			//if(timer > 5000) door state = LOCKED;
			break;
		//case UNLATCHED : //for the open/closed sensor when implemented
	}

}

int hex_to_int(unsigned char *hex_string) {
  int result = 0;
  int i = 0;
  while (hex_string[i] != '\0') {
    int digit = hex_string[i] - '0';
    if (digit > 9) {
      digit = hex_string[i] - 'A' + 10;
    }
    result = result * 16 + digit;
    i++;
  }
  return result;
}