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/* Door back, connected to the fingerprint scanner */
#include <stdint.h>
#include <string.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include "nrfm.h"
#include "uart.h"
#include "util.h"
#define PWM_MIN 500
#define PWM_MID 1500
#define PWM_MAX 2500
#define PWM_TOP 20000
#define RX_PIN PD7
#define RX_DDR DDRD
#define RX_PORT PORTD
#define RX_PCIE PCIE2
#define RX_PCINT PCINT23
#define RX_PCMSK PCMSK2
#define RX_PCINTVEC PCINT2_vect
static char chars[] = {
'0', '8', '3', '6', 'a', 'Z', '$', '4', 'v', 'R', '@',
'E', '1', 'o', '#', ')', '2', '5', 'q', ';', '.', 'I',
'c', '7', '9', '*', 'L', 'V', '&', 'k', 'K', '!', 'm',
'N', '(', 'O', 'Q', 'A', '>', 'T', 't', '?', 'S', 'h',
'w', '/', 'n', 'W', 'l', 'M', 'e', 'H', 'j', 'g', '[',
'P', 'f', ':', 'B', ']', 'Y', '^', 'F', '%', 'C', 'x'
};
static volatile int rxdr = 0;
static uint8_t charslen = sizeof(chars) / sizeof(chars[0]);
static inline void await_reply(void)
{
int i;
radio_listen();
for (i = 0; i < 500 && rxdr == 0; i += 100)
_delay_ms(100);
}
static inline void keygen(char *buf, uint8_t n)
{
int i;
uint8_t sreg;
uint16_t idx;
sreg = SREG;
cli();
idx = TCNT1;
SREG = sreg;
for (i = 0; i < n; i++, idx++)
buf[i] = chars[(idx % charslen)] ;
buf[n - 1] = '\0';
}
static inline void timer_init(void)
{
TCCR1A |= (1 << WGM11) | (1 << COM1A1);
TCCR1B |= (1 << WGM13) | (1 << CS11);
ICR1 = PWM_TOP; /* we use the same timer for servo's PWM */
}
int main(void)
{
uint8_t n;
uint8_t rxaddr[ADDRLEN] = { 194, 178, 83 };
uint8_t txaddr[ADDRLEN] = { 194, 178, 82 };
char buf[WDLEN + 1], key[WDLEN + 1], msg[WDLEN + 1];
RX_DDR &= ~(1 << RX_PIN);
RX_PORT |= (1 << RX_PIN);
PCICR |= (1 << RX_PCIE);
RX_PCMSK |= (1 << RX_PCINT);
uart_init();
timer_init();
radio_init(rxaddr);
radio_print_config();
sei();
radio_listen();
for (;;) {
if (rxdr) {
n = radio_recv(buf, WDLEN);
buf[n] = '\0';
rxdr = 0;
xor(KEY, buf, msg, WDLEN);
uart_write("DEBUG: msg recv = ");
uart_write_line(msg);
if (strncmp(msg, SYN, WDLEN) == 0) {
keygen(key, WDLEN);
uart_write("DEBUG: session key = ");
uart_write_line(key);
xor(KEY, key, msg, WDLEN);
radio_sendto(txaddr, msg, WDLEN);
await_reply();
if (rxdr) {
n = radio_recv(buf, WDLEN);
buf[n] = '\0';
rxdr = 0;
xor(key, buf, msg, WDLEN);
uart_write("DEBUG: msg = ");
uart_write_line(msg);
xor(key, ACK, msg, WDLEN);
radio_sendto(txaddr, msg, WDLEN);
}
} else {
uart_write_line("ERROR: handshake failed");
}
} else {
uart_write_line("DEBUG: no new packets");
_delay_ms(2000);
}
}
return 0;
}
ISR(RX_PCINTVEC)
{
rxdr = 1;
}
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