2-way radio comm.

1 files changed, 42 insertions, 14 deletions

diff --git a/lock/back.c b/lock/back.c
index c5dc35e..9da6688 100644
--- a/lock/back.c
+++ b/lock/back.c
@@ -1,11 +1,14 @@
+/* Door back, connected to the fingerprint scanner */
+
 #include <stdint.h>
-#include <stdlib.h>
 #include <string.h>
+
 #include <avr/interrupt.h>
 #include <util/delay.h>
 
 #include "nrfm.h"
 #include "uart.h"
+#include "util.h"
 
 #define RX_PIN         PD7
 #define RX_DDR         DDRD
@@ -15,15 +18,26 @@
 #define RX_PCMSK       PCMSK2
 #define RX_PCINTVEC    PCINT2_vect
 
-static int rxdr = 0;
+// todo: atomic var
+static volatile int rxdr = 0;
+
+static inline void await_reply(void)
+{
+	uint8_t i;
+
+	radio_listen();
+	for (i = 0; i < 500 && rxdr == 0; i += 100)
+		_delay_ms(100);
+}
 
 int main(void)
 {
-	uint8_t n;
-	char s[2];
-	char buf[MAXPDLEN + 1];
+	uint8_t rxaddr[ADDRLEN] = { 194, 178, 83 };
+	uint8_t txaddr[ADDRLEN] = { 194, 178, 82 };
 
-	uint8_t rxaddr[] = { 194, 178, 83 };
+	char buf[WDLEN + 1];
+	char key[WDLEN + 1];
+	char msg[WDLEN + 1];
 
 	RX_DDR &= ~(1 << RX_PIN);
 	RX_PORT |= (1 << RX_PIN); 
@@ -39,22 +53,36 @@ int main(void)
 
 	for (;;) {
 		if (rxdr) {
-			n = radio_recv(buf, MAXPDLEN);
+			n = radio_recv(buf, WDLEN);
 			buf[n] = '\0';
-			uart_write("Received data: ");
-			uart_write(itoa(n, s, 10));
-			uart_write_line(" bytes");
 			rxdr = 0;
-			if (n > 0) {
-				uart_write("INFO: ");
-				uart_write_line(buf);
+			xor(KEY, buf, msg, WDLEN);
+			if (strncmp(msg, SYN, WDLEN) == 0) {
+				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);
+					if (strncmp(msg, LOCK, WDLEN) == 0) {
+						uart_write_line("LOCKED");
+					} else if (strncmp(msg, UNLOCK, WDLEN) == 0) {
+						uart_write_line("UNLOCKED");
+					} else {
+						uart_write("ERROR: unknown message ");
+						uart_write_line(msg);
+					}
+				}
+			} else {
+				uart_write_line("ERROR: handshake failed");
 			}
 		} else {
 			uart_write_line("No IRQ");
 			_delay_ms(2000);
 		}
 	}
-
 	return 0;
 }