added xxtea code for arm

firmware/basic/Makefile

@@ -12,6 +12,7 @@ OBJS += keyin.o
 OBJS += uuid.o
 OBJS += crc.o
 OBJS += menu.o
+OBJS += xxtea.o
 
 LIBNAME=basic
 

firmware/basic/voltage.c

@@ -6,6 +6,7 @@ uint32_t results=5000;
 
 void VoltageCheck(void){
 
+    return;
 	results = adcRead(1);
 	results *= 10560;
 	results /= 1024;

firmware/basic/xxtea.c

@@ -0,0 +1,51 @@
+/* simple XXTEA en/decrypt utility
+ * 
+ * BSD Licence
+ *
+ * btea function is from 
+ * <https://secure.wikimedia.org/wikipedia/en/wiki/XXTEA#Reference_code>
+ *
+ * (c) by Sec <sec@42.org> 6/2011
+ */
+
+#include <stdint.h>
+
+#define DELTA 0x9e3779b9
+#define MX (((z>>5^y<<2) + (y>>3^z<<4)) ^ ((sum^y) + (k[(p&3)^e] ^ z)))
+
+void xxtea_encode(uint32_t *v, int n, uint32_t const k[4]) {
+    uint32_t y, z, sum;
+    unsigned p, rounds, e;
+    rounds = 6 + 52/n;
+    sum = 0;
+    z = v[n-1];
+    do {
+        sum += DELTA;
+        e = (sum >> 2) & 3;
+        for (p=0; p<n-1; p++) {
+            y = v[p+1]; 
+            z = v[p] += MX;
+        }
+        y = v[0];
+        z = v[n-1] += MX;
+    } while (--rounds);
+}
+
+void xxtea_decode(uint32_t *v, int n, uint32_t const k[4]) {
+    uint32_t y, z, sum;
+    unsigned p, rounds, e;
+
+    rounds = 6 + 52/n;
+    sum = rounds*DELTA;
+    y = v[0];
+    do {
+        e = (sum >> 2) & 3;
+        for (p=n-1; p>0; p--) {
+            z = v[p-1];
+            y = v[p] -= MX;
+        }
+        z = v[n-1];
+        y = v[0] -= MX;
+    } while ((sum -= DELTA) != 0);
+}
+

firmware/basic/xxtea.h

@@ -0,0 +1,8 @@
+#ifndef _XXTEA_H_
+#define _XXTEA_H_
+
+void xxtea_encode(uint32_t *v, int n, uint32_t const k[4]);
+void xxtea_decode(uint32_t *v, int n, uint32_t const k[4]);
+
+#endif
+