add cksum

[aversive.git] / projects / microb2010 / tests / beacon_tsop / main.c

diff --git a/projects/microb2010/tests/beacon_tsop/main.c b/projects/microb2010/tests/beacon_tsop/main.c
index 939719f..edc444b 100755 (executable)
--- a/projects/microb2010/tests/beacon_tsop/main.c
+++ b/projects/microb2010/tests/beacon_tsop/main.c
@@ -146,6 +146,31 @@ void debug_tsop(void)
 #endif
 }
 
+#if 0
+/* val is 16 bits, including 4 bits-cksum in MSB, return 0xFFFF is
+ * cksum is wrong, or the 12 bits value on success. */
+static uint16_t verify_cksum(uint16_t val)
+{
+       uint16_t x, cksum;
+
+       x = (val & 0xfff);
+       /* add the four 4-bits blocks of val together */
+       cksum = val & 0xf;
+       val = val >> 4;
+       cksum += val & 0xf;
+       cksum = (cksum & 0xf) + ((cksum & 0xf0) >> 4);
+       val = val >> 4;
+       cksum += val & 0xf;
+       cksum = (cksum & 0xf) + ((cksum & 0xf0) >> 4);
+       val = val >> 4;
+       cksum += val & 0xf;
+       cksum = (cksum & 0xf) + ((cksum & 0xf0) >> 4);
+       if (cksum == 0xf)
+               return x;
+       return 0xffff; /* wrong cksum */
+}
+#endif
+
 /* decode frame */
 SIGNAL(SIG_TSOP) {
        static uint8_t led_cpt = 0;