Fix #405: zero the freq.band bits on entry to LMIC_setupChannel

Author: terrillmoore

src/lmic/lmic_as923.c

@@ -224,6 +224,9 @@ bit_t LMIC_setupBand(u1_t bandidx, s1_t txpow, u2_t txcap) {
 }
 
 bit_t LMIC_setupChannel(u1_t chidx, u4_t freq, u2_t drmap, s1_t band) {
+        // zero the band bits in freq, just in case.
+        freq &= ~3;
+
         if (chidx < NUM_DEFAULT_CHANNELS) {
                 // can't disable a default channel.
                 if (freq == 0)

src/lmic/lmic_eu868.c

@@ -138,6 +138,9 @@ bit_t LMIC_setupBand(u1_t bandidx, s1_t txpow, u2_t txcap) {
 }
 
 bit_t LMIC_setupChannel(u1_t chidx, u4_t freq, u2_t drmap, s1_t band) {
+        // zero the band bits in freq, just in case.
+        freq &= ~3;
+
         if (chidx < NUM_DEFAULT_CHANNELS) {
                 // can't disable a default channel.
                 if (freq == 0)

src/lmic/lmic_in866.c

@@ -133,6 +133,9 @@ bit_t LMIC_setupBand(u1_t bandidx, s1_t txpow, u2_t txcap) {
 }
 
 bit_t LMIC_setupChannel(u1_t chidx, u4_t freq, u2_t drmap, s1_t band) {
+        // zero the band bits in freq, just in case.
+        freq &= ~3;
+
         if (chidx < NUM_DEFAULT_CHANNELS) {
                 // can't disable a default channel.
                 if (freq == 0)

src/lmic/lmic_kr920.c

@@ -144,6 +144,9 @@ bit_t LMIC_setupBand(u1_t bandidx, s1_t txpow, u2_t txcap) {
 }
 
 bit_t LMIC_setupChannel(u1_t chidx, u4_t freq, u2_t drmap, s1_t band) {
+        // zero the band bits in freq, just in case.
+        freq &= ~3;
+
         if (chidx < NUM_DEFAULT_CHANNELS) {
                 // can't disable a default channel.
                 if (freq == 0)