Fix #438: use clock error in FSK rx timing

Author: terrillmoore

src/lmic/lmic_as923.c

@@ -361,14 +361,6 @@ ostime_t LMICas923_nextJoinState(void) {
 }
 #endif // !DISABLE_JOIN
 
-// txDone handling for FSK.
-void
-LMICas923_txDoneFSK(ostime_t delay, osjobcb_t func) {
-        LMIC.rxtime = LMIC.txend + delay - PRERX_FSK*us2osticksRound(160);
-        LMIC.rxsyms = RXLEN_FSK;
-        os_setTimedCallback(&LMIC.osjob, LMIC.rxtime - RX_RAMPUP, func);
-}
-
 void
 LMICas923_initJoinLoop(void) {
         // LMIC.txParam is set to 0xFF by the central code at init time.

src/lmic/lmic_bandplan_as923.h

@@ -74,13 +74,6 @@ void LMICas923_init(void);
 #undef LMICbandplan_isFSK
 #define LMICbandplan_isFSK()    (/* RX datarate */LMIC.dndr == AS923_DR_FSK)
 
-// txDone handling for FSK.
-void
-LMICas923_txDoneFSK(ostime_t delay, osjobcb_t func);
-
-#undef LMICbandplan_txDoneFSK
-#define LMICbandplan_txDoneFSK(delay, func) LMICas923_txDoneFSK(delay, func)
-
 #define LMICbandplan_getInitialDrJoin() (AS923_DR_SF10)
 
 void LMICas923_setBcnRxParams(void);

src/lmic/lmic_bandplan_eu868.h

@@ -61,13 +61,6 @@ LMICeu868_isValidBeacon1(const uint8_t *d) {
 #undef LMICbandplan_isFSK
 #define LMICbandplan_isFSK()    (/* RX datarate */LMIC.dndr == EU868_DR_FSK)
 
-// txDone handling for FSK.
-void
-LMICeu868_txDoneFSK(ostime_t delay, osjobcb_t func);
-
-#undef LMICbandplan_txDoneFSK
-#define LMICbandplan_txDoneFSK(delay, func) LMICeu868_txDoneFSK(delay, func)
-
 #define LMICbandplan_getInitialDrJoin() (EU868_DR_SF7)
 
 void LMICeu868_setBcnRxParams(void);

src/lmic/lmic_bandplan_in866.h

@@ -58,13 +58,6 @@ LMICin866_isValidBeacon1(const uint8_t *d) {
 #undef LMICbandplan_isFSK
 #define LMICbandplan_isFSK()    (/* TX datarate */LMIC.dndr == IN866_DR_FSK)
 
-// txDone handling for FSK.
-void
-LMICin866_txDoneFSK(ostime_t delay, osjobcb_t func);
-
-#undef LMICbandplan_txDoneFSK
-#define LMICbandplan_txDoneFSK(delay, func) LMICin866_txDoneFSK(delay, func)
-
 #define LMICbandplan_getInitialDrJoin() (IN866_DR_SF7)
 
 void LMICin866_setBcnRxParams(void);

src/lmic/lmic_bandplan_kr920.h

@@ -61,13 +61,6 @@ LMICkr920_isValidBeacon1(const uint8_t *d) {
 #undef LMICbandplan_isFSK
 #define LMICbandplan_isFSK()    (/* always false */ 0)
 
-// txDone handling for FSK.
-void
-LMICkr920_txDoneFSK(ostime_t delay, osjobcb_t func);
-
-#undef LMICbandplan_txDoneFSK
-#define LMICbandplan_txDoneFSK(delay, func) LMICkr920_txDoneFSK(delay, func)
-
 #define LMICbandplan_getInitialDrJoin() (KR920_DR_SF7)
 
 void LMICkr920_setBcnRxParams(void);

src/lmic/lmic_eu868.c

@@ -247,14 +247,6 @@ ostime_t LMICeu868_nextJoinState(void) {
 }
 #endif // !DISABLE_JOIN
 
-// Class A txDone handling for FSK.
-void
-LMICeu868_txDoneFSK(ostime_t delay, osjobcb_t func) {
-        LMIC.rxtime = LMIC.txend + delay - PRERX_FSK*us2osticksRound(160);
-        LMIC.rxsyms = RXLEN_FSK;
-        os_setTimedCallback(&LMIC.osjob, LMIC.rxtime - RX_RAMPUP, func);
-}
-
 // set the Rx1 dndr, rps.
 void LMICeu868_setRx1Params(void) {
     u1_t const txdr = LMIC.dndr;

src/lmic/lmic_eu_like.c

@@ -250,4 +250,33 @@ void LMICeulike_setRx1Freq(void) {
                 LMIC.freq = dlFreq;
 #endif // !DISABLE_MCMD_DlChannelReq
 }
+
+// Class A txDone handling for FSK.
+void
+LMICeulike_txDoneFSK(ostime_t delay, osjobcb_t func) {
+        LMIC.rxsyms = RXLEN_FSK;
+
+        // If a clock error is specified, compensate for it by extending the
+        // receive window
+        delay -= PRERX_FSK * us2osticksRound(160);
+
+        if (LMIC.client.clockError != 0) {
+                // Calculate how much the clock will drift maximally after delay has
+                // passed. This indicates the amount of time we can be early
+                // _or_ late.
+                ostime_t drift = (int64_t)delay * LMIC.client.clockError / MAX_CLOCK_ERROR;
+
+                // Increase the receive window by twice the maximum drift (to
+                // compensate for a slow or a fast clock).
+                // decrease the rxtime to compensate for. Note that hsym is a
+                // *half* symbol time, so the factor 2 is hidden. First check if
+                // this would overflow (which can happen if the drift is very
+                // high, or the symbol time is low at high datarates).
+                delay -= drift;
+        }
+
+        LMIC.rxtime = LMIC.txend + delay;
+        os_setTimedCallback(&LMIC.osjob, LMIC.rxtime - RX_RAMPUP, func);
+}
+
 #endif // CFG_LMIC_EU_like

src/lmic/lmic_eu_like.h

@@ -56,7 +56,8 @@ LMICeulike_isValidBeacon1(const uint8_t *d) {
 #define LMICbandplan_isFSK()    (0)
 
 // provide a default LMICbandplan_txDoneDoFSK()
-#define LMICbandplan_txDoneFSK(delay, func)      do { } while (0)
+void LMICeulike_txDoneFSK(ostime_t delay, osjobcb_t func);
+#define LMICbandplan_txDoneFSK(delay, func)     LMICeulike_txDoneFSK(delay, func)
 
 #define LMICbandplan_joinAcceptChannelClear()   LMICbandplan_initDefaultChannels(/* normal, not join */ 0)
 

src/lmic/lmic_in866.c

@@ -212,14 +212,6 @@ ostime_t LMICin866_nextJoinState(void) {
 }
 #endif // !DISABLE_JOIN
 
-// Class A txDone handling for FSK.
-void
-LMICin866_txDoneFSK(ostime_t delay, osjobcb_t func) {
-        LMIC.rxtime = LMIC.txend + delay - PRERX_FSK*us2osticksRound(160);
-        LMIC.rxsyms = RXLEN_FSK;
-        os_setTimedCallback(&LMIC.osjob, LMIC.rxtime - RX_RAMPUP, func);
-}
-
 // set the Rx1 dndr, rps.
 void LMICin866_setRx1Params(void) {
     u1_t const txdr = LMIC.dndr;

src/lmic/lmic_kr920.c

@@ -223,14 +223,6 @@ ostime_t LMICkr920_nextJoinState(void) {
 }
 #endif // !DISABLE_JOIN
 
-// // txDone handling for FSK.
-// void
-// LMICkr920_txDoneFSK(ostime_t delay, osjobcb_t func) {
-//         LMIC.rxtime = LMIC.txend + delay - PRERX_FSK*us2osticksRound(160);
-//         LMIC.rxsyms = RXLEN_FSK;
-//         os_setTimedCallback(&LMIC.osjob, LMIC.rxtime - RX_RAMPUP, func);
-// }
-
 // set the Rx1 dndr, rps.
 void LMICkr920_setRx1Params(void) {
     u1_t const txdr = LMIC.dndr;