FHSS: Calculate number of TX slots using defined slot length

deepakvenugopal · May 11, 2018 · ddd7e92 · ddd7e92
1 parent ba98835
commit ddd7e92
Show file tree

Hide file tree

Showing 2 changed files with 9 additions and 4 deletions.
diff --git a/source/Service_Libs/fhss/fhss_ws.c b/source/Service_Libs/fhss/fhss_ws.c
@@ -317,11 +317,16 @@ static bool fhss_ws_check_tx_allowed(fhss_structure_t *fhss_structure)
     if (fhss_structure->ws->is_on_bc_channel == true) {
         return true;
     }
-    uint32_t slot_len_ms = (fhss_structure->ws->fhss_configuration.fhss_broadcast_interval - fhss_structure->ws->fhss_configuration.fhss_bc_dwell_interval) / (WS_NUMBER_OF_TX_SLOTS * 2);
+    uint8_t number_of_tx_slots = ((fhss_structure->ws->fhss_configuration.fhss_broadcast_interval - fhss_structure->ws->fhss_configuration.fhss_bc_dwell_interval) / WS_MAX_TXRX_SLOT_LEN_MS) / 2;
+    // Allow transmission when broadcast interval is very short comparing to MAX slot length
+    if (!number_of_tx_slots) {
+        return true;
+    }
+    uint32_t slot_len_ms = (fhss_structure->ws->fhss_configuration.fhss_broadcast_interval - fhss_structure->ws->fhss_configuration.fhss_bc_dwell_interval) / (number_of_tx_slots * 2);
     uint32_t remaining_time_ms = fhss_structure->platform_functions.fhss_get_remaining_slots(fhss_broadcast_handler, fhss_structure->fhss_api) / 1000;
     uint32_t tx_slot_begin = (fhss_structure->ws->fhss_configuration.fhss_broadcast_interval - fhss_structure->ws->fhss_configuration.fhss_bc_dwell_interval) - (slot_len_ms * (fhss_structure->own_hop & 1));
     uint32_t rx_slot_begin = tx_slot_begin - slot_len_ms;
-    uint8_t n_o_tx_slots = WS_NUMBER_OF_TX_SLOTS;
+    uint8_t n_o_tx_slots = number_of_tx_slots;
 
     while (n_o_tx_slots--) {
         if ((remaining_time_ms <= tx_slot_begin) && (remaining_time_ms > rx_slot_begin)) {

diff --git a/source/Service_Libs/fhss/fhss_ws.h b/source/Service_Libs/fhss/fhss_ws.h
@@ -21,8 +21,8 @@
  * At least 4 channel retries must be used: (Initial channel + WS_NUMBER_OF_CHANNEL_RETRIES) * MAC attempts = (1+4)*4=20 attempts
  */
 #define WS_NUMBER_OF_CHANNEL_RETRIES    4
-//TODO: Make this configurable
-#define WS_NUMBER_OF_TX_SLOTS           2
+//TX/RX slot length in milliseconds
+#define WS_MAX_TXRX_SLOT_LEN_MS         100
 typedef struct fhss_ws fhss_ws_t;
 
 struct fhss_ws