feat(tdma): setup of tdmamanager

Author: ToKine0

acoustic_modem/include/tdma_manager.hpp

@@ -6,6 +6,7 @@
  */
 
 struct TDMAConfig{
+    // should be two with just two nodes
     uint8_t num_slots;
     uint8_t my_slot;
     std::chrono::seconds slot=std::chrono::seconds(25);
@@ -15,7 +16,7 @@ struct TDMAConfig{
 
 class TDMAManager{
     public:
-    TDMAManager(TDMAConfig config);
+    TDMAManager(TDMAConfig config) : cfg(config){}
 
     // who is transmitting?
     uint8_t current_slot(std::chrono::steady_clock::time_point now);

acoustic_modem/src/tdma_manager.cpp

@@ -0,0 +1,31 @@
+#include "tdma_manager.hpp"
+
+// return type can be changed
+uint8_t TDMAManager::current_slot(std::chrono::steady_clock::time_point now){
+    auto cycle=cfg.num_slots*cfg.slot;
+    auto elapsed=now-cfg.t0;
+    // how far are we in the cycle
+    auto time_cycle=elapsed%cycle;
+    uint8_t slot_i= time_cycle/cfg.slot;
+    return slot_i
+}
+
+bool TDMAManager::tx_allowed(std::chrono::steady_clock::time_point now){
+    if(current_slot(now)!=cfg.my_slot){
+        return false;
+    }
+    auto cycle=cfg.num_slots*cfg.slot;
+    auto elapsed=now-cfg.t0;
+    // how far are we in the cycle
+    auto time_cycle=elapsed%cycle;
+    uint8_t slot_i= time_cycle/cfg.slot;
+    auto offset_in_slot=time_cycle%cfg.slot;
+
+    if(offset_in_slot<cfg.guard){
+        return false;
+    }
+    if(offset_in_slot>(cfg.slot-cfg.guard)){
+        return false;
+    }
+    return true;
+}