Initial implementation of RSSI based channel picked, not finished yet.

Author: kh4

TX.h

@@ -293,6 +293,9 @@ void checkButton(void)
         return;
       }
       bindRandomize();
+      while(1) {
+        chooseChannelsPerRSSI();
+      }
       txWriteEeprom();
     }
 just_bind:

chpicker.h

@@ -0,0 +1,77 @@
+//OpenLRSng adaptive channel picker
+
+// development only...
+#define CHANNELS_TO_PICK 12
+
+void isort(uint8_t *a, uint8_t n)
+{
+  for (uint8_t i=1; i<n; i++) {
+    for (uint8_t j = i; j> 0 && a[j] < a[j-1]; j--) {
+      uint8_t v = a[j];
+      a[j] = a[j-1];
+      a[j-1] = v;
+    }
+  }
+}
+
+uint8_t chooseChannelsPerRSSI()
+{
+  uint8_t chRSSImax[255];
+  uint8_t picked[CHANNELS_TO_PICK];
+  Serial.println("Entering adaptive channel selection");
+  init_rfm(0);
+  rx_reset();
+  for (uint8_t ch=1; ch<255; ch++) {
+    uint32_t start = millis();
+    rfmSetChannel(ch);
+    delay(1);
+    chRSSImax[ch]=0;
+    while ((millis()-start) < 500) {
+      uint8_t rssi = rfmGetRSSI();
+      if (rssi > chRSSImax[ch]) {
+        chRSSImax[ch] = rssi;
+      }
+    }
+    if (ch&1) {
+      Green_LED_OFF
+      Red_LED_ON
+    } else {
+      Green_LED_ON
+      Red_LED_OFF
+    }
+  }
+
+  for (uint8_t i=0; i < CHANNELS_TO_PICK; i++) {
+    uint8_t lowest, lowestRSSI=255;
+    for (uint8_t ch=1; ch<255; ch++) {
+      if (chRSSImax[ch] < lowestRSSI) {
+        lowestRSSI = chRSSImax[ch];
+        lowest = ch;
+      }
+    }
+    picked[i] = lowest;
+    chRSSImax[lowest]=255;
+    if (lowest>1) {
+      chRSSImax[lowest-1]=255;
+    }
+    if (lowest>2) {
+      chRSSImax[lowest-2]=200;
+    }
+    if (lowest<254) {
+      chRSSImax[lowest+1]=255;
+    }
+    if (lowest<253) {
+      chRSSImax[lowest+2]=200;
+    }
+  }
+
+  isort(picked,CHANNELS_TO_PICK);
+
+  for (uint8_t i=0; i < CHANNELS_TO_PICK; i++) {
+    Serial.print(picked[i]);
+    Serial.print(',');
+  }
+  Serial.println();
+
+  return 1;
+}

openLRSng.ino

@@ -92,6 +92,7 @@
 #include "dialog.h"
 #endif
 #include "frskytx.h"
+#include "chpicker.h"
 #include "TX.h"
 #else
 #include "I2C.h"