Add rssi_cal field; make raw-feather adapt automatically to board in use

Author: terrillmoore

examples/raw-feather/raw-feather.ino

@@ -74,14 +74,33 @@ Revision history:
 #define TX_INTERVAL 2000        // milliseconds
 #define RX_RSSI_INTERVAL 100    // milliseconds
 
-// Pin mapping for Adafruit Feather M0 LoRa
+// Pin mapping for Adafruit Feather M0 LoRa, etc.
+#if defined(ARDUINO_SAMD_FEATHER_M0)
 const lmic_pinmap lmic_pins = {
     .nss = 8,
     .rxtx = LMIC_UNUSED_PIN,
     .rst = 4,
     .dio = {3, 6, LMIC_UNUSED_PIN},
+    .rxtx_rx_active = 0,
+    .rssi_cal = 8,              // LBT cal for the Adafruit Feather M0 LoRa, in dB
+    .spi_freq = 8000000,
 };
-
+#elif defined(ARDUINO_CATENA_4551)
+const lmic_pinmap lmic_pins = {
+        .nss = 7,
+        .rxtx = 29,
+        .rst = 8,
+        .dio = { 25,    // DIO0 (IRQ) is D25
+                 26,    // DIO1 is D26
+                 27,    // DIO2 is D27
+               },
+        .rxtx_rx_active = 1,
+        .rssi_cal = 10,
+        .spi_freq = 8000000     // 8MHz
+};
+#else
+# error "Unknown target"
+#endif
 
 // These callbacks are only used in over-the-air activation, so they are
 // left empty here (we cannot leave them out completely unless

src/hal/hal.cpp

@@ -61,6 +61,10 @@ void hal_pin_rst (u1_t val) {
     }
 }
 
+s1_t hal_getRssiCal (void) {
+    return plmic_pins->rssi_cal;
+}
+
 #if !defined(LMIC_USE_INTERRUPTS)
 static void hal_interrupt_init() {
     pinMode(plmic_pins->dio[0], INPUT);

src/hal/hal.h

@@ -12,13 +12,18 @@
 
 static const int NUM_DIO = 3;
 
+// be careful of alignment below.
 struct lmic_pinmap {
-    u1_t nss;
-    u1_t rxtx;
-    u1_t rst;
-    u1_t dio[NUM_DIO];
-    u1_t rxtx_rx_active;
-    u4_t spi_freq;
+    u1_t nss;                   // byte 0: pin for select
+    u1_t rxtx;                  // byte 1: pin for rx/tx control
+    u1_t rst;                   // byte 2: pin for reset
+    u1_t dio[NUM_DIO];          // bytes 3..5: pins for DIO0, DOI1, DIO2
+    // true if we must set rxtx for rx_active, false for tx_active
+    u1_t rxtx_rx_active;        // byte 6: polarity of rxtx active
+    s1_t rssi_cal;              // byte 7: cal in dB -- added to RSSI
+                                //   measured prior to decision.
+                                //   Must include noise guardband!
+    u4_t spi_freq;              // bytes 8..11: SPI freq in Hz.
 };
 
 // Use this for any unused pins.

src/lmic/hal.h

@@ -105,6 +105,11 @@ u1_t hal_checkTimer (u4_t targettime);
  */
 void hal_failed (const char *file, u2_t line);
 
+/*
+ * get the calibration value for radio_rssi
+ */
+s1_t hal_getRssiCal (void);
+
 #ifdef __cplusplus
 } // extern "C"
 #endif

src/lmic/radio.c

@@ -873,6 +873,7 @@ void radio_monitor_rssi(ostime_t nTicks, oslmic_radio_rssi_t *pRssi) {
     } else {
             rssiAdjust = SX127X_RSSI_ADJUST_LF;
     }
+    rssiAdjust += hal_getRssiCal();
 
     // zero the results
     rssiMax = 255;