From ba908c0b9319c3a12de98f806dd7007369c777cb Mon Sep 17 00:00:00 2001
From: Manuel Bleichenbacher <manuel.bleichenbacher@gmail.com>
Date: Mon, 26 Jul 2021 22:29:20 +0200
Subject: [PATCH] Configue sub-band

---
 include/TheThingsNetwork.h | 14 ++++++++++++++
 include/ttn.h              | 14 ++++++++++++++
 src/ttn.c                  | 11 +++++++++++
 3 files changed, 39 insertions(+)

diff --git a/include/TheThingsNetwork.h b/include/TheThingsNetwork.h
index 64bdd22..1fb0038 100644
--- a/include/TheThingsNetwork.h
+++ b/include/TheThingsNetwork.h
@@ -193,6 +193,20 @@ public:
         ttn_configure_pins(spi_host, nss, rxtx, rst, dio0, dio1);
     }
 
+    /**
+     * @brief Sets the frequency sub-band to be used.
+     * 
+     * For regions with sub-bands (USA, Australia), sets the sub-band to be used for uplink communication.
+     * For other regions, this function has no effect.
+     * 
+     * The sub-band must be set before joining or sending the first message.
+     * 
+     * If not set, it defaults to sub-band 2 as defined by TTN.
+     * 
+     * @param band band (between 1 and 8)
+     */
+    void setSubband(int band) { ttn_set_subband(band); }
+
     /**
      * @brief Sets the credentials needed to activate the device via OTAA, without activating it.
      * 
diff --git a/include/ttn.h b/include/ttn.h
index d8b189d..b419ffa 100644
--- a/include/ttn.h
+++ b/include/ttn.h
@@ -188,6 +188,20 @@ void ttn_reset(void);
  */
 void ttn_configure_pins(spi_host_device_t spi_host, uint8_t nss, uint8_t rxtx, uint8_t rst, uint8_t dio0, uint8_t dio1);
 
+/**
+ * @brief Sets the frequency sub-band to be used.
+ * 
+ * For regions with sub-bands (USA, Australia), sets the sub-band to be used for uplink communication.
+ * For other regions, this function has no effect.
+ * 
+ * The sub-band must be set before joining or sending the first message.
+ * 
+ * If not set, it defaults to sub-band 2 as defined by TTN.
+ * 
+ * @param band band (between 1 and 8)
+ */
+void ttn_set_subband(int band);
+
 /**
  * @brief Sets the credentials needed to activate the device via OTAA, without activating it.
  * 
diff --git a/src/ttn.c b/src/ttn.c
index f78463a..4c017d2 100644
--- a/src/ttn.c
+++ b/src/ttn.c
@@ -60,6 +60,7 @@ static ttn_message_cb message_callback;
 static ttn_waiting_reason_t waiting_reason = TTN_WAITING_NONE;
 static ttn_rf_settings_t last_rf_settings[4];
 static ttn_rx_tx_window_t current_rx_tx_window;
+static int subband = 1;
 
 static bool join_core(void);
 static void event_callback(void* user_data, ev_t event);
@@ -99,6 +100,11 @@ void ttn_configure_pins(spi_host_device_t spi_host, uint8_t nss, uint8_t rxtx, u
     hal_esp32_start_lmic_task();
 }
 
+void ttn_set_subband(int band)
+{
+    subband = band;
+}
+
 void ttn_reset(void)
 {
     hal_esp32_enter_critical_section();
@@ -203,6 +209,11 @@ bool join_core()
     hal_esp32_enter_critical_section();
     xQueueReset(lmic_event_queue);
     waiting_reason = TTN_WAITING_FOR_JOIN;
+
+#if defined(CFG_us915) || defined(CFG_au915)
+    LMIC_selectSubBand(subband - 1);
+#endif
+
     LMIC_startJoining();
     hal_esp32_wake_up();
     hal_esp32_leave_critical_section();