Mbed OS Reference | LoRaRadio.h Source File

 /**
  * Copyright (c) 2017, Arm Limited and affiliates.
  * SPDX-License-Identifier: Apache-2.0
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 #ifndef LORARADIO_H_
 #define LORARADIO_H_
 
 /** @addtogroup LoRaWAN
  * Parent class for a LoRa radio driver
  *  @{
  */
 
 #include "platform/Callback.h"
 #include "PinNames.h"
 
 /**
  * Structure to hold RF controls for LoRa Radio.
  * SX1276 have an extra control for the crystal (used in DISCO-L072CZ).
  * A subset of these pins may be used by the driver in accordance with the physical
  * implementation.
  */
 typedef struct {
     /** TX latch switch pin.
      * Exact operation is implementation specific.
      */
     PinName rf_switch_ctl1;
 
     /** RX latch switch pin.
      * Exact operation is implementation specific.
      */
     PinName rf_switch_ctl2;
 
     /** TX control pin for transceiver packaged as a module.
      * Exact operation is implementation specific.
      */
     PinName txctl;
 
     /** RX control pin for transceiver packaged as a module.
      * Exact operation is implementation specific.
      */
     PinName rxctl;
 
     /** Transceiver switch pin.
      * Exact operation is implementation specific. One of the polarities of the
      * pin may drive the transceiver in either TX or RX mode.
      */
     PinName ant_switch;
 
     /** Power amplifier control pin.
      * Exact operation is implementation specific. If defined,
      * controls the operation of an external power amplifier.
      */
     PinName pwr_amp_ctl;
 
     /** TCXO crystal control pin.
      * Exact operation is implementation specific.
      */
     PinName tcxo;
 } rf_ctrls;
 
 /** Radio driver internal state.
  * Helps identify current state of the transceiver.
  */
 typedef enum radio_state {
     /** IDLE state.
      * Radio is in idle state.
      */
     RF_IDLE = 0,
 
     /** RX state.
      * Radio is receiving.
      */
     RF_RX_RUNNING,
 
     /** TX state.
      * Radio is transmitting.
      */
     RF_TX_RUNNING,
 
     /** CAD state.
      * Radio is detecting channel activity.
      */
     RF_CAD,
 } radio_state_t;
 
 /** Type of modem.
  *  [LORA/FSK]
  */
 typedef enum modem_type {
     /** FSK operation mode.
      * Radio is using FSK modulation.
      */
     MODEM_FSK = 0,
 
     /** LoRa operation mode.
      * Radio is using LoRa modulation.
      */
     MODEM_LORA
 } radio_modems_t;
 
 /** FSK modem parameters.
  * Parameters encompassing FSK modulation.
  */
 typedef struct radio_fsk_settings {
     /**
      * Transmit power.
      */
     int8_t   power;
 
     /**
      * Frequency deviation.
      */
     uint32_t f_dev;
 
     /**
      * Modulation bandwidth.
      */
     uint32_t bandwidth;
 
     /**
      * Automated frequency correction bandwidth.
      */
     uint32_t bandwidth_afc;
 
     /**
      * Data rate (SF).
      */
     uint32_t datarate;
 
     /**
      * Expected preamble length.
      */
     uint16_t preamble_len;
 
     /**
      * This flag turns on if the TX data size is fixed.
      */
     bool fix_len;
 
     /**
      * Size of outgoing data.
      */
     uint8_t  payload_len;
 
     /**
      * Turn CRC on/off.
      */
     bool crc_on;
 
     /** @deprecated
      * Does not apply to FSK. Will be removed.
      */
     bool iq_inverted;
 
     /**
      * Turn continuous reception mode (such as Class C mode) on/off.
      */
     bool rx_continuous;
 
     /**
      * Timeout value in milliseconds (ms) after which the radio driver reports
      * a timeout if the radio was unable to transmit.
      */
     uint32_t tx_timeout;
 
     /**
      * Timeout value in symbols (symb) after which the radio driver reports a timeout
      * if the radio did not receive a Preamble.
      */
     uint32_t rx_single_timeout;
 } radio_fsk_settings_t;
 
 /** FSK packet handle.
  * Contains information about an FSK packet and various metadata.
  */
 typedef struct radio_fsk_packet_handler {
     /**
      * Set to true (1) when a Preamble is detected, otherwise false (0).
      */
     uint8_t preamble_detected;
 
     /**
      * Set to true (1) when a SyncWord is detected, otherwise false (0).
      */
     uint8_t sync_word_detected;
 
     /**
      * Storage for RSSI value of the received signal.
      */
     int16_t rssi_value;
 
     /**
      * Automated frequency correction value.
      */
     int32_t afc_value;
 
     /**
      * LNA gain value (dbm).
      */
     uint8_t rx_gain;
 
     /**
      * Size of the received data in bytes.
      */
     uint16_t size;
 
     /**
      * Keeps track of number of bytes already read from the RX FIFO.
      */
     uint16_t nb_bytes;
 
     /**
      * Stores the FIFO threshold value.
      */
     uint8_t fifo_thresh;
 
     /**
      * Defines the size of a chunk of outgoing buffer written to
      * the FIFO at a unit time. For example, if the size of the data exceeds the FIFO
      * limit, a certain sized chunk is written to the FIFO. Later, a FIFO-level
      * interrupt enables writing of the remaining data to the FIFO chunk by chunk until
      * transmission is complete.
      */
     uint8_t chunk_size;
 } radio_fsk_packet_handler_t;
 
 /** LoRa modem parameters.
  * Parameters encompassing LoRa modulation.
  */
 typedef struct radio_lora_settings {
     /**
      * Transmit power.
      */
     int8_t power;
 
     /**
      * Modulation bandwidth.
      */
     uint32_t bandwidth;
 
     /**
      * Data rate (SF).
      */
     uint32_t datarate;
 
     /**
      * Turn low data rate optimization on/off.
      */
     bool low_datarate_optimize;
 
     /**
      * Error correction code rate.
      */
     uint8_t coderate;
 
     /**
      * Preamble length in symbols.
      */
     uint16_t preamble_len;
 
     /**
      * Set to true if the outgoing payload length is fixed.
      */
     bool fix_len;
 
     /**
      * Size of outgoing payload.
      */
     uint8_t payload_len;
 
     /**
      * Turn CRC on/off.
      */
     bool crc_on;
 
     /**
      * Turn frequency hopping on/off.
      */
     bool freq_hop_on;
 
     /**
      * Number of symbols between two frequency hops.
      */
     uint8_t hop_period;
 
     /**
      * Turn IQ inversion on/off. Usually, the end device sends an IQ inverted
      * signal, and the base stations do not invert. We recommended sending an
      * IQ inverted signal from the device side, so any transmissions from the
      * base stations do not interfere with end device transmission.
      */
     bool iq_inverted;
 
     /**
      * Turn continuous reception mode (such as in Class C) on/off.
      */
     bool rx_continuous;
 
     /**
      * Timeout in milliseconds (ms) after which the radio driver reports an error
      * if the radio was unable to transmit.
      */
     uint32_t tx_timeout;
 
     /**
      * Change the network mode to Public or Private.
      */
     bool public_network;
 } radio_lora_settings_t;
 
 /** LoRa packet
  * Contains information about a LoRa packet.
  */
 typedef struct radio_lora_packet_handler {
     /**
      * Signal-to-noise ratio of a received packet.
      */
     int8_t snr_value;
 
     /**
      * RSSI value in dBm for the received packet.
      */
     int16_t rssi_value;
 
     /**
      * Size of the transmitted or received packet.
      */
     uint8_t size;
 } radio_lora_packet_handler_t;
 
 /** Global radio settings.
  * Contains settings for the overall transceiver operation.
  */
 typedef struct radio_settings {
     /**
      * Current state of the radio, such as RF_IDLE.
      */
     uint8_t                     state;
 
     /**
      * Current modem operation, such as MODEM_LORA.
      */
     uint8_t                     modem;
 
     /**
      * Current channel of operation.
      */
     uint32_t                    channel;
 
     /**
      * Settings for FSK modem part.
      */
     radio_fsk_settings_t        fsk;
 
     /**
      * FSK packet and meta data.
      */
     radio_fsk_packet_handler_t  fsk_packet_handler;
 
     /**
      * Settings for LoRa modem part.
      */
     radio_lora_settings_t       lora;
 
     /**
      * LoRa packet and metadata.
      */
     radio_lora_packet_handler_t lora_packet_handler;
 } radio_settings_t;
 
 /** Reporting functions for upper layers.
  * The radio driver reports various vital events to the upper controlling layers
  * using callback functions provided by the upper layers at the initialization
  * phase.
  */
 typedef struct radio_events {
     /**
      * Callback when Transmission is done.
      */
     mbed::Callback<void()> tx_done;
 
     /**
      * Callback when Transmission is timed out.
      */
     mbed::Callback<void()> tx_timeout;
 
     /**
      * Rx Done callback prototype.
      *
      *  @param payload Received buffer pointer.
      *  @param size    Received buffer size.
      *  @param rssi    RSSI value computed while receiving the frame [dBm].
      *  @param snr     Raw SNR value given by the radio hardware.
      *                     FSK : N/A (set to 0)
      *                     LoRa: SNR value in dB
      */
     mbed::Callback<void(const uint8_t *payload, uint16_t size, int16_t rssi, int8_t snr)> rx_done;
 
     /**
      * Callback when Reception is timed out.
      */
     mbed::Callback<void()> rx_timeout;
 
     /**
      * Callback when Reception ends up in error.
      */
     mbed::Callback<void()> rx_error;
 
     /**
      * FHSS Change Channel callback prototype.
      *
      *  @param current_channel   The index number of the current channel.
      */
     mbed::Callback<void(uint8_t current_channel)> fhss_change_channel;
 
     /**
      * CAD Done callback prototype.
      *
      *  @param channel_busy    True, if Channel activity detected.
      */
     mbed::Callback<void(bool channel_busy)> cad_done;
 } radio_events_t;
 
 /**
  * Interface for the radios, containing the main functions that a radio needs, and five callback functions.
  */
 class LoRaRadio {
 
 public:
 
     /**
      * Registers radio events with the Mbed LoRaWAN stack and undergoes initialization steps, if any.
      *
      *  @param events Contains driver callback functions.
      */
     virtual void init_radio(radio_events_t *events) = 0;
 
     /**
      * Resets the radio module.
      */
     virtual void radio_reset() = 0;
 
     /**
      *  Put the RF module in sleep mode.
      */
     virtual void sleep(void) = 0;
 
     /**
      *  Sets the radio to standby mode.
      */
     virtual void standby(void) = 0;
 
     /**
      *  Sets reception parameters.
      *
      *  @param modem         The radio modem [0: FSK, 1: LoRa].
      *  @param bandwidth     Sets the bandwidth.
      *                          FSK : >= 2600 and <= 250000 Hz
      *                          LoRa: [0: 125 kHz, 1: 250 kHz,
      *                                 2: 500 kHz, 3: Reserved]
      *  @param datarate      Sets the datarate.
      *                          FSK : 600..300000 bits/s
      *                          LoRa: [6: 64, 7: 128, 8: 256, 9: 512,
      *                                10: 1024, 11: 2048, 12: 4096  chips]
      *  @param coderate      Sets the coding rate (LoRa only).
      *                          FSK : N/A ( set to 0 )
      *                          LoRa: [1: 4/5, 2: 4/6, 3: 4/7, 4: 4/8]
      *  @param bandwidth_afc Sets the AFC bandwidth (FSK only).
      *                          FSK : >= 2600 and <= 250000 Hz
      *                          LoRa: N/A (set to 0)
      *  @param preamble_len  Sets the preamble length (LoRa only).
      *                          FSK : N/A (set to 0)
      *                          LoRa: Length in symbols (the hardware adds four more symbols).
      *  @param symb_timeout  Sets the RxSingle timeout value.
      *                          FSK : Timeout number of bytes
      *                          LoRa: Timeout in symbols
      *  @param fix_len        Fixed length packets [0: variable, 1: fixed].
      *  @param payload_len   Sets the payload length when fixed length is used.
      *  @param crc_on        Enables/disables CRC [0: OFF, 1: ON].
      *  @param freq_hop_on   Enables/disables intra-packet frequency hopping [0: OFF, 1: ON] (LoRa only).
      *  @param hop_period    The number of symbols bewteen each hop (LoRa only).
      *  @param iq_inverted   Inverts the IQ signals (LoRa only).
      *                          FSK : N/A (set to 0)
      *                          LoRa: [0: not inverted, 1: inverted]
      *  @param rx_continuous Sets the reception to continuous mode.
      *                          [false: single mode, true: continuous mode]
      */
     virtual void set_rx_config(radio_modems_t modem, uint32_t bandwidth,
                                uint32_t datarate, uint8_t coderate,
                                uint32_t bandwidth_afc, uint16_t preamble_len,
                                uint16_t symb_timeout, bool fix_len,
                                uint8_t payload_len,
                                bool crc_on, bool freq_hop_on, uint8_t hop_period,
                                bool iq_inverted, bool rx_continuous) = 0;
 
     /**
      *  Sets the transmission parameters.
      *
      *  @param modem         The radio modem [0: FSK, 1: LoRa].
      *  @param power         Sets the output power [dBm].
      *  @param fdev          Sets the frequency deviation (FSK only).
      *                          FSK : [Hz]
      *                          LoRa: 0
      *  @param bandwidth     Sets the bandwidth (LoRa only).
      *                          FSK : 0
      *                          LoRa: [0: 125 kHz, 1: 250 kHz,
      *                                 2: 500 kHz, 3: Reserved]
      *  @param datarate      Sets the datarate.
      *                          FSK : 600..300000 bits/s
      *                          LoRa: [6: 64, 7: 128, 8: 256, 9: 512,
      *                                10: 1024, 11: 2048, 12: 4096  chips]
      *  @param coderate      Sets the coding rate (LoRa only).
      *                          FSK : N/A ( set to 0 )
      *                          LoRa: [1: 4/5, 2: 4/6, 3: 4/7, 4: 4/8]
      *  @param preamble_len  Sets the preamble length.
      *  @param fix_len       Fixed length packets [0: variable, 1: fixed].
      *  @param crc_on        Enables/disables CRC [0: OFF, 1: ON].
      *  @param freq_hop_on   Enables/disables intra-packet frequency hopping [0: OFF, 1: ON] (LoRa only).
      *  @param hop_period    The number of symbols between each hop (LoRa only).
      *  @param iq_inverted   Inverts IQ signals (LoRa only)
      *                          FSK : N/A (set to 0).
      *                          LoRa: [0: not inverted, 1: inverted]
      *  @param timeout       The transmission timeout [ms].
      */
     virtual void set_tx_config(radio_modems_t modem, int8_t power, uint32_t fdev,
                                uint32_t bandwidth, uint32_t datarate,
                                uint8_t coderate, uint16_t preamble_len,
                                bool fix_len, bool crc_on, bool freq_hop_on,
                                uint8_t hop_period, bool iq_inverted, uint32_t timeout) = 0;
 
     /**
      *  Sends the packet.
      *
      *  Prepares the packet to be sent and sets the radio to transmission mode.
      *
      *  @param buffer        A pointer to the buffer.
      *  @param size          The buffer size.
      */
     virtual void send(uint8_t *buffer, uint8_t size) = 0;
 
     /**
      *  Sets the radio to reception mode.
      *
      *  To configure the receiver, use the `set_rx_config()` API.
      */
     virtual void receive(void) = 0;
 
     /**
      *  Sets the carrier frequency.
      *
      *  @param freq          Channel RF frequency.
      */
     virtual void set_channel(uint32_t freq) = 0;
 
     /**
      *  Generates a 32 bit random value based on RSSI readings.
      *
      *  \remark This function sets the radio in LoRa modem mode and disables all interrupts.
      *          After calling this function, either `Radio.SetRxConfig` or
      *         `Radio.SetTxConfig` functions must be called.
      *
      *  @return             A 32 bit random value.
      */
     virtual uint32_t random(void) = 0;
 
     /**
      *  Gets the radio status.
      *
      *  @return              The current radio status.
      */
     virtual uint8_t get_status(void) = 0;
 
     /**
      *  Sets the maximum payload length.
      *
      *  @param modem         The radio modem [0: FSK, 1: LoRa].
      *  @param max           The maximum payload length in bytes.
      */
     virtual void set_max_payload_length(radio_modems_t modem, uint8_t max) = 0;
 
     /**
      *  Sets the network to public or private.
      *
      *  Updates the sync byte. Applies to LoRa modem only.
      *
      *  @param enable        If true, enables a public network.
      */
     virtual void set_public_network(bool enable) = 0;
 
     /**
      *  Computes the packet time on air for the given payload.
      *
      *  \remark This can only be called after `SetRxConfig` or `SetTxConfig`.
      *
      *  @param modem         The radio modem [0: FSK, 1: LoRa].
      *  @param pkt_len       The packet payload length.
      *  @return              The computed `airTime` for the given packet payload length.
      */
     virtual uint32_t time_on_air(radio_modems_t modem, uint8_t pkt_len) = 0;
 
     /**
      * Performs carrier sensing.
      *
      * Checks for a certain time if the RSSI is above a given threshold.
      * This threshold determines whether or not there is a transmission on
      * the channel already.
      *
      * @param modem                     The type of radio modem.
      * @param freq                      The carrier frequency.
      * @param rssi_threshold            The threshold value of RSSI.
      * @param max_carrier_sense_time    The time set for sensing the channel (ms).
      *
      * @return                          True if there is no active transmission
      *                                  in the channel, otherwise false.
      */
     virtual bool perform_carrier_sense(radio_modems_t modem,
                                        uint32_t freq,
                                        int16_t rssi_threshold,
                                        uint32_t max_carrier_sense_time) = 0;
 
     /**
      *  Sets the radio to CAD mode.
      *
      */
     virtual void start_cad(void) = 0;
 
     /**
      *  Checks whether the given RF is in range.
      *
      *  @param frequency       The frequency to check.
      */
     virtual bool check_rf_frequency(uint32_t frequency) = 0;
 
     /** Sets the radio to continuous wave transmission mode.
      *
      *  @param freq          The RF frequency of the channel.
      *  @param power         The output power [dBm].
      *  @param time          The transmission mode timeout [s].
      */
     virtual void set_tx_continuous_wave(uint32_t freq, int8_t power, uint16_t time) = 0;
 
     /**
      * Acquires exclusive access to this radio.
      */
     virtual void lock(void) = 0;
 
     /**
      * Releases exclusive access to this radio.
      */
     virtual void unlock(void) = 0;
 };
 
 #endif // LORARADIO_H_
 /** @}*/
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