feat: add TX continuous wave mode and update regulator mode handling

inc/llcc68.hpp

@@ -99,7 +99,7 @@ constexpr bool USE_REGULATOR_LDO = false;
 
  TCXO (Temperature Compensated Crystal Oscillator) will be disabled if this is set to true
 */
-constexpr bool USE_XTAL                            = true;
+constexpr bool USE_TXCO                            = false;
 constexpr llcc68::TcxoVoltage DEFAULT_TCXO_VOLTAGE = TcxoVoltage::V_1_6;
 
 using error_t = spi::error_t;
@@ -117,9 +117,7 @@ struct transmit_state_t {
 /**
  * @brief private namespace; Don't use anything in this namespace outside of this file
  */
-namespace details {
-	inline uint32_t __tcxo_delay__;
-}
+namespace details {}
 
 constexpr auto delay_ms = app::utils::delay_ms;
 
@@ -235,7 +233,7 @@ set_buffer_base_address(const uint8_t txBaseAddress = DEFAULT_TX_BUFFER_ADDRESS,
 }
 
 inline Result<Unit, error_t>
-set_regulator_mode(const uint8_t mode) {
+set_regulator_mode(const enum RegulatorMode mode) {
 	const uint8_t data[] = {mode};
 	return spi::write_stream(RADIOLIB_SX126X_CMD_SET_REGULATOR_MODE, data);
 }
@@ -703,6 +701,23 @@ set_cad() {
 	return spi::write_stream(RADIOLIB_SX126X_CMD_SET_CAD, data);
 }
 
+/**
+ * \brief Set the TX continuous wave mode
+ * \note CW
+ */
+inline Result<Unit, error_t>
+set_tx_continuous_wave() {
+	const uint8_t data[] = {spi::SPI_NOP_COMMAND};
+	return spi::write_stream(RADIOLIB_SX126X_CMD_SET_TX_CONTINUOUS_WAVE, data);
+}
+
+inline Result<Unit, error_t>
+set_tx_infinite_preamble() {
+	const uint8_t data[] = {spi::SPI_NOP_COMMAND};
+	return spi::write_stream(RADIOLIB_SX126X_CMD_SET_TX_INFINITE_PREAMBLE, data);
+}
+
+
 /**
  * \brief Set the PA configuration
  * \param pa_duty_cycle paDutyCycle controls the duty cycle (conduction angle) of both PAs (SX1261 and SX1262). The maximum output power, the
@@ -871,16 +886,6 @@ set_output_power(const int8_t power) {
 	return write_register(RADIOLIB_SX126X_REG_OCP_CONFIGURATION, std::span<const uint8_t>{&ocp, 1});
 }
 
-inline Result<Unit, error_t>
-set_regulator_ldo() {
-	return set_regulator_mode(RADIOLIB_SX126X_REGULATOR_LDO);
-}
-
-inline Result<Unit, error_t>
-set_regulator_dc_dc() {
-	return set_regulator_mode(RADIOLIB_SX126X_REGULATOR_DC_DC);
-}
-
 /**
  * \brief checks if BUSY pin is low
  * \return true if BUSY pin is low, false otherwise
@@ -1250,12 +1255,34 @@ static constexpr auto begin = [](const lora_parameters_t &params) -> Result<Unit
 		return ue_t{error_t{error::RADIO_CHIP_NOT_FOUND}};
 	}
 
-	// FIXME
-	// according to https://github.com/nopnop2002/esp-idf-sx126x
-	// we should set TCXO voltage
-	if constexpr (not USE_XTAL) {
-		const auto voltage_     = set_TCXO(DEFAULT_TCXO_VOLTAGE);
-		details::__tcxo_delay__ = *voltage_;
+	/**
+	 * FIXME
+	 *
+	 * The hardware of the SX126x chips can be designed to use either an
+	 * internal LDO or an internal DCDC converter. The DCDC converter provides
+	 * better current savings and will be used in most modules. If there are
+	 * problems to get the SX126x to work, check which HW configuration is used
+	 * and set USE_LDO accordingly.
+	 * If USE_LDO is not set in the hwConfig, DCDC is used as default.
+	 *
+	 * - RADIO_TXEN and RADIO_RXEN are used on eByte E22-900M22S module to
+	 * switch the antenna between RX and TX
+	 * - DIO2 as antenna switch is used in the example Semtech design as default
+	 * and might be used by many modules
+	 * - DIO3 as antenna switch is used by e.g. Insight SIP ISP4520 module which
+	 * integrates a nRF52832 and a SX126x chip
+	 * - Some modules use DIO3 to control the power supply of the TXCO.
+	 * - Some modules use DIO2 to switch the antenna between RX and TX and a
+	 * separate GPIO to power the antenna switch on or off. Switching the
+	 * antenna switch off can reduce the power consumption. The GPIO used to
+	 * control the antenna power is defined as RADIO_RXEN. LOW == power off,
+	 * HIGH == power on.
+	 *
+	 * @sa https://github.com/beegee-tokyo/SX126x-Arduino?tab=readme-ov-file#explanation-for-ldo-and-dcdc-selection
+	 */
+
+	if constexpr (USE_TXCO) {
+		const auto res = set_TCXO(DEFAULT_TCXO_VOLTAGE);
 		APP_RADIO_RETURN_ERR_CTX(res, "set TCXO");
 	}
 	const auto &mod_params    = params.mod_params;
@@ -1274,13 +1301,8 @@ static constexpr auto begin = [](const lora_parameters_t &params) -> Result<Unit
 	res = set_lora_sync_word(params.sync_word);
 	APP_RADIO_RETURN_ERR_CTX(res, "sync word");
 
-	if constexpr (USE_REGULATOR_LDO) {
-		res = set_regulator_ldo();
-		APP_RADIO_RETURN_ERR_CTX(res, "regulator LDO");
-	} else {
-		res = set_regulator_dc_dc();
-		APP_RADIO_RETURN_ERR_CTX(res, "regulator DC-DC");
-	}
+	res = set_regulator_mode(USE_REGULATOR_LDO ? RegulatorMode::REGULATOR_LDO : RegulatorMode::REGULATOR_DC_DC);
+	APP_RADIO_RETURN_ERR_CTX(res, "set regulator mode");
 
 	res = set_current_limit<60.0f>();
 	APP_RADIO_RETURN_ERR_CTX(res, "current limit");

inc/llcc68_definitions.hpp

@@ -27,6 +27,11 @@ enum LoRaBandwidth : uint8_t {
 	BW_500_0 = 0x06,
 };
 
+enum RegulatorMode : uint8_t {
+	REGULATOR_LDO   = RADIOLIB_SX126X_REGULATOR_LDO,
+	REGULATOR_DC_DC = RADIOLIB_SX126X_REGULATOR_DC_DC,
+};
+
 inline const char *to_str(LoRaBandwidth bw) {
 	switch (bw) {
 	case LoRaBandwidth::BW_7_8: