Output power config values

[rhssk]

Hello,

v3.0.0 introduced a new command for setting output power configuration:

lr1110_modem_driver/src/lr1110_modem_lorawan.h

Lines 1524 to 1536 in 438e621

	/*!
	* @brief This command sets 6 blocks (at most 6 dedicated power levels) of Tx output power configurations: expected
	* power, configured power, PA, Tx parameters and PA ramp time. For the Tx power levels not defined in the 6 levels with
	* this command, the modem always selects automatically the appropriate PA and Tx parameters configurations.
	*
	* @param [in] context Chip implementation context
	* @param [in] output_power_config Tx output power configuration block list, \see
	* lr1110_modem_output_power_config_list_t
	*
	* @returns Operation status
	*/
	lr1110_modem_response_code_t lr1110_modem_set_output_power_config(
	const void* context, const lr1110_modem_output_power_config_list_t output_power_config );

These are the default values of all 6 blocks after start-up:

expected_power: 128
configured_power: 128
pa_sel: 8
pa_supply: 0x00
pa_duty_cycle: 0x08
pa_hp_sel: 0x00
pa_ramp_time: 0x80

They don't match up with the description of lr1110_modem_output_power_config_t:

lr1110_modem_driver/src/lr1110_modem_lorawan.h

Lines 511 to 535 in 438e621

	/*!
	* @brief Output Power Config structure
	*
	* @ref pa_duty_cycle controls the duty cycle of Power Amplifier according to:
	* \f$ dutycycle = 0.2 + 0.04 \times pa_duty_cycle \f$
	* It can be used to adapt the TX multi-band operation using a single-matching network.
	*
	* The allowed duty cycle values for LPA are from 0.2 to 0.48 (by step of 0.04). Therefore possible values for
	* pa_duty_cycle go from 0 to 7.
	*
	* The allowed duty cycle values for HPA go from 0.2 to 0.36 (by step of 0.04). Therefore in this case, the possible
	* values for pa_duty_cycle go from 0 to 4.
	*
	* @ref pa_hp_sel controls the number of slices for HPA according to: \f$ \#slices = pa_hp_sel + 1 \f$
	*/
	typedef struct
	{
	uint8_t expected_power; //!< Expected power in dBm
	uint8_t configured_power; //!< Configured power in dBm
	uint8_t pa_sel; //!< Power Amplifier selection
	lr1110_modem_pa_reg_supply_t pa_supply; //!< Power Amplifier regulator supply source
	uint8_t pa_duty_cycle; //!< Power Amplifier duty cycle (Default 0x04)
	uint8_t pa_hp_sel; //!< Number of slices for HPA (Default 0x07)
	lr1110_modem_ramp_time_t pa_ramp_time; //!< Power amplifier ramp time
	} lr1110_modem_output_power_config_t;

• expected_power and configured_power have unrealistic values (also, shouldn't they be int8_t instead of uint8_t?).
• pa_duty cycle is supposed to only range from 0 to 7 (LPA) or from 0 to 4 (HPA).
• pa_hp_sel should have a default of 0x07.
• pa_ramp_time doesn't match any value in lr1110_modem_ramp_time_t.
• isn't pa_sel supposed to have a value from from lr1110_modem_radio_pa_selection_t?

Also, it's not clear how the modem chooses which of the 6 blocks from lr1110_modem_output_power_config_list_t to use. Are the blocks somehow matched with the configured Tx power offset value (lr1110_modem_set_tx_power_offset ) via the expected_power or configured_power members?

Firmware info for reference:

type: modem
bootloader: hw: 0x22 type: 0xdf fw: 0x6500
functionality: Wi-Fi/GPS/BeiDou
firmware: 1.1.7
LoRaWAN: 1.0.3
driver: 3.0.1

[smtc-bot]

Thank you for your inquiry.

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