Configuration Commands (32-62)

These commands manage flight controller settings including battery, modes, features, and hardware configuration.

MSP_BATTERY_CONFIG (32)

Query battery monitoring configuration.

Response

Offset	Type	Field	Description
0	U8	vbat_min_cell	Minimum cell voltage × 10
1	U8	vbat_max_cell	Maximum cell voltage × 10
2	U8	vbat_warning_cell	Warning voltage × 10
3-4	U16	capacity	Battery capacity in mAh
5	U8	voltage_source	0=none, 1=ADC, 2=ESC
6	U8	current_source	0=none, 1=ADC, 2=ESC, 3=MSP

#[derive(Debug, Clone, Copy)]
#[repr(C, packed)]
pub struct MspBatteryConfig {
    pub vbat_min_cell: u8,      // Minimum cell voltage × 10 (e.g., 33 = 3.3V)
    pub vbat_max_cell: u8,      // Maximum cell voltage × 10 (e.g., 42 = 4.2V)
    pub vbat_warning_cell: u8,  // Warning voltage × 10 (e.g., 35 = 3.5V)
    pub capacity: u16,          // mAh
    pub voltage_source: u8,
    pub current_source: u8,
}

impl MspBatteryConfig {
    pub const COMMAND: u8 = 32;

    pub fn from_bytes(data: &[u8]) -> Option<Self> {
        if data.len() < 7 {
            return None;
        }
        Some(MspBatteryConfig {
            vbat_min_cell: data[0],
            vbat_max_cell: data[1],
            vbat_warning_cell: data[2],
            capacity: u16::from_le_bytes([data[3], data[4]]),
            voltage_source: data[5],
            current_source: data[6],
        })
    }

    pub fn min_cell_voltage(&self) -> f32 {
        self.vbat_min_cell as f32 / 10.0
    }

    pub fn max_cell_voltage(&self) -> f32 {
        self.vbat_max_cell as f32 / 10.0
    }
}

MSP_MODE_RANGES (34)

Query flight mode activation ranges. Each mode can be activated based on an auxiliary channel position.

Response

Array of mode range entries (40 entries typical):

Offset	Type	Field	Description
0	U8	box_id	Flight mode box ID
1	U8	aux_channel	Aux channel index (0 = AUX1)
2	U8	range_start	Start position (0-47, step=25, offset=900)
3	U8	range_end	End position (0-47)

Range Calculation

PWM range: 900-2100 µs
Step size: 25 µs
Value 0 = 900 µs, Value 48 = 2100 µs
PWM = 900 + (value × 25)

#[derive(Debug, Clone, Copy)]
pub struct MspModeRange {
    pub box_id: u8,
    pub aux_channel: u8,
    pub range_start: u8,
    pub range_end: u8,
}

impl MspModeRange {
    pub fn from_bytes(data: &[u8]) -> Option<Self> {
        if data.len() < 4 {
            return None;
        }
        Some(MspModeRange {
            box_id: data[0],
            aux_channel: data[1],
            range_start: data[2],
            range_end: data[3],
        })
    }

    /// Convert range value to PWM microseconds
    pub fn range_to_pwm(value: u8) -> u16 {
        900 + (value as u16 * 25)
    }

    pub fn start_pwm(&self) -> u16 {
        Self::range_to_pwm(self.range_start)
    }

    pub fn end_pwm(&self) -> u16 {
        Self::range_to_pwm(self.range_end)
    }

    /// Check if a PWM value activates this mode
    pub fn is_active(&self, pwm: u16) -> bool {
        pwm >= self.start_pwm() && pwm <= self.end_pwm()
    }
}

/// Parse all mode ranges from response
pub fn parse_mode_ranges(data: &[u8]) -> Vec<MspModeRange> {
    data.chunks(4)
        .filter_map(MspModeRange::from_bytes)
        .filter(|r| r.box_id != 0 || r.aux_channel != 0)  // Skip empty slots
        .collect()
}

MSP_FEATURE_CONFIG (36)

Query enabled features as a bitmask.

Response

Offset	Type	Field	Description
0-3	U32	features	Feature flags bitmask

Feature Flags

bitflags::bitflags! {
    #[derive(Debug, Clone, Copy)]
    pub struct Features: u32 {
        const RX_PPM = 1 << 0;
        const INFLIGHT_ACC_CAL = 1 << 2;
        const RX_SERIAL = 1 << 3;
        const MOTOR_STOP = 1 << 4;
        const SERVO_TILT = 1 << 5;
        const SOFTSERIAL = 1 << 6;
        const GPS = 1 << 7;
        const RANGEFINDER = 1 << 9;
        const TELEMETRY = 1 << 10;
        const THREE_D = 1 << 12;
        const RX_PARALLEL_PWM = 1 << 13;
        const RX_MSP = 1 << 14;
        const RSSI_ADC = 1 << 15;
        const LED_STRIP = 1 << 16;
        const DISPLAY = 1 << 17;
        const OSD = 1 << 18;
        const CHANNEL_FORWARDING = 1 << 20;
        const TRANSPONDER = 1 << 21;
        const AIRMODE = 1 << 22;
        const RX_SPI = 1 << 25;
        const ESC_SENSOR = 1 << 27;
        const ANTI_GRAVITY = 1 << 28;
    }
}

impl Features {
    pub fn from_bytes(data: &[u8]) -> Option<Self> {
        if data.len() < 4 {
            return None;
        }
        let bits = u32::from_le_bytes([data[0], data[1], data[2], data[3]]);
        Some(Features::from_bits_truncate(bits))
    }
}

MSP_RX_CONFIG (44)

Query receiver configuration.

Response

Offset	Type	Field	Description
0	U8	serialrx_provider	Serial RX protocol
1-2	U16	max_check	Max valid channel value
3-4	U16	mid_rc	Center stick value
5-6	U16	min_check	Min valid channel value
7	U8	spektrum_sat_bind	Spektrum satellite bind
8-9	U16	rx_min_usec	Minimum valid PWM
10-11	U16	rx_max_usec	Maximum valid PWM
12	U8	rc_interpolation	Interpolation type
13	U8	rc_interpolation_interval	Interval in ms
14-15	U16	airmode_start_throttle	Airmode activation throttle
16	U8	rx_spi_protocol	SPI RX protocol
17-20	U32	rx_spi_id	SPI RX ID
21	U8	rx_spi_rf_channel_count	SPI RF channels
22	U8	fpv_cam_angle_degrees	FPV camera angle
23	U8	rc_smoothing	Smoothing config

Serial RX Protocols

Value	Protocol
0	SPEK1024
1	SPEK2048
2	SBUS
3	SUMD
4	SUMH
5	XB-B
6	XB-B-RJ01
7	IBUS
8	JETIEXBUS
9	CRSF
10	SRXL
11	CUSTOM
12	FPORT
13	SRXL2
14	GHST

#[derive(Debug, Clone, Copy, PartialEq)]
#[repr(u8)]
pub enum SerialRxProtocol {
    Spektrum1024 = 0,
    Spektrum2048 = 1,
    Sbus = 2,
    Sumd = 3,
    Sumh = 4,
    XBusB = 5,
    XBusBRJ01 = 6,
    Ibus = 7,
    JetiExBus = 8,
    Crsf = 9,
    Srxl = 10,
    Custom = 11,
    Fport = 12,
    Srxl2 = 13,
    Ghst = 14,
}

#[derive(Debug, Clone)]
pub struct MspRxConfig {
    pub serialrx_provider: u8,
    pub max_check: u16,
    pub mid_rc: u16,
    pub min_check: u16,
    pub rx_min_usec: u16,
    pub rx_max_usec: u16,
    pub rc_interpolation: u8,
    pub rc_interpolation_interval: u8,
}

impl MspRxConfig {
    pub const COMMAND: u8 = 44;

    pub fn from_bytes(data: &[u8]) -> Option<Self> {
        if data.len() < 14 {
            return None;
        }
        Some(MspRxConfig {
            serialrx_provider: data[0],
            max_check: u16::from_le_bytes([data[1], data[2]]),
            mid_rc: u16::from_le_bytes([data[3], data[4]]),
            min_check: u16::from_le_bytes([data[5], data[6]]),
            rx_min_usec: u16::from_le_bytes([data[8], data[9]]),
            rx_max_usec: u16::from_le_bytes([data[10], data[11]]),
            rc_interpolation: data[12],
            rc_interpolation_interval: data[13],
        })
    }
}

MSP_CF_SERIAL_CONFIG (54)

Query serial port configuration.

Response

Array of port configurations:

Offset	Type	Field	Description
0	U8	identifier	Port identifier
1-2	U16	function_mask	Function flags
3	U8	msp_baud	MSP baud rate index
4	U8	gps_baud	GPS baud rate index
5	U8	telemetry_baud	Telemetry baud rate
6	U8	blackbox_baud	Blackbox baud rate

Port Identifiers

Value	Port
0	USB VCP
1	UART1
2	UART2
3	UART3
4	UART4
5	UART5
6	UART6
20	SOFTSERIAL1
21	SOFTSERIAL2

Function Flags

bitflags::bitflags! {
    #[derive(Debug, Clone, Copy)]
    pub struct SerialPortFunction: u16 {
        const NONE = 0;
        const MSP = 1 << 0;
        const GPS = 1 << 1;
        const TELEMETRY_FRSKY = 1 << 2;
        const TELEMETRY_HOTT = 1 << 3;
        const TELEMETRY_LTM = 1 << 4;
        const TELEMETRY_SMARTPORT = 1 << 5;
        const RX_SERIAL = 1 << 6;
        const BLACKBOX = 1 << 7;
        const TELEMETRY_MAVLINK = 1 << 9;
        const ESC_SENSOR = 1 << 10;
        const VTX_SMARTAUDIO = 1 << 11;
        const TELEMETRY_IBUS = 1 << 12;
        const VTX_TRAMP = 1 << 13;
        const RCDEVICE = 1 << 14;
        const LIDAR_TF = 1 << 15;
    }
}

#[derive(Debug, Clone)]
pub struct SerialPortConfig {
    pub identifier: u8,
    pub function_mask: SerialPortFunction,
    pub msp_baud_index: u8,
    pub gps_baud_index: u8,
    pub telemetry_baud_index: u8,
    pub blackbox_baud_index: u8,
}

impl SerialPortConfig {
    pub fn from_bytes(data: &[u8]) -> Option<Self> {
        if data.len() < 7 {
            return None;
        }
        Some(SerialPortConfig {
            identifier: data[0],
            function_mask: SerialPortFunction::from_bits_truncate(
                u16::from_le_bytes([data[1], data[2]])
            ),
            msp_baud_index: data[3],
            gps_baud_index: data[4],
            telemetry_baud_index: data[5],
            blackbox_baud_index: data[6],
        })
    }
}

MSP_ARMING_CONFIG (61)

Query arming configuration.

Response

Offset	Type	Field	Description
0	U8	auto_disarm_delay	Auto-disarm timeout (seconds)
1	U8	disarm_kill_switch	Disarm switch behavior
2	U8	small_angle	Max arm angle (degrees)

#[derive(Debug, Clone, Copy)]
pub struct MspArmingConfig {
    pub auto_disarm_delay: u8,    // Seconds, 0 = disabled
    pub disarm_kill_switch: u8,   // 0 = normal, 1 = kill switch
    pub small_angle: u8,          // Max arming angle in degrees
}

impl MspArmingConfig {
    pub const COMMAND: u8 = 61;

    pub fn from_bytes(data: &[u8]) -> Option<Self> {
        if data.len() < 3 {
            return None;
        }
        Some(MspArmingConfig {
            auto_disarm_delay: data[0],
            disarm_kill_switch: data[1],
            small_angle: data[2],
        })
    }
}

MSP_SET Commands

MSP_SET_FEATURE_CONFIG (37)

Set feature flags.

pub fn build_set_feature_request(features: Features) -> Vec<u8> {
    const MSP_SET_FEATURE_CONFIG: u8 = 37;
    let bits = features.bits();
    let payload = bits.to_le_bytes();

    let size = 4u8;
    let mut checksum = size ^ MSP_SET_FEATURE_CONFIG;
    for b in &payload {
        checksum ^= b;
    }

    vec![
        b'$', b'M', b'<',
        size,
        MSP_SET_FEATURE_CONFIG,
        payload[0], payload[1], payload[2], payload[3],
        checksum,
    ]
}

MSP_SET_ARMING_CONFIG (62)

Set arming configuration.

pub fn build_set_arming_config(
    auto_disarm_delay: u8,
    disarm_kill_switch: u8,
    small_angle: u8,
) -> Vec<u8> {
    const MSP_SET_ARMING_CONFIG: u8 = 62;
    let payload = [auto_disarm_delay, disarm_kill_switch, small_angle];

    let size = 3u8;
    let mut checksum = size ^ MSP_SET_ARMING_CONFIG;
    for b in &payload {
        checksum ^= b;
    }

    vec![
        b'$', b'M', b'<',
        size,
        MSP_SET_ARMING_CONFIG,
        payload[0], payload[1], payload[2],
        checksum,
    ]
}

Important Notes

Configuration changes require EEPROM write: After modifying settings, send MSP_EEPROM_WRITE (250) to persist changes.
Some changes require reboot: Feature flags and serial port changes typically require a reboot (MSP_REBOOT command 68).
Verify before write: Always read the current configuration, modify only needed fields, and write back the complete structure.

MSP_BATTERY_CONFIG (32)​

Response​

MSP_MODE_RANGES (34)​

Response​

Range Calculation​

MSP_FEATURE_CONFIG (36)​

Response​

Feature Flags​

MSP_RX_CONFIG (44)​

Response​

Serial RX Protocols​

MSP_CF_SERIAL_CONFIG (54)​

Response​

Port Identifiers​

Function Flags​

MSP_ARMING_CONFIG (61)​

Response​

MSP_SET Commands​

MSP_SET_FEATURE_CONFIG (37)​

MSP_SET_ARMING_CONFIG (62)​

Important Notes​

MSP_BATTERY_CONFIG (32)

Response

MSP_MODE_RANGES (34)

Response

Range Calculation

MSP_FEATURE_CONFIG (36)

Response

Feature Flags

MSP_RX_CONFIG (44)

Response

Serial RX Protocols

MSP_CF_SERIAL_CONFIG (54)

Response

Port Identifiers

Function Flags

MSP_ARMING_CONFIG (61)

Response

MSP_SET Commands

MSP_SET_FEATURE_CONFIG (37)

MSP_SET_ARMING_CONFIG (62)

Important Notes