cu_wt901/
lib.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
use bincode::de::Decoder;
use bincode::enc::Encoder;
use bincode::error::{DecodeError, EncodeError};
use bincode::{Decode, Encode};
use cu29::clock::RobotClock;
use cu29::config::ComponentConfig;
use cu29::cutask::{CuMsg, CuSrcTask, CuTaskLifecycle, Freezable};
use cu29::{output_msg, CuResult};
use embedded_hal::i2c::I2c;
use linux_embedded_hal::{I2CError, I2cdev};
use std::fmt::Display;
use uom::si::acceleration::{meter_per_second_squared, standard_gravity};
use uom::si::angle::{degree, radian};
use uom::si::angular_velocity::{degree_per_second, radian_per_second};
use uom::si::f32::Acceleration;
use uom::si::f32::Angle;
use uom::si::f32::AngularVelocity;
use uom::si::f32::MagneticFluxDensity;
use uom::si::magnetic_flux_density::{nanotesla, tesla};

// FIXME: remove.
const I2C_BUS: &str = "/dev/i2c-9";
const WT901_I2C_ADDRESS: u8 = 0x50;

#[repr(u8)]
#[derive(Debug, Clone, Copy)]
enum Registers {
    // Accelerometer addresses
    AccX = 0x34,
    AccY = 0x35,
    AccZ = 0x36,

    // Gyroscope addresses
    GyroX = 0x37,
    GyroY = 0x38,
    GyroZ = 0x39,

    // Magnetometer addresses
    MagX = 0x3A,
    MagY = 0x3B,
    MagZ = 0x3C,

    // Orientation addresses
    Roll = 0x3D,
    Pitch = 0x3E,
    Yaw = 0x3F,
}

impl Registers {
    fn offset(&self) -> usize {
        ((*self as u8 - Registers::AccX as u8) * 2) as usize
    }
}

use cu29_log_derive::debug;
use cu29_traits::CuError;
use serde::de::{Deserialize, Deserializer};
use serde::ser::{Serialize, SerializeStruct, Serializer};
use uom::fmt::DisplayStyle::Abbreviation;

pub struct WT901 {
    i2c: Box<dyn I2c<Error = I2CError>>,
}

#[derive(Default, Debug)]
pub struct PositionalReadings {
    acc_x: Acceleration,
    acc_y: Acceleration,
    acc_z: Acceleration,
    gyro_x: AngularVelocity,
    gyro_y: AngularVelocity,
    gyro_z: AngularVelocity,
    mag_x: MagneticFluxDensity,
    mag_y: MagneticFluxDensity,
    mag_z: MagneticFluxDensity,
    roll: Angle,
    pitch: Angle,
    yaw: Angle,
}

impl Display for PositionalReadings {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        let acc_style = Acceleration::format_args(standard_gravity, Abbreviation);
        let angv_style = AngularVelocity::format_args(degree_per_second, Abbreviation);
        let mag_style = MagneticFluxDensity::format_args(nanotesla, Abbreviation);
        let angle_style = Angle::format_args(degree, Abbreviation);

        write!(
            f,
            "acc_x: {}, acc_y: {}, acc_z: {}\n gyro_x: {}, gyro_y: {}, gyro_z: {}\nmag_x: {}, mag_y: {}, mag_z: {}\nroll: {}, pitch: {}, yaw: {}",
            acc_style.with(self.acc_x), acc_style.with(self.acc_y), acc_style.with(self.acc_z),
            angv_style.with(self.gyro_x), angv_style.with(self.gyro_y), angv_style.with(self.gyro_z),
            mag_style.with(self.mag_x), mag_style.with(self.mag_y), mag_style.with(self.mag_z),
            angle_style.with(self.roll), angle_style.with(self.pitch), angle_style.with(self.yaw)
        )
    }
}

impl Serialize for PositionalReadings {
    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
        let mut s = serializer.serialize_struct("PositionalReadings", 12)?;
        s.serialize_field("acc_x", &self.acc_x.value)?;
        s.serialize_field("acc_y", &self.acc_y.value)?;
        s.serialize_field("acc_z", &self.acc_z.value)?;
        s.serialize_field("gyro_x", &self.gyro_x.value)?;
        s.serialize_field("gyro_y", &self.gyro_y.value)?;
        s.serialize_field("gyro_z", &self.gyro_z.value)?;
        s.serialize_field("mag_x", &self.mag_x.value)?;
        s.serialize_field("mag_y", &self.mag_y.value)?;
        s.serialize_field("mag_z", &self.mag_z.value)?;
        s.serialize_field("roll", &self.roll.value)?;
        s.serialize_field("pitch", &self.pitch.value)?;
        s.serialize_field("yaw", &self.yaw.value)?;
        s.end()
    }
}

impl<'de> Deserialize<'de> for PositionalReadings {
    fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
        let values = <[f32; 12]>::deserialize(deserializer)?;
        Ok(PositionalReadings {
            acc_x: Acceleration::new::<standard_gravity>(values[0]),
            acc_y: Acceleration::new::<standard_gravity>(values[1]),
            acc_z: Acceleration::new::<standard_gravity>(values[2]),
            gyro_x: AngularVelocity::new::<degree_per_second>(values[3]),
            gyro_y: AngularVelocity::new::<degree_per_second>(values[4]),
            gyro_z: AngularVelocity::new::<degree_per_second>(values[5]),
            mag_x: MagneticFluxDensity::new::<nanotesla>(values[6]),
            mag_y: MagneticFluxDensity::new::<nanotesla>(values[7]),
            mag_z: MagneticFluxDensity::new::<nanotesla>(values[8]),
            roll: Angle::new::<degree>(values[9]),
            pitch: Angle::new::<degree>(values[10]),
            yaw: Angle::new::<degree>(values[11]),
        })
    }
}

impl Encode for PositionalReadings {
    fn encode<E: Encoder>(&self, encoder: &mut E) -> Result<(), EncodeError> {
        // Encode in natural SI units
        self.acc_x.value.encode(encoder)?;
        self.acc_y.value.encode(encoder)?;
        self.acc_z.value.encode(encoder)?;
        self.gyro_x.value.encode(encoder)?;
        self.gyro_y.value.encode(encoder)?;
        self.gyro_z.value.encode(encoder)?;
        self.mag_x.value.encode(encoder)?;
        self.mag_y.value.encode(encoder)?;
        self.mag_z.value.encode(encoder)?;
        self.roll.value.encode(encoder)?;
        self.pitch.value.encode(encoder)?;
        self.yaw.value.encode(encoder)?;
        Ok(())
    }
}

impl Decode for PositionalReadings {
    fn decode<D: Decoder>(decoder: &mut D) -> Result<Self, DecodeError> {
        Ok(PositionalReadings {
            // Decode back from the natural SI units
            acc_x: Acceleration::new::<meter_per_second_squared>(f32::decode(decoder)?),
            acc_y: Acceleration::new::<meter_per_second_squared>(f32::decode(decoder)?),
            acc_z: Acceleration::new::<meter_per_second_squared>(f32::decode(decoder)?),
            gyro_x: AngularVelocity::new::<radian_per_second>(f32::decode(decoder)?),
            gyro_y: AngularVelocity::new::<radian_per_second>(f32::decode(decoder)?),
            gyro_z: AngularVelocity::new::<radian_per_second>(f32::decode(decoder)?),
            mag_x: MagneticFluxDensity::new::<tesla>(f32::decode(decoder)?),
            mag_y: MagneticFluxDensity::new::<tesla>(f32::decode(decoder)?),
            mag_z: MagneticFluxDensity::new::<tesla>(f32::decode(decoder)?),
            roll: Angle::new::<radian>(f32::decode(decoder)?),
            pitch: Angle::new::<radian>(f32::decode(decoder)?),
            yaw: Angle::new::<radian>(f32::decode(decoder)?),
        })
    }
}

// Number of registers to read in one go
const REGISTER_SPAN_SIZE: usize = ((Registers::Yaw as u8 - Registers::AccX as u8) * 2 + 2) as usize;

impl WT901 {
    fn bulk_position_read(
        &mut self,
        pr: &mut PositionalReadings,
    ) -> Result<(), i2cdev::linux::LinuxI2CError> {
        debug!("Trying to read i2c");
        let mut buf = [0u8; REGISTER_SPAN_SIZE];
        self.i2c
            .write_read(WT901_I2C_ADDRESS, &[Registers::AccX as u8], &mut buf)
            .expect("Error reading WT901");

        pr.acc_x = convert_acc(get_vec_i16(&buf, Registers::AccX.offset()));
        pr.acc_y = convert_acc(get_vec_i16(&buf, Registers::AccY.offset()));
        pr.acc_z = convert_acc(get_vec_i16(&buf, Registers::AccZ.offset()));
        pr.gyro_x = convert_ang_vel(get_vec_i16(&buf, Registers::GyroX.offset()));
        pr.gyro_y = convert_ang_vel(get_vec_i16(&buf, Registers::GyroY.offset()));
        pr.gyro_z = convert_ang_vel(get_vec_i16(&buf, Registers::GyroZ.offset()));
        pr.mag_x = convert_mag(get_vec_i16(&buf, Registers::MagX.offset()));
        pr.mag_y = convert_mag(get_vec_i16(&buf, Registers::MagY.offset()));
        pr.mag_z = convert_mag(get_vec_i16(&buf, Registers::MagZ.offset()));
        pr.roll = convert_angle(get_vec_i16(&buf, Registers::Roll.offset()));
        pr.pitch = convert_angle(get_vec_i16(&buf, Registers::Pitch.offset()));
        pr.yaw = convert_angle(get_vec_i16(&buf, Registers::Yaw.offset()));
        println!("{}", pr);
        Ok(())
    }
}

impl Freezable for WT901 {
    // WT901 has no internal state, we can leave the default implementation.
}

impl CuTaskLifecycle for WT901 {
    fn new(_config: Option<&ComponentConfig>) -> CuResult<Self>
    where
        Self: Sized,
    {
        debug!("Opening {}... ", I2C_BUS);
        let i2cdev = I2cdev::new(I2C_BUS).unwrap();
        debug!("{} opened.", I2C_BUS);
        Ok(WT901 {
            i2c: Box::new(i2cdev),
        })
    }
}

impl<'cl> CuSrcTask<'cl> for WT901 {
    type Output = output_msg!('cl, PositionalReadings);

    fn process(&mut self, _clock: &RobotClock, new_msg: Self::Output) -> CuResult<()> {
        let mut pos = PositionalReadings::default();
        self.bulk_position_read(&mut pos)
            .map_err(|e| CuError::from(format!("Error reading WT901: {:?}", e)))?;
        new_msg.set_payload(pos);
        Ok(())
    }
}

/// Get a u16 value out of a u8 buffer
#[inline]
#[allow(dead_code)]
fn get_vec_u16(buf: &[u8], offset: usize) -> u16 {
    u16::from_le_bytes([buf[offset], buf[offset + 1]])
}

/// Get a u16 value out of a u8 buffer
#[inline]
fn get_vec_i16(buf: &[u8], offset: usize) -> i16 {
    i16::from_le_bytes([buf[offset], buf[offset + 1]])
}

fn convert_acc(acc: i16) -> Acceleration {
    // the scale is from 0 to 16g
    let acc = acc as f32 / 32768.0 * 16.0;
    Acceleration::new::<standard_gravity>(acc)
}

fn convert_ang_vel(angv: i16) -> AngularVelocity {
    // the scale is from 0 to 2000 deg/s
    let acc = (angv as f32 / 32768.0) * 2000.0;
    AngularVelocity::new::<degree_per_second>(acc)
}

fn convert_mag(mag: i16) -> MagneticFluxDensity {
    // the resolution is 8.333nT/LSB
    let mag = (mag as f32 / 32768.0) * 8.333;
    MagneticFluxDensity::new::<nanotesla>(mag)
}

fn convert_angle(angle: i16) -> Angle {
    let angle = angle as f32 / 32768.0 * 180.0;
    Angle::new::<degree>(angle)
}