nscope 1.0.0

Communication with nScope devices
Documentation 
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

/***************************************************************************************************
 *
 *  nLabs, LLC
 *  https://nscope.org
 *  Copyright(c) 2020. All Rights Reserved
 *
 *  This file is part of the nScope API
 *
 **************************************************************************************************/

use std::error::Error;
use std::sync::{Arc, mpsc, RwLock};
use std::sync::mpsc::{Receiver, Sender};

use log::trace;

use super::AnalogInput;
use super::Command;
use super::commands::ScopeCommand;
use super::Nscope;
use super::Trigger;

/// Voltage information from all open channels at a given time
#[derive(Debug, Default, Clone)]
pub struct Sample {
    pub time_since_start: f64,
    pub data: [Option<f64>; Sample::num_channels() as usize],
}

impl Sample {
    pub const fn num_channels() -> u32 { 4 }

    pub fn clear(&mut self) {
        self.data = [None; Sample::num_channels() as usize];
    }
}

#[derive(Debug)]
pub(super) struct DataRequest {
    pub channels: [AnalogInput; 4],
    pub sample_rate_hz: f64,
    pub remaining_samples: Arc<RwLock<u32>>,
    pub trigger: Trigger,
    pub sender: Sender<Sample>,
    pub stop_recv: Receiver<()>,
}

/// Handle to an ongoing data sweep, holds received data from nScope
#[derive(Debug)]
pub struct SweepHandle {
    pub receiver: Receiver<Sample>,
    samples_remaining: Arc<RwLock<u32>>,
    stop_send: Sender<()>,
}

#[derive(Debug)]
pub(super) struct StopRequest {}

impl Nscope {
    pub fn request(&self, sample_rate_hz: f64, number_of_samples: u32, trigger: Option<Trigger>) -> SweepHandle {
        let (tx, rx) = mpsc::channel::<Sample>();
        let (stop_send, stop_recv) = mpsc::channel::<()>();

        let remaining_samples = Arc::new(RwLock::new(number_of_samples));
        let command = Command::RequestData(DataRequest {
            channels: [self.ch1, self.ch2, self.ch3, self.ch4],
            sample_rate_hz,
            remaining_samples: remaining_samples.clone(),
            trigger: trigger.unwrap_or_default(),
            sender: tx,
            stop_recv,
        });

        self.command_tx.send(command).unwrap();

        SweepHandle {
            receiver: rx,
            samples_remaining: remaining_samples,
            stop_send,
        }
    }
}

impl SweepHandle {
    pub fn remaining_samples(&self) -> u32 {
        *self.samples_remaining.read().unwrap()
    }

    pub fn stop(&self) {
        self.stop_send.send(()).ok();
    }
}

impl ScopeCommand for DataRequest {
    fn fill_tx_buffer(&self, usb_buf: &mut [u8; 65]) -> Result<(), Box<dyn Error>> {
        usb_buf[1] = 0x08;

        let num_channels_on = self.channels.iter().filter(|&ch| ch.is_on).count();


        let samples_between_records: u32 = match num_channels_on {
            0 => { return Err("No scope channels are on".into()); }
            1 => { (4_000_000.0 / self.sample_rate_hz) as u32 }
            2 => { (2_000_000.0 / self.sample_rate_hz) as u32 }
            3 | 4 => { (1_000_000.0 / self.sample_rate_hz) as u32 }
            _ => { return Err("Unexpected number of channels are on".into()); }
        };

        let total_samples = *self.remaining_samples.read().unwrap();
        if samples_between_records < 250 && total_samples * num_channels_on as u32 > 3200 {
            return Err("Data not recordable".into());
        }


        usb_buf[3..=6].copy_from_slice(&samples_between_records.to_le_bytes());
        usb_buf[7..=10].copy_from_slice(&total_samples.to_le_bytes());
        trace!("Requesting {} samples with {} samples between records", total_samples, samples_between_records);

        if self.trigger.is_enabled {
            usb_buf[11] = (self.trigger.source_channel | (self.trigger.trigger_type.value() << 2)) as u8;

            if !(0..4usize).contains(&self.trigger.source_channel) {
                return Err("Invalid trigger channel".into());
            }
            let trigger_channel = self.channels[self.trigger.source_channel];
            let trigger_level = trigger_channel.measurement_from_voltage(self.trigger.trigger_level);
            if !(105..3990).contains(&trigger_level) {
                return Err("Trigger level is outside operating range of the channel".into());
            }
            let trigger_level = trigger_level as u16;
            usb_buf[11] |= ((trigger_level & 0x000F) << 4) as u8;
            usb_buf[12] = ((trigger_level & 0x0FF0) >> 4) as u8;

            let trigger_delay: u16 = match num_channels_on {
                1 => { 4 * self.trigger.trigger_delay_us / samples_between_records }
                2 => { 2 * self.trigger.trigger_delay_us / samples_between_records }
                3..=4 => { self.trigger.trigger_delay_us / samples_between_records }
                _ => { 1 }
            } as u16;
            usb_buf[13..=14].copy_from_slice(&trigger_delay.to_le_bytes());
        } else {
            usb_buf[11..=14].fill(0);
        }


        for (i, ch) in self.channels.iter().enumerate() {
            if ch.is_on {
                usb_buf[15 + i] = ch.gain_setting;
                usb_buf[19 + i] = ch.offset_setting;
            } else {
                usb_buf[15 + i] = 0xFF;
            }
        }


        Ok(())
    }

    fn handle_rx(&self, usb_buf: &[u8; 64]) {
        let number_received_samples = usb_buf[3] as u32;

        {
            let mut remaining_samples = self.remaining_samples.write().unwrap();
            *remaining_samples -= number_received_samples;
            trace!("Received {} samples, {} samples remaining", number_received_samples, remaining_samples);
        }


        let mut total_parsed_readings: usize = 0;

        for _ in 0..number_received_samples {
            let mut sample = Sample {
                time_since_start: 0.0,
                data: [None; 4],
            };

            for (i, ch) in self.channels.iter().enumerate() {
                if ch.is_on {
                    let byte = 4 + total_parsed_readings / 2 * 3;

                    let adc_data = match total_parsed_readings & 1 {
                        0 => usb_buf[byte] as u16 | ((usb_buf[byte + 1] & 0xF) as u16) << 8,
                        1 => usb_buf[byte + 1] as u16 >> 4 | (usb_buf[byte + 2] as u16) << 4,
                        _ => panic!("Unexpected behavior of odd/even bitmask")
                    };

                    trace!("Ch{}: ADCData: {} Vi: {}", i+1, adc_data, ch.voltage_from_measurement(adc_data));
                    sample.data[i] = Some(ch.voltage_from_measurement(adc_data));
                    total_parsed_readings += 1;
                }
            }

            self.sender.send(sample).unwrap();
        }
    }

    fn is_finished(&self) -> bool {
        *self.remaining_samples.read().unwrap() == 0
    }
}

impl ScopeCommand for StopRequest {
    fn fill_tx_buffer(&self, usb_buf: &mut [u8; 65]) -> Result<(), Box<dyn Error>> {
        usb_buf[1] = 0x05;
        Ok(())
    }
    fn handle_rx(&self, _usb_buf: &[u8; 64]) {}
    fn is_finished(&self) -> bool { true }
}