wavemeter: config, displacement calibration

Cargo.lock

@@ -1,5 +1,10 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+[[package]]
+name = "argparse"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "autocfg"
 version = "0.1.6"
@@ -14,6 +19,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "noptica-rs"
 version = "0.1.0"
 dependencies = [
+ "argparse 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.99 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.99 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -90,6 +96,7 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [metadata]
+"checksum argparse 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "3f8ebf5827e4ac4fd5946560e6a99776ea73b596d80898f357007317a7141e47"
 "checksum autocfg 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "b671c8fb71b457dd4ae18c4ba1e59aa81793daacc361d82fcd410cef0d491875"
 "checksum itoa 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)" = "501266b7edd0174f8530248f87f99c88fbe60ca4ef3dd486835b8d8d53136f7f"
 "checksum num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "6ba9a427cfca2be13aa6f6403b0b7e7368fe982bfa16fccc450ce74c46cd9b32"

Cargo.toml

@@ -17,3 +17,4 @@ num-traits = "0.2"
 serde = "1.0"
 serde_derive = "1.0"
 serde_json = "1.0"
+argparse = "0.2.2"

src/noptica.rs

@@ -15,9 +15,12 @@ pub struct Dpll {
 }
 
 impl Dpll {
+    pub const TURN: i64 = 0x100000000;  // One turn in DPLL phase units.
+
     pub fn new(ftw_min: i64, ftw_max: i64, ki: i64, kp: i64) -> Dpll {
-        assert!(ftw_min < 0x80000000);
-        assert!(ftw_max < 0x80000000);
+        assert!(ftw_min < Dpll::TURN/2);
+        assert!(ftw_max < Dpll::TURN/2);
+        assert!(Dpll::TURN & (Dpll::TURN - 1) == 0);  // must be a power of 2
         let init_ftw = (ftw_min + ftw_max)/2;
         Dpll {
             ftw_min: ftw_min,
@@ -32,14 +35,14 @@ impl Dpll {
     }
 
     pub fn frequency_to_ftw(frequency: f64, sample_rate: f64) -> i64 {
-        (frequency*(0x100000000i64 as f64)/sample_rate) as i64
+        (frequency*(Dpll::TURN as f64)/sample_rate) as i64
     }
 
     pub fn tick(&mut self, edge: bool) {
-        self.phase = (self.phase + self.ftw) & 0xffffffff;
+        self.phase = (self.phase + self.ftw) & (Dpll::TURN - 1);
         self.phase_unwrapped = self.phase_unwrapped.wrapping_add(self.ftw);
         if edge {
-            let pe = 0x80000000 - self.phase;
+            let pe = Dpll::TURN/2 - self.phase;
             self.integrator = clamp(self.integrator + (pe*self.ki >> 32),
                 self.ftw_min, self.ftw_max);
             self.ftw = clamp(self.integrator + (pe*self.kp >> 32),
@@ -68,7 +71,7 @@ impl PositionTracker {
     pub fn edge(&mut self, phase: i64) -> i64 {
         let phase_diff = phase.wrapping_sub(self.last_phase);
         self.last_phase = phase;
-        self.current_position += 0x100000000 - phase_diff;
+        self.current_position += Dpll::TURN - phase_diff;
         self.current_position
     }
 }

src/wavemeter.rs

@@ -1,3 +1,109 @@
-fn main() {
-    println!("hello world");
+extern crate argparse;
+extern crate num_traits;
+extern crate serde_derive;
+extern crate serde_json;
+
+use argparse::{ArgumentParser, StoreTrue, Store};
+
+use serde_derive::Deserialize;
+
+use std::error::Error;
+use std::fs::File;
+use std::io::BufReader;
+use std::path::Path;
+
+mod noptica;
+
+#[derive(Deserialize, Debug)]
+struct Config {
+    sample_command: String, // Shell command to start the logic analyzer.
+    sample_rate: f64,       // Sample rate of the logic analyzer in Hz.
+
+    // The logic analyzer command must produce a stream of 4-bit nibbles on its
+    // standard output, which are continuously sampled at the nominal sample rate.
+    // Each of the signals below are mapped to one bit within each nibble.
+    bit_ref: u8,            // Bit# for REF signal of the reference laser head (HP 5501B).
+    bit_meas: u8,           // Bit# for displacement measurement detector (HP 10780).
+    bit_input: u8,          // Bit# for input laser interference detector.
+
+    // The REF DPLL locks to the REF output of the reference laser and provides REF phase
+    // information at each sample of the logic analyzer.
+    // ref_min and ref_max are used to initialize the DPLL and clamp its NCO frequency.
+    ref_min: f64,           // Minimum REF frequency in Hz.
+    ref_max: f64,           // Maximum REF frequency in Hz.
+    refpll_ki: i64,         // Integration constant of the DPLL loop filter.
+    refpll_kp: i64,         // Proportionality constant of the DPLL loop filter.
+
+    ref_wavelength: f64,    // Wavelength of the reference laser in m.
+    scan_displacement: f64, // Optical path difference across one scan cycle in m (use -c).
+    scan_frequency: f64,    // Frequency of the scan in Hz.
+    scan_blanking: f64,     // Fraction of the scan period that is blanked at the beginning
+                            // and end of each slope (4 times per scan period).
+}
+
+fn read_config_from_file<P: AsRef<Path>>(path: P) -> Result<Config, Box<dyn Error>> {
+    let file = File::open(path)?;
+    let reader = BufReader::new(file);
+    let u = serde_json::from_reader(reader)?;
+    Ok(u)
+}
+
+fn do_calibrate(config: &Config) {
+    let mut sample_count = 0;
+    let max_sample_count = (config.sample_rate/4.0) as u32;
+    let mut position_min = i64::max_value();
+    let mut position_max = i64::min_value();
+
+    let mut refpll = noptica::Dpll::new(
+        noptica::Dpll::frequency_to_ftw(config.ref_min, config.sample_rate),
+        noptica::Dpll::frequency_to_ftw(config.ref_max, config.sample_rate),
+        config.refpll_ki,
+        config.refpll_kp);
+    let mut position_tracker = noptica::PositionTracker::new();
+
+    noptica::sample(&config.sample_command, |rising, _falling| {
+        refpll.tick(rising & (1 << config.bit_ref) != 0);
+        if rising & (1 << config.bit_meas) != 0 {
+            let position = position_tracker.edge(refpll.get_phase_unwrapped());
+            if position > position_max {
+                position_max = position;
+            }
+            if position < position_min {
+                position_min = position;
+            }
+        }
+
+        sample_count += 1;
+        if sample_count == max_sample_count {
+            println!("{}", ((position_max-position_min) as f64)/(noptica::Dpll::TURN as f64)*config.ref_wavelength);
+            sample_count = 0;
+            position_min = i64::max_value();
+            position_max = i64::min_value();
+        }
+    })
+}
+
+fn do_wavemeter(config: &Config) {
+    println!("TODO {}", config.sample_command);
+}
+
+fn main() {
+    let mut calibrate = false;
+    let mut config_file = "wavemeter.json".to_string();
+    {
+        let mut ap = ArgumentParser::new();
+        ap.refer(&mut calibrate)
+            .add_option(&["-c", "--calibrate"], StoreTrue,
+            "Calibrate scan displacement");
+        ap.refer(&mut config_file)
+            .add_option(&["--config"], Store,
+            "Configuration file");
+        ap.parse_args_or_exit();
+    }
+    let config = read_config_from_file(config_file).unwrap();
+    if calibrate {
+        do_calibrate(&config);
+    } else {
+        do_wavemeter(&config);
+    }
 }

wavemeter.json

@@ -0,0 +1,17 @@
+{
+    "sample_command": "glasgow run logic -V 3.3 --pins-d 0,1,2",
+    "sample_rate": 48e6,
+    "bit_ref": 0,
+    "bit_meas": 1,
+    "bit_input": 2,
+
+    "ref_min": 1.9e6,
+    "ref_max": 2.1e6,
+    "refpll_ki": 4294967,
+    "refpll_kp": 85899345,
+
+    "ref_wavelength": 632.991372e-9,
+    "scan_displacement": 40e-6,
+    "scan_frequency": 50.0,
+    "scan_blanking": 0.05
+}