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wrpll: add more diagnostics in firmware and adapt to recent gateware changes

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hartytp 2020-10-06 17:21:39 +01:00 committed by Sebastien Bourdeauducq
parent 7d7be6e711
commit e6ff2ddc32
1 changed files with 96 additions and 36 deletions
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132
artiq/firmware/libboard_artiq/wrpll.rs
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@ -266,6 +266,9 @@ mod si549 {
Ok(())
}
// Si549 digital frequency trim ("all-digital PLL" register)
// ∆ f_out = adpll * 0.0001164e-6 (0.1164 ppb/lsb)
// max trim range is +- 950 ppm
pub fn set_adpll(dcxo: i2c::Dcxo, adpll: i32) -> Result<(), &'static str> {
write(dcxo, 231, adpll as u8)?;
write(dcxo, 232, (adpll >> 8) as u8)?;
@ -282,6 +285,20 @@ mod si549 {
}
}
// to do: load from gateware config
const DDMTD_COUNTER_N: u32 = 15;
const DDMTD_COUNTER_M: u32 = (1 << DDMTD_COUNTER_N);
const F_SYS: f64 = csr::CONFIG_CLOCK_FREQUENCY as f64;
const F_MAIN: f64 = 125.0e6;
const F_HELPER: f64 = F_MAIN * DDMTD_COUNTER_M as f64 / (DDMTD_COUNTER_M + 1) as f64;
const F_BEAT: f64 = F_MAIN - F_HELPER;
const TIME_STEP: f32 = 1./F_BEAT as f32;
fn ddmtd_tag_to_s(mu: f32) -> f32 {
return (mu as f32)*TIME_STEP;
}
fn get_frequencies() -> (u32, u32, u32) {
unsafe {
csr::wrpll::frequency_counter_update_en_write(1);
@ -304,24 +321,58 @@ fn log_frequencies() -> (u32, u32, u32) {
(f_helper, f_main, f_cdr)
}
fn get_ddmtd_main_tag() -> u16 {
fn get_tags() -> (i32, i32, u16, u16) {
unsafe {
csr::wrpll::ddmtd_main_arm_write(1);
while csr::wrpll::ddmtd_main_arm_read() != 0 {}
csr::wrpll::ddmtd_main_tag_read()
csr::wrpll::tag_arm_write(1);
while csr::wrpll::tag_arm_read() != 0 {}
let main_diff = csr::wrpll::main_diff_tag_read() as i32;
let helper_diff = csr::wrpll::helper_diff_tag_read() as i32;
let ref_tag = csr::wrpll::ref_tag_read();
let main_tag = csr::wrpll::main_tag_read();
(main_diff, helper_diff, ref_tag, main_tag)
}
}
fn get_ddmtd_helper_tag() -> u16 {
unsafe {
csr::wrpll::ddmtd_helper_arm_write(1);
while csr::wrpll::ddmtd_helper_arm_read() != 0 {}
csr::wrpll::ddmtd_helper_tag_read()
fn print_tags() {
const NUM_TAGS: usize = 30;
let mut main_diffs = [0; NUM_TAGS]; // input to main loop filter
let mut helper_diffs = [0; NUM_TAGS]; // input to helper loop filter
let mut ref_tags = [0; NUM_TAGS];
let mut main_tags = [0; NUM_TAGS];
let mut jitter = [0 as f32; NUM_TAGS];
for i in 0..NUM_TAGS {
let (main_diff, helper_diff, ref_tag, main_tag) = get_tags();
main_diffs[i] = main_diff;
helper_diffs[i] = helper_diff;
ref_tags[i] = ref_tag;
main_tags[i] = main_tag;
}
info!("DDMTD ref tags: {:?}", ref_tags);
info!("DDMTD main tags: {:?}", main_tags);
info!("DDMTD main diffs: {:?}", main_diffs);
info!("DDMTD helper diffs: {:?}", helper_diffs);
// look at the difference between the main DCXO and reference...
let t0 = main_diffs[0];
main_diffs.iter_mut().for_each(|x| *x -= t0);
// crude estimate of the max difference across our sample set (assumes no unwrapping issues...)
let delta = main_diffs[main_diffs.len()-1] as f32 / (main_diffs.len()-1) as f32;
info!("detla: {:?} tags", delta);
let delta_f: f32 = delta/DDMTD_COUNTER_M as f32 * F_BEAT as f32;
info!("MAIN <-> ref frequency difference: {:?} Hz ({:?} ppm)", delta_f, delta_f/F_HELPER as f32 * 1e6);
jitter.iter_mut().enumerate().for_each(|(i, x)| *x = main_diffs[i] as f32 - delta*(i as f32));
info!("jitter: {:?} tags", jitter);
let var = jitter.iter().map(|x| x*x).fold(0 as f32, |acc, x| acc + x as f32) / NUM_TAGS as f32;
info!("variance: {:?} tags^2", var);
}
pub fn init() {
info!("initializing...");
info!("initializing WR PLL...");
unsafe { csr::wrpll::helper_reset_write(1); }
@ -348,43 +399,29 @@ pub fn init() {
}
pub fn diagnostics() {
info!("WRPLL diagnostics...");
info!("Untrimmed oscillator frequencies:");
log_frequencies();
info!("ADPLL test:");
// +/-10ppm
si549::set_adpll(i2c::Dcxo::Helper, -85911).expect("ADPLL write failed");
si549::set_adpll(i2c::Dcxo::Main, 85911).expect("ADPLL write failed");
info!("Increase helper DCXO frequency by +10ppm (1.25kHz):");
si549::set_adpll(i2c::Dcxo::Helper, 85911).expect("ADPLL write failed");
// to do: add check on frequency?
log_frequencies();
si549::set_adpll(i2c::Dcxo::Helper, 0).expect("ADPLL write failed");
si549::set_adpll(i2c::Dcxo::Main, 0).expect("ADPLL write failed");
let mut tags = [0; 10];
for i in 0..tags.len() {
tags[i] = get_ddmtd_main_tag();
}
info!("DDMTD main tags: {:?}", tags);
}
fn trim_dcxos(f_helper: u32, f_main: u32, f_cdr: u32) -> Result<(i32, i32), &'static str> {
info!("Trimming oscillator frequencies...");
const DCXO_STEP: i64 = (1.0e6/0.0001164) as i64;
const ADPLL_MAX: i64 = (950.0/0.0001164) as i64;
const TIMER_WIDTH: u32 = 23;
const COUNTER_DIV: u32 = 2;
const F_SYS: f64 = csr::CONFIG_CLOCK_FREQUENCY as f64;
#[cfg(rtio_frequency = "125.0")]
const F_MAIN: f64 = 125.0e6;
const F_HELPER: f64 = F_MAIN * ((1 << 15) as f64)/((1<<15) as f64 + 1.0);
// how many counts we expect to measure
const SYS_COUNTS: i64 = (1 << (TIMER_WIDTH - COUNTER_DIV)) as i64;
const EXP_MAIN_COUNTS: i64 = ((SYS_COUNTS as f64) * (F_MAIN/F_SYS)) as i64;
const EXP_HELPER_COUNTS: i64 = ((SYS_COUNTS as f64) * (F_HELPER/F_SYS)) as i64;
info!("after {} sys counts", SYS_COUNTS);
info!("expect {} main/CDR counts", EXP_MAIN_COUNTS);
info!("expect {} helper counts", EXP_HELPER_COUNTS);
// calibrate the SYS clock to the CDR clock and correct the measured counts
// assume frequency errors are small so we can make an additive correction
// positive error means sys clock is too fast
@ -412,13 +449,35 @@ fn trim_dcxos(f_helper: u32, f_main: u32, f_cdr: u32) -> Result<(i32, i32), &'st
Ok((helper_adpll as i32, main_adpll as i32))
}
fn statistics(data: &[u16]) -> (f32, f32) {
let sum = data.iter().fold(0 as u32, |acc, x| acc + *x as u32);
let mean = sum as f32 / data.len() as f32;
let squared_sum = data.iter().fold(0 as u32, |acc, x| acc + (*x as u32).pow(2));
let variance = (squared_sum as f32 / data.len() as f32) - mean;
return (mean, variance)
}
fn select_recovered_clock_int(rc: bool) -> Result<(), &'static str> {
info!("Untrimmed oscillator frequencies:");
let (f_helper, f_main, f_cdr) = log_frequencies();
if rc {
let (helper_adpll, main_adpll) = trim_dcxos(f_helper, f_main, f_cdr)?;
// to do: add assertion on max frequency shift here?
si549::set_adpll(i2c::Dcxo::Helper, helper_adpll).expect("ADPLL write failed");
si549::set_adpll(i2c::Dcxo::Main, main_adpll).expect("ADPLL write failed");
log_frequencies();
clock::spin_us(100_000); // TO DO: remove/reduce!
print_tags();
info!("increasing main DCXO by 1ppm (125Hz):");
si549::set_adpll(i2c::Dcxo::Main, main_adpll + 8591).expect("ADPLL write failed");
clock::spin_us(100_000);
print_tags();
si549::set_adpll(i2c::Dcxo::Main, main_adpll).expect("ADPLL write failed");
unsafe {
csr::wrpll::adpll_offset_helper_write(helper_adpll as u32);
csr::wrpll::adpll_offset_main_write(main_adpll as u32);
@ -431,11 +490,12 @@ fn select_recovered_clock_int(rc: bool) -> Result<(), &'static str> {
clock::spin_us(100_000);
let mut tags = [0; 10];
for i in 0..tags.len() {
tags[i] = get_ddmtd_helper_tag();
}
info!("DDMTD helper tags: {:?}", tags);
print_tags();
// let mut tags = [0; 10];
// for i in 0..tags.len() {
// tags[i] = get_ddmtd_helper_tag();
// }
// info!("DDMTD helper tags: {:?}", tags);
unsafe {
csr::wrpll::filter_reset_write(1);