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hmc7043: stricter check of FPGA SYSREF margin

This commit is contained in:
Sebastien Bourdeauducq 2018-06-21 22:26:49 +08:00
parent e29536351d
commit 07bcdfd91e
1 changed files with 9 additions and 6 deletions
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15
artiq/firmware/libboard_artiq/hmc830_7043.rs
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@ -374,11 +374,11 @@ pub mod hmc7043 {
} }
info!(" ...done ({}/{} slips), verifying timing margin", slips0, slips1); info!(" ...done ({}/{} slips), verifying timing margin", slips0, slips1);
let mut margin = None; let mut margin_plus = None;
for d in 0..phase_offset { for d in 0..phase_offset {
sysref_offset_fpga(phase_offset - d); sysref_offset_fpga(phase_offset - d);
if !sysref_sample() { if !sysref_sample() {
margin = Some(d); margin_plus = Some(d);
break; break;
} }
} }
@ -386,10 +386,13 @@ pub mod hmc7043 {
// meet setup/hold // meet setup/hold
sysref_offset_fpga(phase_offset); sysref_offset_fpga(phase_offset);
if margin.is_some() { if margin_plus.is_some() {
let margin = margin.unwrap(); let margin_plus = margin_plus.unwrap();
info!(" margin at FPGA: {}", margin); // one phase slip (period of the 1.2GHz input clock)
if margin < 10 { let period = 2*17; // approximate: 2 digital coarse delay steps
let margin_minus = if period > margin_plus { period - margin_plus } else { 0 };
info!(" margin at FPGA: -{} +{}", margin_minus, margin_plus);
if margin_minus < 10 || margin_plus < 10 {
error!("SYSREF margin at FPGA is too small"); error!("SYSREF margin at FPGA is too small");
} }
} else { } else {