M-Labs
/
artiq
mirror of https://github.com/m-labs/artiq.git
2
0
Fork 2
Code Issues Projects Releases Wiki Activity

hmc7043: make margin_{minus,plus} consistent with ad9154

This commit is contained in:
Sebastien Bourdeauducq 2018-06-27 17:35:26 +08:00
parent 4bbdd43bdf
commit 7dfd70c502
1 changed files with 6 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
artiq/firmware/libboard_artiq/hmc830_7043.rs
View File

@ -382,24 +382,23 @@ pub mod hmc7043 {
} }
info!(" ...done ({}/{} slips), verifying timing margin", slips0, slips1); info!(" ...done ({}/{} slips), verifying timing margin", slips0, slips1);
let mut margin_plus = None; let mut margin_minus = 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_plus = Some(d); margin_minus = Some(d);
break; break;
} }
} }
// meet setup/hold // meet setup/hold
sysref_offset_fpga(phase_offset); sysref_offset_fpga(phase_offset);
if margin_plus.is_some() { if margin_minus.is_some() {
let margin_plus = margin_plus.unwrap(); let margin_minus = margin_minus.unwrap();
// one phase slip (period of the 1.2GHz input clock) // one phase slip (period of the 1.2GHz input clock)
let period = 2*17; // approximate: 2 digital coarse delay steps let period = 2*17; // approximate: 2 digital coarse delay steps
let margin_minus = if period > margin_plus { period - margin_plus } else { 0 }; let margin_plus = if period > margin_minus { period - margin_minus } else { 0 };
info!(" margin at FPGA: -{} +{}", margin_minus, margin_plus); info!(" margins at FPGA: -{} +{}", margin_minus, margin_plus);
if margin_minus < 10 || margin_plus < 10 { if margin_minus < 10 || margin_plus < 10 {
error!("SYSREF margin at FPGA is too small"); error!("SYSREF margin at FPGA is too small");
} }