From 4e2d9abaf7f0500a877c6fbee86a56cf553137d5 Mon Sep 17 00:00:00 2001
From: Florent Kermarrec <florent@enjoy-digital.fr>
Date: Fri, 27 Apr 2018 14:32:03 +0200
Subject: [PATCH] firmware/ad9154: combine analog and digital delay of hmc7043
 for sysref scan

---
 artiq/firmware/libboard_artiq/ad9154.rs      | 34 ++++++++++----------
 artiq/firmware/libboard_artiq/hmc830_7043.rs | 14 +++++---
 2 files changed, 26 insertions(+), 22 deletions(-)

diff --git a/artiq/firmware/libboard_artiq/ad9154.rs b/artiq/firmware/libboard_artiq/ad9154.rs
index 2f9bbd86c..48f4cdcc1 100644
--- a/artiq/firmware/libboard_artiq/ad9154.rs
+++ b/artiq/firmware/libboard_artiq/ad9154.rs
@@ -1,6 +1,6 @@
 use board::{csr, clock};
 use ad9154_reg;
-use hmc830_7043::{hmc7043};
+use hmc830_7043::hmc7043;
 
 fn spi_setup(dacno: u8) {
     unsafe {
@@ -611,39 +611,39 @@ fn dac_cfg_retry(dacno: u8) -> Result<(), &'static str> {
 fn dac_sysref_cfg(dacno: u8) {
     let mut sync_error: u16 = 0;
     let mut sync_error_last: u16 = 0;
-    let mut cphase_min_found: bool = false;
-    let mut cphase_min: u8 = 0;
-    let mut cphase_max_found: bool = false;
-    let mut cphase_max: u8 = 0;
-    let mut cphase_opt: u8 = 0;
+    let mut phase_min_found: bool = false;
+    let mut phase_min: u16 = 0;
+    let mut phase_max_found: bool = false;
+    let mut phase_max: u16 = 0;
+    let mut phase_opt: u16 = 0;
 
     info!("AD9154-{} SYSREF scan/conf...", dacno);
-    for cphase in 0..32 {
-        hmc7043::cfg_dac_sysref(dacno, 0, cphase);
+    for phase in 0..512 {
+        hmc7043::cfg_dac_sysref(dacno, phase);
         clock::spin_us(10000);
         spi_setup(dacno);
         sync_error = ((read(ad9154_reg::SYNC_CURRERR_L) as u16) |
                      ((read(ad9154_reg::SYNC_CURRERR_H) as u16) << 8))
                      & 0x1ff;
-        info!("  cphase: {}, sync error: {}", cphase, sync_error);
+        info!("  phase: {}, sync error: {}", phase, sync_error);
         if sync_error != 0 {
-            if cphase_min_found {
+            if phase_min_found {
                 if sync_error != sync_error_last {
-                    cphase_max_found = true;
-                    cphase_max = cphase - 1;
+                    phase_max_found = true;
+                    phase_max = phase - 1;
                     break;
                 }
             } else {
-                cphase_min_found = true;
-                cphase_min = cphase;
+                phase_min_found = true;
+                phase_min = phase;
             }
         }
         sync_error_last = sync_error;
     }
 
-    cphase_opt = cphase_min + (cphase_max-cphase_min)/2;
-    info!("  cphase min: {}, cphase max: {}, cphase opt: {}", cphase_min, cphase_max, cphase_opt);
-    hmc7043::cfg_dac_sysref(dacno, 0, cphase_opt);
+    phase_opt = phase_min + (phase_max-phase_min)/2;
+    info!("  phase min: {}, phase max: {}, phase opt: {}", phase_min, phase_max, phase_opt);
+    hmc7043::cfg_dac_sysref(dacno, phase_opt);
 }
 
 pub fn init() -> Result<(), &'static str> {
diff --git a/artiq/firmware/libboard_artiq/hmc830_7043.rs b/artiq/firmware/libboard_artiq/hmc830_7043.rs
index b1e5d9201..fef3c8236 100644
--- a/artiq/firmware/libboard_artiq/hmc830_7043.rs
+++ b/artiq/firmware/libboard_artiq/hmc830_7043.rs
@@ -250,14 +250,18 @@ pub mod hmc7043 {
         Ok(())
     }
 
-    pub fn cfg_dac_sysref(dacno: u8, aphase: u8, cphase: u8) {
+    pub fn cfg_dac_sysref(dacno: u8, phase: u16) {
         spi_setup();
+        /*  Analog delay resolution: 25ps
+         *  Digital delay resolution: 1/2 input clock cycle = 416ps for 1.2GHz
+         *  16*25ps = 400ps: limit analog delay to 16 steps instead of 32.
+         */
         if dacno == 0 {
-            write(0x00D5, aphase);
-            write(0x00D6, cphase);
+            write(0x00d5, (phase & 0xf) as u8);
+            write(0x00d6, ((phase >> 4) & 0x1f) as u8);
         } else if dacno == 1 {
-            write(0x00E9, aphase);
-            write(0x00EA, cphase);
+            write(0x00e9, (phase & 0xf) as u8);
+            write(0x00ea, ((phase >> 4) & 0x1f) as u8);
         } else {
             unimplemented!();
         }