From ebaf63479d42b8862ebbbe3b42736c233d0d0670 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C4=99drzej=20Boczar?= <jboczar@antmicro.com>
Date: Fri, 16 Apr 2021 15:35:35 +0200
Subject: [PATCH] init/lpddr4: modify pull-down drive strength to improve
 signal quality

---
 litedram/init.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/litedram/init.py b/litedram/init.py
index 4b684c5..dde56a3 100644
--- a/litedram/init.py
+++ b/litedram/init.py
@@ -456,6 +456,7 @@ def get_lpddr4_phy_init_sequence(phy_settings, timing_settings):
     bl = 16
     dq_odt = "RZQ/2"
     ca_odt = "RZQ/2"
+    pull_down_drive_strength = "RZQ/3"
 
     def get_nwr():
         frequency_ranges = [  # Table 28. Frequency Ranges for RL, WL, nWR, and nRTP Settings
@@ -575,7 +576,7 @@ def get_lpddr4_phy_init_sequence(phy_settings, timing_settings):
         (0, 1, 1),
         (1, 1, 0),
         (2, 1, 0),
-        (3, 3, odt_map["RZQ/6"]),
+        (3, 3, odt_map[pull_down_drive_strength]),
         (6, 1, 0),
         (7, 1, 0),
     ])