diff --git a/top/e31x/e31x.v b/top/e31x/e31x.v
index 7aece61..b303f9a 100644
--- a/top/e31x/e31x.v
+++ b/top/e31x/e31x.v
@@ -849,6 +849,7 @@ module e31x (
     .radio_rst(radio_rst),
     .bus_clk(bus_clk),
     .bus_rst(bus_rst),
+    .clk40(clk40),
 
     // Clocking and PPS Controls/Indicators
     .pps_refclk(pps),
diff --git a/top/e31x/e31x_core.v b/top/e31x/e31x_core.v
index 132129a..6e1d2ed 100644
--- a/top/e31x/e31x_core.v
+++ b/top/e31x/e31x_core.v
@@ -34,6 +34,7 @@ module e31x_core #(
   input wire radio_rst,
   input wire bus_clk,
   input wire bus_rst,
+  input wire clk40,
 
   // Motherboard Registers: AXI lite interface
   input wire                    s_axi_aclk,
@@ -666,7 +667,7 @@ module e31x_core #(
     .PROTOVER(RFNOC_PROTOVER)
   ) rfnoc_image_core_i (
     .chdr_aclk               (bus_clk    ),
-    .ctrl_aclk               (bus_clk    ), //TODO: X310 uses bus_clk_div2. we can also reduce it here.
+    .ctrl_aclk               (clk40      ),
     .core_arst               (bus_rst    ),
     .device_id               (device_id  ),
     .radio_clk               (radio_clk  ),