diff --git a/src/gateware/cxp_4r_fmc.py b/src/gateware/cxp_4r_fmc.py
index 6e2718c..a6620b5 100644
--- a/src/gateware/cxp_4r_fmc.py
+++ b/src/gateware/cxp_4r_fmc.py
@@ -29,51 +29,51 @@ fmc_adapter_io = [
     ),
 
     # CoaXPress low speed link
-    ("CXP_LS", 0, Pins("HPC:LA00_CC_P"), IOStandard("LVCMOS25")),
-    ("CXP_LS", 1, Pins("HPC:LA01_CC_N"), IOStandard("LVCMOS25")),
-    ("CXP_LS", 2, Pins("HPC:LA01_CC_P"), IOStandard("LVCMOS25")),
-    ("CXP_LS", 3, Pins("HPC:LA02_N"), IOStandard("LVCMOS25")),
+    ("CXP_LS", 0, Pins("HPC:LA00_CC_P"), IOStandard("LVCMOS33")),
+    ("CXP_LS", 1, Pins("HPC:LA01_CC_N"), IOStandard("LVCMOS33")),
+    ("CXP_LS", 2, Pins("HPC:LA01_CC_P"), IOStandard("LVCMOS33")),
+    ("CXP_LS", 3, Pins("HPC:LA02_N"), IOStandard("LVCMOS33")),
 
     # CoaXPress green and red LED
     ("CXP_LED", 0,
-        Subsignal("green", Pins("HPC:LA11_P"), IOStandard("LVCMOS25")),
-        Subsignal("red", Pins("HPC:LA11_N"), IOStandard("LVCMOS25")),
+        Subsignal("green", Pins("HPC:LA11_P"), IOStandard("LVCMOS33")),
+        Subsignal("red", Pins("HPC:LA11_N"), IOStandard("LVCMOS33")),
     ),
     ("CXP_LED", 1,
-        Subsignal("green", Pins("HPC:LA12_P"), IOStandard("LVCMOS25")),
-        Subsignal("red", Pins("HPC:LA12_N"), IOStandard("LVCMOS25")),
+        Subsignal("green", Pins("HPC:LA12_P"), IOStandard("LVCMOS33")),
+        Subsignal("red", Pins("HPC:LA12_N"), IOStandard("LVCMOS33")),
     ),
     ("CXP_LED", 2,
-        Subsignal("green", Pins("HPC:LA13_P"), IOStandard("LVCMOS25")),
-        Subsignal("red", Pins("HPC:LA13_N"), IOStandard("LVCMOS25")),
+        Subsignal("green", Pins("HPC:LA13_P"), IOStandard("LVCMOS33")),
+        Subsignal("red", Pins("HPC:LA13_N"), IOStandard("LVCMOS33")),
     ),
     ("CXP_LED", 3,
-        Subsignal("green", Pins("HPC:LA14_P"), IOStandard("LVCMOS25")),
-        Subsignal("red", Pins("HPC:LA14_N"), IOStandard("LVCMOS25")),
+        Subsignal("green", Pins("HPC:LA14_P"), IOStandard("LVCMOS33")),
+        Subsignal("red", Pins("HPC:LA14_N"), IOStandard("LVCMOS33")),
     ),
 
     # Power over CoaXPress 
     ("PoCXP", 0,
-        Subsignal("enable", Pins("HPC:LA21_N"), IOStandard("LVCMOS25")),
-        Subsignal("alert", Pins("HPC:LA18_CC_P"), IOStandard("LVCMOS25")),
+        Subsignal("enable", Pins("HPC:LA21_N"), IOStandard("LVCMOS33")),
+        Subsignal("alert", Pins("HPC:LA18_CC_P"), IOStandard("LVCMOS33")),
     ),
     ("PoCXP", 1,
-        Subsignal("enable", Pins("HPC:LA21_P"), IOStandard("LVCMOS25")),
-        Subsignal("alert", Pins("HPC:LA19_N"), IOStandard("LVCMOS25")),
+        Subsignal("enable", Pins("HPC:LA21_P"), IOStandard("LVCMOS33")),
+        Subsignal("alert", Pins("HPC:LA19_N"), IOStandard("LVCMOS33")),
     ),
     ("PoCXP", 2,
-        Subsignal("enable", Pins("HPC:LA22_N"), IOStandard("LVCMOS25")),
-        Subsignal("alert", Pins("HPC:LA19_P"), IOStandard("LVCMOS25")),
+        Subsignal("enable", Pins("HPC:LA22_N"), IOStandard("LVCMOS33")),
+        Subsignal("alert", Pins("HPC:LA19_P"), IOStandard("LVCMOS33")),
     ),
     ("PoCXP", 3,
-        Subsignal("enable", Pins("HPC:LA22_P"), IOStandard("LVCMOS25")),
-        Subsignal("alert", Pins("HPC:LA20_N"), IOStandard("LVCMOS25")),
+        Subsignal("enable", Pins("HPC:LA22_P"), IOStandard("LVCMOS33")),
+        Subsignal("alert", Pins("HPC:LA20_N"), IOStandard("LVCMOS33")),
     ),
 
     ("i2c_fmc", 0,
         Subsignal("scl", Pins("HPC:IIC_SCL")),
         Subsignal("sda", Pins("HPC:IIC_SDA")),
-        IOStandard("LVCMOS25")
+        IOStandard("LVCMOS33")
     ),
 
     ("3V3", 0, Pins("HPC:PG_M2C")),