diff --git a/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlResourceDataCodeGen.c b/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlResourceDataCodeGen.c
index 332962bed4..4ca63ccd23 100644
--- a/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlResourceDataCodeGen.c
+++ b/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlResourceDataCodeGen.c
@@ -1257,7 +1257,12 @@ AmlCodeGenRdRegister (
   AML_DATA_NODE                         *RdNode;
   EFI_ACPI_GENERIC_REGISTER_DESCRIPTOR  RdRegister;
 
-  if ((AccessSize > EFI_ACPI_6_4_QWORD)  ||
+  // Cf. ACPI 6.4, s14.7 Referencing the PCC address space
+  // The AccessSize represents the Subspace Id for the PCC address space.
+  if (((AddressSpace == EFI_ACPI_6_4_PLATFORM_COMMUNICATION_CHANNEL) &&
+       (AccessSize > 256)) ||
+      ((AddressSpace != EFI_ACPI_6_4_PLATFORM_COMMUNICATION_CHANNEL) &&
+       (AccessSize > EFI_ACPI_6_4_QWORD)) ||
       ((NameOpNode == NULL) && (NewRdNode == NULL)))
   {
     ASSERT (0);