diff --git a/test/simulator/user_interface.cpp b/test/simulator/user_interface.cpp
new file mode 100644
index 0000000..7ed998a
--- /dev/null
+++ b/test/simulator/user_interface.cpp
@@ -0,0 +1,79 @@
+/**
+ * @file These are the simulated implementations of the user interfaces declared
+ *       in hei_user_interface.hpp
+ */
+
+#include "simulator.hpp"
+
+#include <endian.h>
+
+#include <hei_user_interface.hpp>
+
+namespace libhei
+{
+
+//------------------------------------------------------------------------------
+
+ReturnCode registerRead(const Chip& i_chip, void* o_buffer, size_t& io_bufSize,
+                        uint64_t i_regType, uint64_t i_address)
+{
+    ReturnCode rc{};
+
+    HEI_ASSERT(nullptr != o_buffer);
+    HEI_ASSERT(0 != io_bufSize);
+
+    switch (i_regType)
+    {
+        // BEGIN temporary code
+        // TODO: add cases for REG_TYPE_SCOM and REG_TYPE_ID_SCOM
+        case REG_TYPE_SCOM:
+        {
+            uint64_t x = htobe64(0x8800000000000000);
+            memcpy(o_buffer, &x, sizeof(x));
+            break;
+        }
+        case REG_TYPE_ID_SCOM:
+        {
+            uint64_t x = htobe64(0x8000);
+            memcpy(o_buffer, &x, sizeof(x));
+            break;
+        }
+        // END temporary code
+        default:
+            rc = RC_REG_ACCESS_FAILURE;
+            HEI_ERR("registerRead(%p,%p,%lx,%lx,%lx)", i_chip.getChip(),
+                    o_buffer, io_bufSize, i_regType, i_address);
+    }
+
+    return rc;
+}
+
+//------------------------------------------------------------------------------
+
+#ifndef __HEI_READ_ONLY
+
+ReturnCode registerWrite(const Chip& i_chip, void* i_buffer, size_t& io_bufSize,
+                         uint64_t i_regType, uint64_t i_address)
+{
+    ReturnCode rc{};
+
+    HEI_ASSERT(nullptr != i_buffer);
+    HEI_ASSERT(0 != io_bufSize);
+
+    switch (i_regType)
+    {
+        // TODO: add cases for REG_TYPE_SCOM and REG_TYPE_ID_SCOM
+        default:
+            rc = RC_REG_ACCESS_FAILURE;
+            HEI_ERR("registerWrite(%p,%p,%lx,%lx,%lx)", i_chip.getChip(),
+                    i_buffer, io_bufSize, i_regType, i_address);
+    }
+
+    return rc;
+}
+
+#endif
+
+//------------------------------------------------------------------------------
+
+} // namespace libhei