update user defines

verilog/rtl/user_defines.v

diff --git a/verilog/rtl/user_defines.v b/verilog/rtl/user_defines.v
index e577931..81c0430 100644
--- a/verilog/rtl/user_defines.v
+++ b/verilog/rtl/user_defines.v
@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2020 Efabless Corporation
+// SPDX-FileCopyrightText: 2022 Efabless Corporation
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -19,17 +19,22 @@
 // User GPIO initial configuration parameters
 `define __USER_DEFINES_H
 
+// deliberately erroneous placeholder value; user required to config GPIO's to other
+`define GPIO_MODE_INVALID                  13'hXXXX
+
+// Authoritive source of these MODE defs is: caravel/verilog/rtl/user_defines.v
 // Useful GPIO mode values.  These match the names used in defs.h.
+//
 `define GPIO_MODE_MGMT_STD_INPUT_NOPULL    13'h0403
-`define GPIO_MODE_MGMT_STD_INPUT_PULLDOWN  13'h0803
-`define GPIO_MODE_MGMT_STD_INPUT_PULLUP    13'h0c03
+`define GPIO_MODE_MGMT_STD_INPUT_PULLDOWN  13'h0c01
+`define GPIO_MODE_MGMT_STD_INPUT_PULLUP    13'h0801
 `define GPIO_MODE_MGMT_STD_OUTPUT          13'h1809
 `define GPIO_MODE_MGMT_STD_BIDIRECTIONAL   13'h1801
 `define GPIO_MODE_MGMT_STD_ANALOG          13'h000b
 
 `define GPIO_MODE_USER_STD_INPUT_NOPULL    13'h0402
-`define GPIO_MODE_USER_STD_INPUT_PULLDOWN  13'h0802
-`define GPIO_MODE_USER_STD_INPUT_PULLUP    13'h0c02
+`define GPIO_MODE_USER_STD_INPUT_PULLDOWN  13'h0c00
+`define GPIO_MODE_USER_STD_INPUT_PULLUP    13'h0800
 `define GPIO_MODE_USER_STD_OUTPUT          13'h1808
 `define GPIO_MODE_USER_STD_BIDIRECTIONAL   13'h1800
 `define GPIO_MODE_USER_STD_OUT_MONITORED   13'h1802