Index: /firmware/FTU/FTU_top_tb.vhd
===================================================================
--- /firmware/FTU/FTU_top_tb.vhd	(revision 12031)
+++ /firmware/FTU/FTU_top_tb.vhd	(revision 12032)
@@ -288,8 +288,67 @@
     -- wait until FTU is initialized
     ---------------------------------------------------------------------------
-    wait for 150us;
-    ---------------------------------------------------------------------------
-    -- test one RS485 command (28 byte)
-    ---------------------------------------------------------------------------
+    --wait for 150us;
+    ---------------------------------------------------------------------------
+    -- test broken RS485 command
+    ---------------------------------------------------------------------------
+--    assign_rs485("01000000"); --start delimiter
+--    wait for 0us;
+--    assign_rs485("00000000"); --FTU address
+--    wait for 0ns;
+--    assign_rs485("11000000"); --FTM address
+--    wait for 0ns;
+--    assign_rs485("00000001"); --FTM firmware ID
+--    wait for 0ns;
+--    assign_rs485("00000110"); --instruction
+--    wait for 0us;
+--    assign_rs485("00010100"); --data byte 01
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 02
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 03
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 04
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 05
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 06
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 07
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 08
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 09
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 10
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 11
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 12
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 13
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 14
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 15
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 16
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 17
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 18
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 19
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 20
+--    wait for 0ns;
+--    assign_rs485("00000000"); --data byte 21
+--    wait for 0ns;
+--    assign_rs485("00000000"); --CRC error counter (not used)
+--    wait for 0ns;
+    assign_rs485("01001101"); --check sum
+    ---------------------------------------------------------------------------
+    -- send regular RS485 command
+    ---------------------------------------------------------------------------
+    wait for 8us;
     assign_rs485("01000000"); --start delimiter
     wait for 0us;
@@ -300,7 +359,7 @@
     assign_rs485("00000001"); --FTM firmware ID
     wait for 0ns;
-    assign_rs485("00000110"); --instruction
+    assign_rs485("00000000"); --instruction
     wait for 0us;
-    assign_rs485("00010100"); --data byte 01
+    assign_rs485("00000001"); --data byte 01
     wait for 0ns;
     assign_rs485("00000000"); --data byte 02
@@ -346,9 +405,9 @@
     assign_rs485("00000000"); --CRC error counter (not used)
     wait for 0ns;
-    assign_rs485("01001101"); --check sum
-    ---------------------------------------------------------------------------
-    -- wait enough time and send another command
-    ---------------------------------------------------------------------------
-    wait for 1500us;
+    assign_rs485("01010010"); --check sum
+    ---------------------------------------------------------------------------
+    -- repeat regular RS485 command after FTM time-out
+    ---------------------------------------------------------------------------
+    wait for 2000us;
     assign_rs485("01000000"); --start delimiter
     wait for 0us;