docs/creating_new_ip: Add lore on 1.00.a

Explain how it came to be and how to handle

Signed-off-by: Jorge Marques <jorge.marques@analog.com>

Author: gastmaier

docs/user_guide/ip_cores/creating_new_ip.rst

@@ -303,6 +303,10 @@ Software drivers parse the ``VERSION`` register for feature handling across
 versions. The patch number shouldn't have to be handled by software drivers, if
 it seems necessary to, consider incrementing the minor number instead.
 
+Due to AMD Xilinx old default IP core version, many IP cores bindings start at
+1.00.a. For compatibility, the patch value is kept, but should be treated as
+decimal instead of character.
+
 Xilinx
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