Field Name             Bits   Default   Description
HIZ_WRINDEX            17:2   0x0       Self-incrementing write index into the HiZ RAM.
                                        Starting write index must start on a DWORD boundary.
                                        Each time ZB_HIZ_DWORD is written, this index will
                                        autoincrement. HIZ_OFFSET and HIZ_PITCH are not
                                        used to compute read/write address to HIZ ram, when it
                                        is accessed through WRINDEX and DWORD
