Address Update
The addren signal is an additional clock enable signal for the address
register which allows you to enable or disable (stall) the address update. When disabled
while performing read/write operation, it holds the previous address value. The default
value for the address enable is high (enabled).
In the following example, the data BB on rdata
overwrites the previously written AA in address
addr[02] since the addren signal is low when the
we signal is high. The data BB will not be written
to address addr[03] so rdata outputs the previously
stored data.