A method and apparatus to avoid collisions between row activate and column
read or column write commands is presented. A memory controller includes
control logic, activate allowed logic, and last column counter logic. The
control logic sends particular values to the activate allowed logic and
the last column counter logic at the beginning of a read or write
operation, such as a new command load value, a read count value, and a
write count value. In turn, the control logic receives an activate
allowed signal from the activate allowed logic, which indicates the times
at which a new activate command may be issued. As a result, the memory
controller allows an activate command to commence on "even" command
cycles or anytime after the last outstanding column command has been
issued.