A memory device includes memory cell array including a first and second plane and first and second caches. A controller is configured to output status information in response to a status read command. The status information indicating the states of the caches. The controller begins a first process in response to a command addressed to the first plane if the status information indicates the first and second caches are in the ready state, and begins a second process on the second plane according to a second command to the second plane if the status information indicates at least the second cache is in the ready state.