Abstract: A slave device receives commands from a master device for execution on a first-in, first-out basis. A status register is responsive to a queue of commands to provide a COMMAND_STATUS_FULL signal when the queue is full of commands. A configuration register provides a SHUT_DOWN signal identifying a shutdown status of the slave device. A bus control is responsive to the command and to either the COMMAND_STATUS_FULL or SHUT_DOWN signal to idle the data bus and deny the requesting master device access to the data bus if the command is for a non-locked transfer, or to stall the data bus if the command is for a locked transfer request.