Interface shutdown mode for a data bus slave
AssigneeLSI Logic Corporation
InventorsRussell B. Stuber, Randall S. Miller
Life of this patent
Estimating the term…
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.
Claims20
A slave device for transferring data via a data bus with respective ones of a plurality of master devices wherein an arbiter grants each of the master devices access to the data bus, and wherein data are transferred based on commands from a master device, the slave device comprising:
- a status register responsive to a command queue that receives commands from a master device to provide a first signal when the command queue is full of commands;
- a configuration register responsive to a predetermined condition of the slave device to provide a second signal;
- and
- a bus control responsive to either the first or second signal and to the command to operate the data bus in a predetermined mode.
A process of operating a slave device in a shutdown or initializing condition of the slave device or a device operated by the slave device, where the slave device is coupled to a data bus and responsive to commands from master devices to transfer data between the respective master device and the slave device, wherein the slave device includes a status register responsive to a full condition of a command queue that receives commands for execution to issue a full signal, and a bus control responsive to the full signal and to a command to operate the data bus to a predetermined mode, the process comprising steps of:
- a) providing a control signal in response to a shut down or initialization condition;
- and
- b) operating the bus control in response to the control signal and the command to operate the data bus to the predetermined mode.
In a data bus for transferring data between a slave device and respective ones of a plurality of master devices, wherein the slave device includes transfer apparatus for transferring data to and from the respective master device, a status register that provides a first signal when a command queue that stores commands from master devices for execution is full, and a bus control responsive to the first signal and the command for operating the data bus to a predetermined mode, the improvement comprising:
- a configuration register in the slave device responsive to a shutdown or initialization condition of the slave device or a device operated by the slave device to provide a second signal;
- and
- the bus control is responsive to the second signal and to the command to operate the data bus in the predetermined mode.
Dependencies are inferred from the claim text.