DEBUG mode for a data bus
AssigneeLSI Logic Corporation
InventorsRussell B. Stuber, Robert W. Moss, David O. Sluiter
Life of this patent
Estimating the term…
Abstract
A slave device includes a queue that receives commands or data from a master device for execution on a first-in, first-out basis. A status register is responsive to the queue to provide a STATUS_FULL signal when the queue is full of commands and a STATUS_EMPTY signal when the queue is empty. A configuration register provides a DEBUG signal identifying a maintenance status of the slave device. A bus control provides a QUEUE_FULL signal in response to either (1) the STATUS_FULL signal or (2) the DEBUG signal and not the STATUS_EMPTY signal to split further commands or stall the data bus.
Claims20
A slave device for transferring data via a data bus with respective ones of a plurality of master devices wherein data are transferred based on a command from a master device, the slave device receiving commands in a queue for execution on a first-in, first-out basis by a device fed by the slave device, the queue providing a first status signal representing a full condition of the queue, the slave device comprising:
- a status register responsive to the queue to provide a second status signal when the command queue is not empty;
- and
- a bus control responsive to the first status signal to operate the bus in a predetermined mode and responsive to the second status signal and a control signal to operate the bus in the predetermined mode.
A process of operating a slave device in a maintenance mode, where the slave device is coupled to a data bus and responsive to commands from master devices to transfer data between a respective master device and the slave device, wherein data or commands are received in a queue for execution on a first-in, first-out basis by a device fed by the slave device, and the slave device includes
- a status register responsive to the queue to provide a first status signal when the queue is full and a second status signal when the queue is not empty, and
- a bus control responsive to a queue full signal to operate the bus to a predetermined mode, the slave device providing the queue full signal in response to the first status signal, the process comprising steps of:
- a) receiving a control signal at the slave device;
- and
- b) providing the queue full signal in response to both the second status signal and the control signal.
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 a data queue for transferring data between the slave device and the respective master device on a first-in first-out basis, a command queue that stores commands from master devices for execution by a device fed by the slave device on a first-in, first-out basis, a status register that indicates whether at least one of the queues is full and whether the at least one queue is empty, a process comprising steps of:
- a) receiving a debug signal at the slave device;
- and
- b) indicating that the at least one queue is full in response to the debug signal when the at least one queue is not empty.
Dependencies are inferred from the claim text.