Prompt resynchronization for a serial interface
AssigneeCirrus Logic, Inc.
InventorDouglas F. Pastorello
Life of this patent
Estimating the term…
Abstract
Byte synchronization between a bus master and a serial interface or other bus slave is maintained and promptly corrected by using a unique signal, issued by the serial interface, to promptly and unambiguously notify the bus master of a loss of synchronization, followed by prompt resynchronization by the bus master. The serial interface sets a selected indicium in a status register equal to a selected value, when an invalid command is sensed at the interface. The bus master reads the status register and, when the selected indicium has the selected value, promptly resynchronizes the serial interface without further delay.
Claims8
A method for byte synchronization at a serial interface in an integrated circuit, the method comprising:
- receiving a command at a serial interface in an integrated circuit;
- determining if the received command is a valid command;
- when the received command is a valid command, processing the command;
- when the command is not a valid command, setting a selected indicium in a status register, which is readable by a bus master, equal to a selected indicium value;
- causing the bus master to read the selected indicium in the status register;
- and
- when the selected indicium read by the bus master has the selected indicium value, performing a byte resynchronization sequence at the serial interface.
Apparatus for byte synchronization at a serial interface in an integrated circuit, the apparatus comprising:
- a bus master and an associated status register that is readable by the bus master;
- a serial interface in an integrated circuit that receives a command and determines if the received command is a valid command;
- and
- when the received command is a valid command, the interface processes the command;
- when the command is not a valid command, the interface causes a selected indicium in the status register to be set equal to a selected indicium value;
- wherein the bus master reads the selected indicium in the status register and, when the selected indicium read by the bus master has the selected indicium value, the bus master performs a byte resynchronization sequence at the serial interface.
A method for providing reliable indication of presence of an error condition at a serial interface in an integrated circuit, the method comprising:
- providing a reference set of valid commands at the serial interface;
- receiving a command at the serial interface, and comparing the received command with the reference set of commands;
- when the received command is not one of the reference set of commands, providing a selected value for a selected status register associated with the serial interface an interpreting presence of the selected value in the status register as indicating presence of a communications error.
Dependencies are inferred from the claim text.