Electrical computers and digital data processing systems: input/ – Intrasystem connection
Reexamination Certificate
2000-09-26
2004-06-29
Ray, Gopal C. (Department: 2181)
Electrical computers and digital data processing systems: input/
Intrasystem connection
C710S062000, C710S063000, C370S464000, C455S186100, C712S208000
Reexamination Certificate
active
06757760
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of managing the reception of data received by a device. More particularly, the present invention relates to the field of managing the reception of data received on a channel by a device.
BACKGROUND OF THE INVENTION
The IEEE standard, “IEEE 1394 Standard For A High Performance Serial Bus,” Draft ratified in 1995, is an international standard for implementing an inexpensive high-speed serial bus architecture which supports both asynchronous and isochronous format data transfers. Isochronous data transfers are real-time transfers which take place such that the time intervals between significant instances have the same duration at both the transmitting and receiving applications. Each packet of data transferred isochronously is transferred in its own time period. The IEEE 1394-1995 standard bus architecture provides up to sixty-four (64) channels for isochronous data transfer between applications. A six bit channel number is broadcast with the data to ensure reception by the appropriate application. This allows multiple applications to simultaneously transmit isochronous data across the bus structure. Asynchronous transfers are traditional data transfer operations which take place as soon as possible and transfer an amount of data from a source to a destination.
The IEEE 1394-1995 standard provides a high-speed serial bus for interconnecting digital devices thereby providing a universal I/O connection. The IEEE 1394-1995 standard defines a digital interface for the applications thereby eliminating the need for an application to convert digital data to analog data before it is transmitted across the bus. Correspondingly, a receiving application will receive digital data from the bus, not analog data, and will therefore not be required to convert analog data to digital data. The cable required by the IEEE 1394-1995 standard is very thin in size compared to other bulkier cables used to connect such devices. Devices can be added and removed from an IEEE 1394-1995 bus while the bus is active. If a device is so added or removed the bus will then automatically reconfigure itself for transmitting data between the then existing nodes. A node is considered a logical entity with a unique identification number on the bus structure. Each node provides an identification ROM, a standardized set of control registers and its own address space.
The IEEE 1394-1995 standard defines a protocol as illustrated in FIG.
1
. This protocol includes a serial bus management block
10
coupled to a transaction layer
12
, a link layer
14
and a physical layer
16
. The physical layer
16
provides the electrical and mechanical connection between a device or application and the IEEE 1394-1995 cable. The physical layer
16
also provides arbitration to ensure that all devices coupled to the IEEE 1394-1995 bus have access to the bus as well as actual data transmission and reception. The link layer
14
provides data packet delivery service for both asynchronous and isochronous data packet transport. This supports both asynchronous data transport, using an acknowledgement protocol, and isochronous data transport, providing real-time guaranteed bandwidth protocol for just-in-time data delivery. The transaction layer
12
supports the commands necessary to complete asynchronous data transfers, including read, write and lock. The serial bus management block
10
contains an isochronous resource manager for managing isochronous data transfers. The serial bus management block
10
also provides overall configuration control of the serial bus in the form of optimizing arbitration timing, guarantee of adequate electrical power for all devices on the bus, assignment of the cycle master, assignment of isochronous channel and bandwidth resources and basic notification of errors.
As discussed above, an IEEE 1394-1995 device includes the capability to transmit and receive isochronous data over multiple channels. The IEEE 1394-1995 standard provides for up to sixty-four different isochronous channels to be used within an IEEE 1394-1995 network of devices. However, in current implementations, certain IEEE 1394-1995 devices are being built with the capability to only transmit and receive isochronous data over a subset of less than sixty-four channels. When receiving data on an isochronous channel, that data must be processed by the receiving device. This processing includes any or all of displaying, manipulating, forwarding and storing. Often, data received on different isochronous channels is processed differently, depending on the type of device from which the data is received, the type of data that is received and the desired use of the data. If data received on an isochronous channel is not received and processed efficiently, errors in the display or use of the data can result.
SUMMARY OF THE INVENTION
An apparatus for dispatching a processing element to a program location based on a channel number of received data includes a channel pointer register having a number of storage locations each with a channel number field, a valid bit field and a corresponding instruction pointer field. When an isochronous channel is allocated for use for reception, the host device programs the channel number and a corresponding instruction pointer value into a storage location. When a storage location is programmed, a valid bit within that storage location is also preferably set. The corresponding instruction pointer value points to a series of instructions which are to be used to process data received on that isochronous channel. When isochronous data is then received, the channel number on which the data is received is compared to the channel numbers within the valid storage locations in the channel pointer register. If one of the channel numbers within a valid storage location matches the channel number of the received data, then the corresponding instruction pointer value is output and the data is processed according to a series of instructions beginning at the location specified by the corresponding instruction pointer value. Otherwise, if the channel number of the received data does not match any of the channel numbers within valid storage locations then a default instruction pointer value is output and the received data is processed according to a series of instructions beginning at the location specified by the default instruction pointer value. The series of instructions beginning at the location specified by the default instruction pointer value are used to broadcast data received on a single channel on all appropriate channels, multicast data received on a single channel to a select group of channels, handle errors and exceptions related to received data and unprogrammed channel numbers, ignore data received on a channel, route data received on a first channel to one or more different channels, to monitor the active channels on the bus and any other appropriate action to process data received on a channel with no corresponding valid instruction pointer value.
In one aspect of the invention, a method of processing received data having a real-time component comprises receiving data having the real-time component on a received channel number, comparing the received channel number to stored channel numbers within a plurality of memory locations, each of the plurality of memory locations including a corresponding address value specifying a starting address for a series of instructions for processing data received on a corresponding stored channel number, providing the corresponding address value corresponding to the stored channel number matching the received channel number as an output address value if one of the stored channel numbers matches the received channel number and providing a default address value as the output address value if none of the stored channel numbers matches the received channel number. The method further includes allocating an allocated channel number for receiving data and programming the allocated channel number and a corresponding allocated a
Fairman Bruce A.
Liu Jung-Jen
Haverstock & Owens LLP
Ray Gopal C.
Sony Corporation
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