Methods and apparatus for synchronizing data transferred across a multi-pin asynchronous serial interface
First Claim
1. A method comprising:
- receiving data on a plurality of serial data channels and a framing signal on a framing channel that is physically distinct from the plurality of serial data channels, wherein the framing signal and the data are each generated by a transmitter, and wherein the framing signal is an asynchronous signal that indicates a frame boundary;
initially determining a plurality of offset values in a correlation mode, each offset value indicating the amount of skew observed between the framing channel and one of the plurality of serial data channels;
after exiting the correlation mode, storing the data received on each of the plurality of serial data channels in at least one buffer;
monitoring the framing signal received from the transmitter on the framing channel to identify the frame boundary; and
extracting parallel data from the at least one buffer, wherein the location of the parallel data within the at least one buffer is identified by the frame boundary in combination with at least one of the plurality of offset values initially determined in the correlation mode.
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Accused Products
Abstract
Methods, devices and systems are provided for word synchronizing multiple serial data bitstreams (106) with a serial framing signal (106A). Offset values (420) are determined (512) from the relative locations of predetermined data correlation values (107) stored within the data buffers during a correlation mode to indicate the amount of skew observed between the framing channel and each of serial data channels. Data received during subsequent operation of each data stream is stored a buffer (402), and the framing signal (106A) is monitored to identify a boundary between data words. When a frame boundary occurs, parallel data is extracted from the buffer using the previously-stored offset values to compensate for bit skew between the data and framing channels.
46 Citations
19 Claims
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1. A method comprising:
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receiving data on a plurality of serial data channels and a framing signal on a framing channel that is physically distinct from the plurality of serial data channels, wherein the framing signal and the data are each generated by a transmitter, and wherein the framing signal is an asynchronous signal that indicates a frame boundary; initially determining a plurality of offset values in a correlation mode, each offset value indicating the amount of skew observed between the framing channel and one of the plurality of serial data channels; after exiting the correlation mode, storing the data received on each of the plurality of serial data channels in at least one buffer; monitoring the framing signal received from the transmitter on the framing channel to identify the frame boundary; and extracting parallel data from the at least one buffer, wherein the location of the parallel data within the at least one buffer is identified by the frame boundary in combination with at least one of the plurality of offset values initially determined in the correlation mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A device comprising:
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a multi-pin asynchronous interface configured to receive a plurality of asynchronous serial bitstreams generated by a data transmitter and transmitted on a plurality of physically separate channels, the plurality of serial bitstreams comprising a framing bitstream and a plurality of data bitstreams, wherein the framing bitstream is an asynchronous bitstream that is provided on a framing channel that is physically distinct from channels that provide the data bitstreams, and wherein the framing bitstream comprises framing data indicating a frame boundary; a plurality of buffers, each buffer corresponding to one of the serial bitstreams; a plurality of word search modules each corresponding to one of the plurality of buffers, wherein each of the plurality of word search modules is configured to generate an offset signal identifying a location of a predetermined bit pattern in the corresponding buffer in an initial correlation mode; and a plurality of parallel word extraction modules, each of the plurality of parallel word extraction modules coupled to an associated one of the buffers and to an associated one of the word search modules each corresponding to one of the data bitstreams, and wherein each parallel word extraction module is configured to extract a parallel data word from the associated buffer in an operating mode after the correlation mode is complete using the data offset signal produced by the associated word search module and the framing data provided by data transmitter via the framing bitstream. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A system for synchronizing a plurality of serial bitstreams, the system comprising:
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a multi-pin asynchronous interface configured to receive the plurality of serial bitstreams from a transmitter, the plurality of serial bitstreams comprising a framing bitstream and a plurality of data bitstreams each having a common bitrate, wherein the framing bitstream is an asynchronous signal that is provided on a physically separate pin from the data bitstreams and that indicates a frame boundary; a clock generator configured to produce a common clock signal having a frequency substantially equal to an integer multiple of the common bitrate; a plurality of bit synchronization modules each associated with one of the plurality of serial bitstreams and configured to receive the common clock signal, and to bit synchronize the associated bitstream to the other serial bitstreams using the common clock signal; and a word synchronization module configured to receive each of the bit synchronized bitstreams from the plurality of bit synchronization modules and to extract parallel data words therefrom, the word synchronization module comprising; a plurality of buffers, each buffer corresponding to one of the synchronized bitstreams; a plurality of word search modules each corresponding to one of the plurality of buffers, wherein each of the plurality of word search modules is configured to generate an offset signal identifying a location of a predetermined bit pattern in the corresponding buffer in an initial correlation mode; and a plurality of parallel word extraction modules, each of the plurality of parallel word extraction modules coupled to an associated one of the buffers and to an associated one of the word search modules each corresponding to one of the data bitstreams, and wherein each parallel word extraction module is configured to extract a parallel data word from the associated buffer in an operating mode after the correlation mode is complete using the data offset signal produced by the associated word search module and the frame boundary indicated by the framing bitstream. - View Dependent Claims (18, 19)
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Specification