Calibrating communication lines
AssigneeHewlett-Packard Development Company, L.P.
InventorsXavier Ponce Garcia, Jordi Hernandez Creus, Ricard Silvestre
Life of this patent
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Abstract
Devices and methods for calibrating communication lines are disclosed. A clock sets a frequency of transmission through a communication line. A delay compensator, comprising multi-tap delay lines introduces delays in a transmitted message to compensate for skew in the communication line. An error comparator, coupled to the delay compensator, identifies errors in the messages transmitted through the multi-tap delay lines above an error margin. A delay selector, coupled to the error comparator and to the delay compensator, selects taps of the multi-tap delay lines of the delay compensator. Taps of the multi-tap delay lines where no errors are identified for the selected clock frequency are stored in a memory.
Claims20
A device to calibrate a communication line, comprising:
- a clock to set a frequency of transmission through the communication line;
- a delay compensator, comprising multi-tap delay lines to introduce delays in a transmitted message to compensate for skew in the communication line;
- an error comparator, coupled to the delay compensator, to identify errors in the messages transmitted through the multi-tap delay lines above an error margin;
- a delay selector, coupled to the error comparator and to the delay compensator, to select taps of the multi-tap delay lines of the delay compensator;
- and
- a memory to store taps of the multi-tap delay lines when no errors are identified for the selected clock frequency.
A method of calibrating a communication line comprising:
- setting a frequency of communication;
- sending a predetermined message over the communication line;
- receiving the predetermined message at a delay compensator;
- delaying sampling of the predetermined message using selected tap delays;
- for each selected tap delay, performing comparison of the sampled delayed message with the transmitted predetermined message;
- and
- storing indications of the result of the performed comparisons in a table.
A printer comprising:
- a printer engine board;
- a printer carriage board;
- a cable connecting the printer engine board and the printer carriage board;
- a clock to set a data rate of transmission through the cable;
- wherein,
- the printer carriage board comprises cable calibration logic to compensate skew of the cable, the cable calibration logic comprising:
- a delay compensator to introduce selected delays in a transmitted message;
- an error comparator, coupled to the delay compensator, to identify errors in the messages transmitted through the delay compensator;
- a delay selector, coupled to the error comparator and to the delay compensator, to select delays of the delay compensator;
- and
- a memory to store indications of the errors identified for the selected delays.
A method of categorizing a multi-line cable, comprising:
- selecting a signal transmission frequency;
- transmitting a preselected signal over the multi-line cable;
- introducing multiple delays to the received signal;
- identifying delays, from the multiple introduced delays, resulting in correct reception of the preselected signal;
- and
- categorizing the cable based on the identified delays.
Dependencies are inferred from the claim text.