Advanced data link controller
First Claim
1. In a data link controller for controlling data communications between a bidirectional data bus and a communications link transmitting and receiving data in serial form, said data link controller comprising a transmitter, a receiver, and a status register, the improvement wherein said status register comprises a plurality of individual bit locations each of which may be concurrently set to a predetermined logic state by control logic in response to one of a first set of operating conditions within said data link controller and which locations may be subsequently read by a data processing system located externally to said data link controller and coupled to said bidirectional data bus, said individual bit locations being arranged in a first prioritized pattern, said data processing system controlling the operation of said data link controller in response to the contents of said status register bit locations in accordance with said first prioritized pattern.
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Abstract
A bit-oriented data link controller provides the interface between a microcomputer or terminal and a data communications link. The data link controller is capable of accommodating the three most commonly available bit-oriented data link control protocols, namely Synchronous Data Link Control SDLC, High Level Data Link Control HDLC, and Advanced Data Communications Control Procedure ADCCP. The data link controller provides the data communications interface for both primary and secondary stations in stand-alone, polling, and loop configurations.
86 Citations
7 Claims
- 1. In a data link controller for controlling data communications between a bidirectional data bus and a communications link transmitting and receiving data in serial form, said data link controller comprising a transmitter, a receiver, and a status register, the improvement wherein said status register comprises a plurality of individual bit locations each of which may be concurrently set to a predetermined logic state by control logic in response to one of a first set of operating conditions within said data link controller and which locations may be subsequently read by a data processing system located externally to said data link controller and coupled to said bidirectional data bus, said individual bit locations being arranged in a first prioritized pattern, said data processing system controlling the operation of said data link controller in response to the contents of said status register bit locations in accordance with said first prioritized pattern.
Specification