International Business Machines Corporation

Patrick Massi

Christian A Jacquart

Denis Chevalier

Guy Platel

Pierre Austruy

Michel Geneste

Jean-Paul Conjeaud

Jean Gallian

A hot plug circuit insuring that the plugging of cards to a board is performed in the hot-plug mode when the cards are supplied from a common power supply located on one of the cards or on the board. This circuit (62) limits the surge current generated at the interconnection of first circuits (30) arranged on a first card (1) and powered by a supply device (2) providing a first supply voltage (ground) on a first supply line (36) and a second supply voltage (+V) on a second supply line (34), with second circuit (24) on a second card powered by the supply device (2) through a third supply line (74) and fourth supply line (76). The surge current results from the charge of a decoupling capacitor of capacitance Cd arranged on the second card between the third and fourth supply lines when the cards are interconnected through an interconnecting arrangement (14, 12, 22). The hot plug circuit comprises a controlled ramp generation device connected to the first and second supply lines and activated when the connection between the first and third supply line is completed through the connecting arrangement to start the generation on the fourth supply line of a first ramp voltage Vb derived from the voltages on the first and second supply lines, said ramp voltage having an adjustable slope a=dVb/dt, whereby the surge current i which is equal to a.Cd can be limited to a desired value by adjusting the slope value a.

Hot-plugging circuit for the interconnection of cards to boards

A communication controller CCP includes line adapters (104-i) each having a storage which is loaded with a general application program during an initialization phase. The line adapters allow the attachment and the communication of different telecommunication entities, e.g. a LAN, a teleprocessing line etc. . . The CCP is connected by means of a control adapter to a local control terminal (100) which is associated with a storage for storing the different general application programs which are likely to be required by the different line adapters. A storage contains an access key comprising data relative to the types and the number of line adapters of any type which are authorized to be loaded with the general application program stored in the storage controlled by the control terminal. The CCP also has logic for checking whether a loading request received from one adapter complies with the contents of the stored access key in order to prevent the loading of an unauthorized line adapter. A method is disclosed for performing the loading of a line adapter card which is attached to a communication controller product CCP, the line adapter card being loadable with a general application program during an initialization phase. The method includes the steps of receiving a request from a determined line adapter to be loaded with the corresponding general application program which is loaded in its said storage, and of checking whether the requesting line adapter is included in a list of line adapters which are authorized to be loaded with their corresponding general program application. The method further includes checking whether the number of already defined line adapters which are of the same type as the one which requests the loading operations does not exceed a predetermined value, and of eventually preventing the loading of the requesting line adapter in the case when one of the preceding conditions is not satisfied.

Programmable communication controller line adapter and method for

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St. Laurent du Var, France

Patrick Massi