| 摘要 |
<p>The present invention is circuitry which is employed with a data terminal, which data terminal in turn is part of a system including a main computer. The present circuitry includes a microprocessor which is connected to the main computer and to the keyboard. The microprocessor processes signals from both the main computer and the keyboard. The system has a plurality of operational function circuits, such as a circuit to effect smooth scrolling on a data display. Logic circuitry is connected between the microprocessor and the operational function circuits. The logic circuitry provides a first path which permits signals, generated in response to instructions from the main computer, to pass therethrough to select one of the operational function circuits and simultaneously therewith to turn the selected circuit either "on" or "off". The logic circuitry also provides a second path which permits signals, generated in response to instructions from the keyboard, to pass therethrough to select one of the operational function circuits and turn that circuit either "on" or "off". A circuit to generate an impeding signal is also included and is activated by signals from the microprocessor in response to signals from the keyboard. This last-mentioned generator circuit is connected to impede signals which would otherwise be transmitted along the first path, whereby the keyboard, after selecting a particular operational function circuit, can "lock in" that circuit so that the main computer cannot turn that selected circuit "off".</p> |
