JPH054032Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a keyboard widely used as an input device in an information processing device, and particularly relates to a reset function of a keyboard equipped with a one-chip microcomputer (microcomputer).

[Conventional technology]

Conventionally, this type of keyboard has had its one-chip microcomputer placed in a hardware reset state by receiving a reset signal from a connected host device or by power-on reset.

[Problem that the invention attempts to solve]

As mentioned above, conventional keyboards are configured so that the one-chip microcomputer inside the keyboard goes into a hardware reset state when it receives a reset signal from the host device. The problem is that even if the microcontroller starts operating abnormally, the one-chip microcontroller itself cannot return to normal operation.

[Means for solving problems]

The present invention, in a keyboard having a one-chip microcomputer for control, detects the state of each key switch in a key matrix at regular intervals, and when all the key switches are off, initializes the one-chip microcomputer. It is characterized by having means.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention. One embodiment of the present invention includes a key matrix 1 in which a matrix of key switches 11 is arranged, a one-chip microcomputer 2 for control, an interface circuit 3, and a connector 4 for connection to a host device.

An overview of the operation will be explained with reference to FIG. 2 as well. The one-chip microcomputer 2 individually checks whether each of the key switches 11 arranged in the key matrix 1 is on or off, and converts the state of each key switch that is turned on or off into an individual assignment code. This code is transferred to a host device (not shown) via the interface circuit 3 and connector 4 (loop routine 10). The one-chip microcomputer 1 generates a timer interrupt 30 at regular intervals while executing a loop routine 10 for detecting the states of the keys in the key matrix.
is activated to interrupt the loop routine 10 and execute a timer interrupt reset processing routine 20, and after execution of this routine 20, the loop routine 10 returns to the interrupting point.

Figure 3 shows the timer interrupt reset processing routine 20.
This is an overview flowchart. If all the keyswitches 11 of the keyboard are not in the off state, the process returns to the loop routine 10 in which the state of the keyswitches 11 of the keyboard is detected. Also, if all the key switches 11 of the keyboard are off,
Ports, buses in one chip microcontroller 1,
The RAM, registers, and flags are initialized, the program stack pointer is manipulated, and a return start address upon return to the loop routine 10 is arbitrarily set, and the loop routine 10 is returned.

[Effect of idea]

As explained above, the present invention provides a timer interrupt reset processing routine that is executed periodically in the processing program of the one-chip microcomputer in the keyboard, so that the one-chip microcomputer malfunctions in response to static electricity or noise. Even if a normal operation is started, normal operation can be resumed when the timer interrupt reset processing routine is executed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention;
This figure is a diagram illustrating an overview of the operation in FIG. 1, and FIG. 3 is a general flowchart of the timer interrupt reset processing routine in FIG. 2. 1...Key matrix, 2...One-chip microcomputer, 3...Interface circuit, 4...Connector.

Claims (1)

[Scope of utility model registration request] A keyboard having a one-chip microcomputer for control, comprising means for detecting the state of each key switch of a key matrix at regular intervals and initializing the one-chip microcomputer when all the key switches are in an off state. A keyboard characterized by: