JPS6062259A - Data transmission equipment - Google Patents

Abstract

PURPOSE:To simplify a data transmission equipment and to improve its operability by allowing a parallel system separation type keyboard peripheral circuit to control plural LEDs through one connection line when the output of a D latch coincides with the output of a counter. CONSTITUTION:A coincidence signal generating circuit 20 consists of exclusive OR circuits 13-15, intervals 16-18, and a 3-input AND circuit 19. Only when outputs 1Q, 2Q, and 3Q of the D latch coincide with outputs QB, QC, and QD of the counter 2, the output of the 3-input AND circuit 19 goes up to a high level. Its coincidence signal is transmitted to a keyboard side through only one connection line to latch the outputs of the counter 3 in the D latch 21, and consequently the outputs 1Q, 2Q, and 3Q of the D latch 9 are placed in the same state, thereby driving LEDs 10-12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a keyboard peripheral circuit for a personal computer (hereinafter abbreviated as a personal computer).

[Background of the invention]

Figure 1 is a block diagram of one embodiment of the keyboard peripheral circuit of a conventional keyboard-separated personal computer. show.

In Figure 1, reference numeral 1 is a connection line connecting the keyboard and the computer body, and reducing the number of connection lines is the key to cost reduction in the parallel transmission system. 2 and 6 are binary counters, which are counted up by the same clock signal CK1. Reference numeral 4 denotes a data decoder, and output pulses scan output terminals Q0 to <'ts in response to input 4-pit signals and repeat the same. 5 is a keyboard matrix, which is composed of key switches located at each father point of the X@ and Y axes. Reference numeral 6 denotes a data selector which selects one signal from the input terminals Do to D7 according to an input 6-bit signal and outputs it from the Y terminal.

(If you press one key inch on the key matrix 5, a match signal at a specific timing of the output terminals QB-QH of the counter 3 corresponding to the position of the key switch is output from the Y terminal of the data selector 6. According to this match signal,
D latch 7 is turned on, a signal is output from output terminal Q, and this signal is IRQ I! which determines that a key on the keyboard has been pressed. I! The most significant bit signal of the data is input to the central processing unit (hereinafter abbreviated as MPU) at the same time as the D-inclusive signal. MPU is IRQ
When the signal is input, the KBR signal and the KBW signal are outputted at different timings, the three-state buffer 8 is made conductive by the KBR signal, and the output data of the counter 2 is outputted. At this time, since counters 2 and 3 are counted in synchronization with each other, the output data of counter 2 is the same as the output data of counter 3, that is, the schema)
Data corresponding to the position of the key switch of the IJ clay is input to the MPU. Furthermore, this data is code-converted by the MPU, and it is determined which character, number, or symbol key was pressed, and the data is input as data. On the other hand, K
The input signal of the D latch 9 is latched by the BW signal.

Here, the D latch 9 is for driving the LED, and the 1Q output is C
The 2Q output is for "Katakana" mode display, and the -13Q output is for 6-Hiragana mode display. If all of the IQ, 2Q, and 30 outputs are at zero level, the LED will not light up, but if you press the "CAPS-LOCK" key on the key matrix, the D
The 1Q output of latch 9 becomes low level, and CAPS-L
"OCK" display LED 10 lights up. 1D to 3D inputs of the D latch 9 are controlled by software.

Since there are three LEDs in such a configuration, three connection lines for the LEDs are required independently within the connection line 1.
The increase in the number of connected wires increases the cost of wires and connectors, which is a drawback that is undesirable compared to the parallel type system, which has the advantage of low circuit construction costs.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a computer with excellent cost performance by reducing the number of connecting lines between the keyboard and the computer main body in a parallel type separate keyboard peripheral circuit.

[Summary of the invention]

Taking advantage of the fact that the counter is synchronized with both the computer side and the keyboard side, select the data that matches the LED lighting data from the counter timing 12 to create a matching signal, and then convert this signal into one line. It is transmitted to the keyboard side through a connection line, and the match signal launches the output of the counter on the keyboard side to control multiple LED'f.

[Embodiments of the invention]

FIG. 2 shows an embodiment of the present invention.

13, 14.15 is Exclusif OR (hereinafter Ex0
abbreviated as R) circuit, 16.17.18 is an inverter, 19
Kero human power and circuit. The circuit configured as described above will be referred to as a coincidence signal generation circuit 20.

In EXOR13, the 1Q output of D latch 9 and counter 2
The output becomes low level only when the QD outputs of
The signal is input to the human input circuit 19. The same applies to EXOR14 and EXOR15. That is, the output of D latch 9 is 'Q*2Q,' and the output of counter 2 is QB.
Three-person AND circuit 1 only when QC and QD match each other
The output of No. 9 becomes high level. This coincidence signal is transmitted to the keyboard side through one connection line, and when the output of the counter 3 is latched by the D latch 21 with this signal, the D latch 2
1's output 'Q+ 2Q+3Q is the output IQ of D latch 9
, 2Q, becomes the same state as 30, and it becomes possible to drive LEDlo, 11.12 in the same way as the conventional example shown in Figure 1. By adding more parts in the signal generation circuit 20, it is possible to control seven LEDs without increasing the number of connection lines V (it goes without saying that IA can be used for information transmission other than LED lighting). When configuring a TTL circuit to further increase the noise margin, it is even better to invert the output of the six-man AND circuit 19 and transmit it. Further, even if the output of the three-person AND circuit 19 is delayed so that the D latch 21 is latched after the output of the counter 3 has been determined, the problem still exists.

According to this embodiment, as shown above, it is possible to control a plurality of LEDs using one connection line.

〔Effect of the invention〕

According to the present invention, in the parallel keyboard peripheral circuit of a keyboard-separated personal computer, it is possible to reduce the number of connecting wires between the keyboard and the computer main body, and the number of wires can be reduced to eight or less. General purpose DIN
connector.

DIN jacks can be used, making it possible to reduce the cost of LL connectors and wires. By reducing the number of connection lines V, the operability when using the keyboard separated from the computer body is improved.

Note that if the coincidence signal generation circuit 20 is incorporated into the gate array in the main body of the switchboard, there is no need to consider the cost amplifier of this part, and therefore, the increase in the number of D-latches 21, connection wires, and connector cores can be avoided. When comparing the cost of reducing the number of bt, the latter has a larger absolute value.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating an example of the integrated keyboard peripheral circuit of a conventional keyboard-separated personal computer. Figure 2 shows
1 is a block diagram of a keyboard peripheral circuit of a keyboard-separated personal computer showing an embodiment of the present invention. 1... Connection line connecting the keyboard and the computer body 2.3
... Counter 4 ... Data decoder 5 ... Keyboard matrix 6 ... Data selector 7 ... D latch 8 ... Three-state buffer 9 ・D latch 10.11.1:2 ・LED 13,
14.15... Exclusive OR circuit 16, 17
．． 18... Inverter 19... 3 person AND circuit 2o... Coincidence signal generation circuit 21... D latch

Claims (1)

[Claims] Device for transmitting and receiving mutually synchronized m focus counter data 1. The device 2 is equipped with a circuit that outputs a pulse signal only when n bits (->-) data and n bits of the m-bit counter output match, and a circuit that outputs a pulse signal only when n-bit (->-) data and n bits of the m-bit counter output match, and a circuit that outputs a pulse signal by the pulse. A circuit that latches and codes rubit data? A data transmission device characterized by comprising: