JPH0433043A - Adapter - Google Patents

Abstract

PURPOSE:To connect a peripheral device having the different timing relation of a hand-shake signal to a host computer by converting the hand-shake signal having the prescribed timing relation into the hand-shake signal of the other timing relation, and repeating the converted signal. CONSTITUTION:A timing relation changing means 11 is provided to change the timing relation between hand-shake signals A and B to be inputted to the other timing relation. Then, two pulse signals A and B having the prescribed timing relation inputted from a printer 2 are outputted after being converted to the other timing relation provided for a host computer 3. Thus, hand shaking is enabled between the host computer 3 and the printer 2 equipped with interfaces different each other.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention converts a handshake signal compliant with the Centronics specification, consisting of an /ACK signal and a BUSY signal having a predetermined timing relationship, into a handshake signal with other timing relationships. Regarding the adapter.

[Conventional technology]

Peripheral devices such as printers and plotters are generally connected to a host computer via a Centronics interface, and the /ACK and B signals have a predetermined timing relationship.
Parallel data is sent and received while checking the other party's status using a handshake signal that complies with Centronics specifications and includes a USY signal.

There are generally three types of handshake signals based on Centronics specifications, as shown in Figures 8 to 10, depending on the difference in the timing of generation between /ACK and BUSY.
Typically, printers and host computers are equipped with a Centronics interface that allows them to send and receive at least some handshake signals.

[Problem to be solved by the invention]

By the way, if there is only one type of timing relationship between handshake signals supported by the host computer and the printer, the mutual timing relationships may not match. In this case, handshake cannot be performed when exchanging data, and the printer and host computer cannot be connected. For this reason, for example, when expanding or enriching host computers or printers, etc., the types of additional equipment may be limited, or the connections between the additional equipment and existing equipment may be subject to certain restrictions, making it difficult to make effective use of the equipment. become unable.

The present invention has been made in view of the above, and converts a handshake signal having one timing relationship compliant with the Centronics specification into a handshake signal having another timing relationship, and provides a host with mutually different Centronics interfaces. The purpose is to provide an adapter that enables connection between computers and printers.

[Means to solve the problem]

In order to solve the above problems, the present invention provides two combiators that are interposed between a host combinator and a peripheral device, and have a predetermined timing relationship between the peripheral device and the host computer.
This adapter relays a handshake signal consisting of two pulse signals, and is equipped with a timing relation conversion means for changing the timing relation of the input handshake signal to another timing relation.

Note that the conversion of the timing relationship is preferably such that at least one of the two pulse signals is delayed by a predetermined time.

[Effect]

The adapter configured as described above is connected between the printer and the host computer. Two pulse signals inputted from the printer and having a predetermined timing relationship are converted into another timing relationship provided by the host computer and output.

This allows handshaking between a host computer and a printer that have mutually different interfaces.

Further, the timing relationship between the two pulse signals is converted to another timing relationship by delaying at least one of the pulse signals by a predetermined time.

〔Example〕

FIG. 1 is a configuration diagram in which an adapter according to the present invention is interposed between a printer and a host computer. In the figure, 1 is an adapter, 2 is a printer, and 3 is a host computer. Adapter 1 uses /ACK signal and BUS
It has input/output ports for each Y signal and input/output ports for a plurality of other signal lines, and is connected between the printer and the host computer with the input port facing the printer. 11 and 1
1' is a delay circuit that delays at least one of the input handshake signals (/ACK', BUSY') by a predetermined time period, which is different from the handshake signal (/ACK', BUSY'). Other timing-related handshake signals (/ACK, B
(U.S.Y.).

The delay circuit 11.11' has a fixed delay time, a CR integration circuit consisting of a resistor R and a variable pull capacitor VC as shown in FIG. It may be configured with a delay line 4. In the CR integration circuit shown in FIG. 2, the time constant is changed by changing the capacitance of the variable pull capacitor VC, and a desired delay time is set.

In addition, the delay line 4 shown in FIG. 3 is connected to the input port 11. (2) A signal input to one of ports 2 is delayed by a predetermined delay time set in advance for that port, and then output from output port 0.

Note that the input lines are switched to the input ports I□ and I2 by, for example, a dip switch.

For example, the delay amount of the delay circuit 11 is set to 0, and the delay circuit 11'
By setting the delay amount to a predetermined value, adapter 1
from the handshake signal at timing A to timing B
Alternatively, it can be an adapter that converts it into a C handshake signal. That is, the delay amount of the delay circuit 11' is t
When set to Dl (=t1 + t2), the handshake signal (/ACKI,
BUSYI) is the handshake signal at timing B (/
ACK2. BUSY2). Therefore, this adapter 1 enables connection between a printer that outputs a handshake signal at timing A and a host computer that receives and receives a handshake signal at timing B.

Furthermore, the delay amount of the delay circuit 11' is io2 (=t□+ta
), the handshake signal at timing A (/AC
K.I.

BUSYI) is the handshake signal at timing C (/
ACK2. BUSY2).

Also, for example, by setting the delay amount of the delay circuit 11' to 0 and setting the delay amount of the delay circuit 11 to a predetermined value, the adapter 1 is converted from a handshake signal at timing C to a handshake signal at timing A or B. It can be used as an adapter.

That is, when the delay amount of the delay circuit 11 is set to tDl (=t3+t1) as shown in FIG. 5, the handshake signal at timing C (/ACK3°BUSY3) becomes the handshake signal at timing A (/ACKI, BUSY3)
SYI) and further converts the delay amount of the delay circuit 11 to
2 (=t3 t2), the handshake signal at timing C (/ACK3.BUSY3) becomes the handshake signal at timing B (/ACK2.BUSY2).
) is converted to

Also, by setting the delay amount of either the delay circuit 11 or the delay circuit 11' to 0 and setting the delay amount of the other to a predetermined value, the adapter 1 can be changed from the handshake signal at timing B to the timing A or C. It can be an adapter that converts the handshake signal. In other words, kettle 6
As shown in the figure, when the delay amount of the delay circuit 11' is set to 0 and the delay amount of the delay circuit 11 is set to tDl (=t1+tz), the handshake signal (/ACK
2. BUSY2) is converted into a handshake signal (/ACKI, BUSYI) at timing A, and the delay circuit 11
The delay amount of the delay circuit 11' is set to 0, and the delay amount of the delay circuit 11' is set to2.
(=ta t2) Then, the handshake signal at timing B (/ACK2°BUSY2) is converted to the handshake signal at timing C (/ACK3.BUSY3).

Incidentally, two delay circuits for the /ACK signal and the BUSY signal may be arranged in parallel between the respective input/output ports for the /ACK signal and the BUSY signal, and the circuits may be switched.

FIG. 7 is a circuit configuration diagram showing an embodiment for this purpose.

In the figure, 51, 52, 51' and 52' are delay circuits having the same structure as the delay circuit 11, 11'. Further, SW is connected to the /A CK' signal input and the delay circuit 5.
1.52 and the connection between the BUSY' signal input and the delay circuits 51' and 52', respectively.

For example, each delay amount of the delay circuits 51 and 52 is set to 0, and each delay amount of the delay circuits 51' and 52' is set to tDl (
By setting tD2 (=t1+t2) and tD2 (=t1+ta), the adapter 5 can be configured as an adapter capable of converting a handshake signal at timing A to a handshake signal at either timing B or C. In other words, when the common terminals (c, c') are connected to the terminals (a, a), only the BUSYI signal is tDl ("tl
+t2), and the handshake signal (/ACKI.+t2) at timing A is delayed as shown in FIG.

BUSYI) is the handshake signal at timing B (/
ACK2. BUSY2). Moreover, when the common terminals (c, c') are connected to the terminals (b, b'), only the BUSYI signal is tD 2 (=tl +
t3), and the handshake signal (/ACKI, BUSYI) at timing A is delayed as shown in Figure 4.
is the handshake signal at timing C (/ACK3.B
USY3).

Also, each delay amount of the delay circuits 51 and 52 is tD□
(=ta +t1), tDz' (=t:1
-t2) and setting each delay amount of the delay circuits 51' and 52' to 0, the adapter 5 can change the handshake signal at timing C to the handshake signal at either timing A or B. Can be an adapter. In this case, the output handshake signal (
/ACK, BUSY) are the common terminals of the switch SW (
c, c') is connected to the terminal (a, a'), the terminal (a.

a'), it becomes a handshake signal (/ACKI, BUSYI) at timing A, and the terminals (b, b
), it becomes a handshake signal (/ACK2.BUSY2) at timing B (see Figure 5).
.

In addition, each delay amount of the delay circuits 51 and 52 is tDx.
(=tl +t2), set to 0, and set each delay amount of the delay circuits 51' and 52' to OS tD2 (=t3
tz) by setting the adapter 5 to timing B.
The adapter can switch from the handshake signal at timing A to the handshake signal at timing A or C. In this case, the handshake signal (/ACK) is output.

BUSY) is the common terminal (C9
C') is connected to the terminal (a, a'), the handshake signal (/ACKI, BUSYI) at timing A
When connected to the terminals (b, b'), the handshake signal (/ACK3.BUSY3) at timing C is generated.
(See Figure 6).

In this embodiment, by changing the switch SW, it is possible to convert and output handshake signals with different timing relationships, so the printer can be easily and easily connected to any host computer that has a Centronics interface. can do.

Note that the amount of delay of each delay circuit for the /ACK signal and the BUSY signal for converting a handshake signal having a predetermined timing relationship into a handshake signal having a different timing relationship is not limited to the above embodiment, and may be varied. A combination of these can be adopted.

〔Effect of the invention〕

As explained above, according to the present invention, a handshake signal having a predetermined timing relationship sent from a peripheral device to a host computer is converted into a handshake signal having another timing relationship and then relayed. Even when the timing relationship of the handshake signals supported by the peripheral device is different from the timing relationship of the handshake signals supported by the host computer, the peripheral device can be simply and easily connected to the host computer. . Therefore, by using the adapter according to the present invention, when adding peripheral devices such as printers or host computers, or changing the system, it is possible to effectively utilize equipment at low cost.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an adapter according to the present invention interposed between a printer and a host computer, Fig. 2 is a diagram showing one embodiment of a delay circuit, and Fig. 3 is a diagram showing another embodiment of the delay circuit. 4 is a time chart for explaining the operation of converting the timing relationship of handshake signals from timing A to timing B, C, and FIG. 5 is a time chart for explaining the operation of converting the timing relationship of handshake signals from timing B to timing A, FIG. 6 is a time chart for explaining the operation of converting the handshake signal from timing C to timing A and B. FIG. 7 is a time chart for explaining the operation of converting the timing relationship of the handshake signal from timing C to timing A and B. 8 to 10 are diagrams showing the circuit configuration of the second embodiment of the adapter according to
The diagram shows the /ACK signal and BUSY according to Centronics specifications.
3 is a time chart showing a timing relationship with a signal. 1.5...Adapter, 2...Printer, 3...Host computer, 4...Delay line, 11.1
1', 51.51', 52.52'...Delay circuit, R...Resistor, VC...Variable pull capacitor. Patent applicant Agent: Sanda Kogyo Co., Ltd.
Patent Attorney Etsushi Kotani Patent Attorney Chief 1) Masamukai Patent Attorney Takao Ito

Claims (1)

[Claims] 1. An adapter that is interposed between a host computer and a peripheral device and relays a handshake signal consisting of two pulse signals having a predetermined timing relationship and sent from the peripheral device to the host computer. An adapter characterized in that it is provided with a timing relationship converting means for changing the timing relationship of the input handshake signal to another timing relationship. 2. The adapter according to claim 1, wherein the timing relationship conversion means comprises delay means for delaying at least one of the two pulse signals by a predetermined time.