JPH08202653A - Parallel signal transmission equipment - Google Patents

Abstract

PURPOSE: To apply a parallel signal transmission equipment to a transmission line whose signal transmission direction is unidirectional or a half duplex transmission line, to prevent malfunction, and to correctly correct inter-signal skew without spoiling the efficiency of original signal transmission. CONSTITUTION: This transmission equipment is equipped with a means 16 which sends a test signal to all lines of a transmission line 13 in the same timing on the signal transmission side and means 171 -17n which measure and store the times from a test signal reception point of time to the reception of test signals from all the lines of the transmission line 13 by the lines of the transmission line 13 on the signal reception side and delays the signals transmitted through the transmission line 13 by the stored times to correct the inter-signal skew.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel signal transmission device having a function of correcting a signal skew generated in a parallel signal transmission line such as a SCSI bus.

[0002]

2. Description of the Related Art When a plurality of signals are transmitted in parallel via a transmission line, a skew between the signals occurs during the transmission of the plurality of signals. Japanese Unexamined Patent Publication No. 1-149154 discloses a data transfer system in which a signal-to-device skew is corrected in a parallel interface in which signals are exchanged between opposing devices. In this data transfer method, the transfer path is a full-duplex configuration having bidirectional independent lines for each signal. Opposing devices have a master-slave relationship, and the main device performs most of the control.

In the operation of this data transfer system, first, a test signal is transmitted from the main device to the slave device using one of the lines. The slave device returns the received test signal to the master device side through all the lines. The main unit detects the delay between signals in the signal transmission from the slave unit to the main unit by measuring the delay amount for each line of the received test signal and corrects it. Next, a test signal is transmitted from the master device to the slave device for each line. The slave device returns the received signal to the master device for each line. The main device detects the signal-to-signal skew in the signal transmission from the main device to the slave device from the delay amount of the received signal for each line, and corrects it.

[0004]

In the above-mentioned data transfer method, since the signal-to-signal skew is detected and corrected by the return signal from the opposite device, when the signal transmission direction of the transmission line is only one direction, This is not applicable when the signal has a half-duplex configuration and each signal shares one line in a time division manner and transmits in both directions. In addition, if the test signal transmission side does not start the test signal transmission after the test signal reception side is ready to receive the test signal, a malfunction occurs and the test signal delay amount cannot be measured correctly. The structure is not described in JP-A-1-149154. Further, it takes at least two round trips of the test signal through the transmission path to perform bidirectional signal skew correction.
This may impair the original efficiency of signal transmission.

The present invention can be applied to the case where the signal transmission direction of the transmission line is only one direction or the case where the transmission line has a half-duplex configuration, and it is possible to prevent malfunction and improve the original signal transmission efficiency. An object of the present invention is to provide a parallel signal transmission device that can correct skew between signals without damage.

[0006]

In order to achieve the above object, the invention according to claim 1 is a parallel signal transmission apparatus for transmitting a plurality of signals in parallel via a transmission line, and a test signal is provided on the signal transmission side. Generating a test signal and transmitting the test signal to all the lines of the transmission path at the same timing, and the transmission from the time when the test signal is received for each line of the transmission line at the signal receiving side. Measuring and storing the time until the test signal is received from all the lines of the transmission line, and delaying each of the plurality of signals transmitted by each line of the transmission line by the stored time. According to the aspect of the invention, there is provided inter-signal skew correction means for correcting inter-signal skew that occurs during transmission of the plurality of signals.

According to a second aspect of the present invention, there is provided a parallel signal transmission device for transmitting a plurality of signals in parallel via a transmission line,
The test signal transmitting side transmits a request signal to the test signal receiving side to inform the test signal transmitting side before transmitting the test signal, and the test signal receiving side receives the request signal and transmits the test signal. After returning to the test signal transmission side after preparing to receive the test signal, the test signal transmission side confirms the reception of the response signal and then sends the test signal to all lines of the transmission line at the same timing. Signal transmission / reception means for signal skew correction to be transmitted, and from the time of receiving the test signal for each line of the transmission line at the test signal receiving side until receiving the test signal from all the lines of the transmission line The signal generated during the transmission of the plurality of signals by measuring and storing the time, and delaying the plurality of signals transmitted by each line of the transmission path by the stored time. Inter-skew It is characterized in that a signal skew correcting means for correcting.

According to a third aspect of the present invention, in a parallel signal transmission device in which a plurality of signals are transmitted in parallel via a transmission line, and the transmission line is half-duplex, the parallel signal transmission device is provided on both sides of the transmission line. Before sending the test signal to the side, it sends a request signal to notify the sending of the test signal, receives the request signal from the other party, sends back a response signal to the other party, and receives the response signal from the other party. Two request / response signal transmission / reception means and a request / response signal transmission / reception means provided on both sides of the transmission path and provided on the same side of the transmission path among the two request / response signal transmission / reception means.
The test signal is transmitted to all the lines of the transmission line at the same timing by receiving the response signal of the response signal transmitting / receiving means, and from the point of receiving the test signal for each line of the transmission line, from all the lines of the transmission line. The time until the test signal is received is measured and stored, and the plurality of signals transmitted by each line of the transmission path are delayed by the stored time respectively, thereby Two signal-to-signal skew correction means for correcting signal-to-signal skew generated during signal transmission are provided, and the order of operation of the two request / response signal transmission / reception means and the two signal-to-signal skew correction means is determined in advance. It is characterized by that.

According to a fourth aspect of the present invention, in a parallel signal transmission device in which a plurality of signals are transmitted in parallel via a transmission line, and the transmission line is full duplex, the parallel signal transmission device is provided on both sides of the transmission line. Before sending the test signal to the side, it sends a request signal to notify the sending of the test signal, receives the request signal from the other party, sends back a response signal to the other party, and receives the response signal from the other party. Two request / response signal transmission / reception means and a request / response signal transmission / reception means provided on both sides of the transmission path and provided on the same side of the transmission path among the two request / response signal transmission / reception means.
The test signal is transmitted to all the lines of the transmission line at the same timing by receiving the response signal of the response signal transmitting / receiving means, and from the point of receiving the test signal for each line of the transmission line, from all the lines of the transmission line. The time until the test signal is received is measured and stored, and the plurality of signals transmitted by each line of the transmission path are delayed by the stored time respectively, thereby Two signal-to-signal skew correction means for correcting signal-to-signal skew generated during signal transmission, wherein the two request / response signal transmission / reception means transmit / receive the request signal when one of the two request / response signal transmission / reception means transmits the request signal. The other of the signal transmitting / receiving means also transmits the request signal so that the two request / response signal transmitting / receiving means and the two signal skew correcting means simultaneously perform the same series of operations in both directions. It is characterized in that it has a Migihitsuji.

The invention of claim 5 is the invention of claims 1, 2, and 3.
Alternatively, in the parallel signal transmission device according to the fourth aspect, the means performs a series of operations at least when the power is turned on.

The invention according to claim 6 is the same as claims 1, 2 and
In the parallel signal transmission device described in item 3, 4 or 5, the means repeats a series of operations at predetermined time intervals.

The invention according to claim 7 is the invention according to claims 2, 3,
In the parallel signal transmission device according to 4, 5, or 6, the signal transmitting / receiving unit for skew correction between signals or the request / transmission means
The response signal transmitting / receiving means confirms that the transmission line is in an idle state and starts transmitting the request signal and the response signal.

The invention according to claim 8 is the invention according to claim 2, 3,
In the parallel signal transmission device according to 4, 5, 6 or 7,
When the request signal is received, the signal skew correction signal transmitting / receiving means or the request / response signal transmitting / receiving means blocks the test signal from the transmission path and does not transmit the signal to the outside. .

[0014]

According to the first aspect of the present invention, the test signal transmitting means generates the test signal on the signal transmitting side and transmits the test signal to all lines of the transmission line at the same timing. Then, the signal-to-signal skew correction means measures and stores the time from the reception of the test signal for each line of the transmission line on the signal receiving side to the reception of the test signal from all the lines of the transmission line,
By delaying each of the plurality of signals transmitted through each line of the transmission path by the stored time, the signal-to-signal skew occurring during the transmission of the plurality of signals is corrected.

According to another aspect of the present invention, the signal transmitting / receiving means for inter-signal skew correction requests the transmission side of the test signal to notify the reception side of the test signal of the transmission of the test signal to the reception side of the test signal. After sending the signal, the test signal receiving side receives the request signal and prepares to receive the test signal, then returns the response signal to the test signal transmitting side, and the test signal transmitting side receives the response signal. After confirming, the test signal is transmitted to all lines of the transmission line at the same timing. And
The signal-to-signal skew correction means measures and stores the time from the reception of the test signal for each line of the transmission line on the reception side of the test signal to the reception of the test signal from all the lines of the transmission line, By delaying each of the plurality of signals transmitted through each line of the transmission path by the stored time, the signal-to-signal skew occurring during the transmission of the plurality of signals is corrected.

According to the third aspect of the present invention, the two request / response signal transmitting / receiving means provided on both sides of the transmission path transmit a request signal for notifying the other side of the transmission of the test signal before transmitting the test signal. Then, the request signal from the other party is received, the response signal is sent back to the other party, and the response signal from the other party is received. The two signal skew correction means provided on both sides of the transmission line are tested by receiving response signals from the request / response signal transmission / reception means provided on the same side of the transmission line among the two request / response signal transmission / reception means. The signal is sent to all the lines of the transmission line at the same timing, and the time from when the test signal is received to each line of the transmission line until the test signal is received from all the lines of the transmission line is measured and stored. , The signal-to-signal skew generated during the transmission of the plurality of signals is corrected by delaying the plurality of signals transmitted through each line of the transmission path by the stored time. These two request / response signal transmitting / receiving means and the two signal skew correcting means operate in a predetermined operation order.

According to another aspect of the invention, the two request / response signal transmitting / receiving means provided on both sides of the transmission line transmit a request signal to the other side to notify the transmission of the test signal before transmitting the test signal. Then, the request signal from the other party is received, the response signal is sent back to the other party, and the response signal from the other party is received. The two signal skew correction means provided on both sides of the transmission line are tested by receiving response signals from the request / response signal transmission / reception means provided on the same side of the transmission line among the two request / response signal transmission / reception means. The signal is sent to all the lines of the transmission line at the same timing, and the time from the point of receiving the test signal to the reception of the test signal from all the lines of the transmission line is measured and stored. Then, the signal-to-signal skew that occurs during the transmission of the plurality of signals is corrected by delaying the plurality of signals transmitted through each line of the transmission path by the stored time. Two
When one of the two request / response signal transmitting / receiving means transmits the request signal, the other of the two request / response signal transmitting / receiving means also transmits the request signal so that the two request / response signal transmitting / receiving means and the two signal skew correcting means Simultaneously perform the same series of operations in both directions.

In the invention described in claim 5, claims 1, 2,
In the parallel signal transmission device described in 3 or 4, the means performs a series of operations at least when the power is turned on.

According to the invention of claim 6, claims 1, 2,
In the parallel signal transmission device described in 3, 4, or 5, the means repeats a series of operations at predetermined time intervals.

According to the invention of claim 7, claims 2, 3,
In the parallel signal transmission device described in 4, 5, or 6, the signal transmission / reception means for signal skew correction or the request / response signal transmission / reception means confirms that the transmission path is in an idle state and starts transmission of the request signal and the response signal. To do.

According to the invention described in claim 8,
In the parallel signal transmission device according to 4, 5, 6 or 7,
Upon reception of the request signal, the signal transmission / reception means for signal skew correction or the request / response signal transmission / reception means cuts off the test signal from the transmission path so that it is not transmitted to the outside.

[0022]

FIG. 2 shows an example of a system configuration using a parallel signal transmission apparatus (hereinafter simply referred to as a transmission apparatus) according to an embodiment of the invention described in claims 1, 2, 5-8. Transmission device 11, 12
Are provided on both sides of the transmission line 13, and are connected to the terminal devices 14, 15
Connected by an interface connector. The terminal device 14 is, for example, a host computer, and the terminal device 15 is, for example, a printer. Transmission device 11, 12
Performs signal transmission between the terminal devices 14 and 15 and the transmission path 13.

FIG. 1 shows a configuration example of the transmission devices 11 and 12. The transmission devices 11, 12 are claimed in claims 1, 2, 5-8.
It is an embodiment of the described invention, and has a control circuit 16 and signal transmission circuits 17 _{1 to} 17 _n . The control circuit 16 is a part that transmits and receives request signals and response signals and generates test signals. The signal transmission circuits 17 _{1 to} 17 _n are the terminal devices 14 and 1
5 and the lines 13 _{1 to} 13 _n of the transmission line 13 are relayed for transmission of a plurality of signals, and are provided for each signal.

FIG. 3 shows an example of the configuration of the control circuit 16 in the transmission device of the transmission devices 11 and 12 which transmits the test signal. The resistor 18 and the capacitor 19 are DC power source Vc
It is connected in series between c and the ground point, and the connection point of the resistor 18 and the capacitor 19 is connected to the input side of the buffer 20 having a hysteresis characteristic. When the power is turned on,
The capacitor 19 is charged from the power supply Vcc through the resistor 18, and the input voltage of the buffer 20 gradually rises.
When the input voltage of the buffer 20 exceeds a predetermined level, the output voltage of the buffer 20 transitions to a high level (hereinafter referred to as H). At this time, if the output signal S6 of the timer 21 described later is at a low level (hereinafter referred to as L), the AND circuit 22 receives the output signal of the buffer 20 and the output signal S6 of the timer 21 is output by the inverter 23. The output signal S1 becomes H by being inverted and input and taking the AND of these.

The rising transition detection circuit 24 detects the transition of the input signal S1 from the AND circuit 22 from L to H, and the output signal S2 changes from L to H. On the other hand, when the transmission path idle detection circuit 25 detects that there is no transmission signal between the terminal devices 14 and 15 and the transmission path 13 and the transmission path 13 is in the idle state, the output signal S3 changes from L to H. become. The AND circuit 26 takes the AND of the input signal S2 from the rising transition detection circuit 24 and the input signal S3 from the transmission path idle detection circuit 25 and outputs it as a request signal. Therefore, the request signal does not become H if any _{one of the} lines 13 _{1 to} 13 _n of the transmission line 13 is transmitting a signal. The request signal is a signal notifying the transmission of the test signal before transmitting the test signal. The transmission path idle detection circuit 25 is an AND circuit 26.
Output signal S3 during the period when the request signal from H is H.
Is held at H. The request signal from the AND circuit 26 is transmitted via the control signal line to the control circuit 16 in the transmission device of the transmission devices 11 and 12 which receives the test signal.

The AND circuit 27 receives the request signal from the AND circuit 26, and the control circuit 16 in the transmission device of the transmission devices 11 and 12 which receives the test signal.
The response signal from is taken and these ANDs are taken. In response to the request signal from the AND circuit 26, the test signal generation circuit 28 returns a response signal from the control circuit 16 in the transmission device on the side of the transmission devices 11 and 12 that receives the test signal, and the request signal and the response signal are sent simultaneously. Become H and AND circuit 2
When the input signal S4 from 7 becomes H, that is, when the reception of the response signal is confirmed, the output of the test signal is started. This test signal is sent to all the lines 13 _{1 to} 13 _n of the transmission line 13 at the same timing.

The end detection circuit 29 detects that the response signal from the control circuit 16 in the transmission device on the side receiving the test signal of the transmission devices 11 and 12 changes from H to L and outputs the output signal S5 from L to H. To Rising transition detection circuit 2
4 is reset when the input signal S5 from the end detection circuit 29 becomes H, and the output signal S2 becomes L. As a result, the request signal from the AND circuit 26 becomes L. The end detection circuit 29 receives the request signal from the AND circuit 26 as L
Then, the output signal S5 goes low. Therefore, the signal S5 only goes high temporarily.

The timer 21 is activated when the input signal S5 from the end detection circuit 29 becomes H, and the output signal S6 changes from L to H when a predetermined time has elapsed after that. However,
Since the timer 21 resets itself when the output signal S6 goes high, the signal S6 goes low immediately. The output signal S6 of the timer 21 is inverted by the inverter 23 and input to the AND circuit 22, but the output signal of the buffer 20 is already H and does not change. Therefore, the output signal S1 of the AND circuit 22 rises again. Occurs, which causes the same operation as described above to be repeated.

FIG. 4 shows an example of the configuration of the control circuit 16 in the transmission device of the transmission devices 11 and 12 which receives the test signal. The control circuit 16 includes a transmission line idle detection circuit 30,
It has a delay setting end detection circuit 31, an inverter 32, and an AND circuit 33. The transmission line idle detection circuit 30 is exactly the same as the transmission line idle detection circuit 25. However,
The response signal from the AND circuit 33 is input to the transmission path idle detection circuit 30 instead of the request signal.

The delay setting end detection circuit 31 is used in the transmission device 1.
A request signal from the control circuit 16 in the transmission device on the transmission side of the test signal of 1 and 12 is input, the request signal becomes H, and signals from all the lines 13 _{1 to} 13 _n of the transmission line 13 ( When it is detected that the test signal) has been received, the output signal S8 is set to H. The AND circuit 33 receives the output signal S8 of the delay setting end detection circuit 31 after being inverted and input by the inverter 32, and requests from the control circuit 16 in the transmission device of the transmission devices 11 and 12 that transmits the test signal. Signal and output signal S of the transmission path idle detection circuit 30
7 is input, and these ANDs are taken and output as a response signal. Therefore, when the request signal becomes H, this control circuit confirms that there is no transmission signal of all the lines 13 _{1 to} 13 _n of the transmission line 13 and sets the response signal to H, that is, the test signal. The response signal is set to H after preparation for reception. The response signal from the AND circuit 33 becomes L when the output signal S8 of the delay setting end detection circuit 31 becomes H. The response signal from the AND circuit 33 is transmitted via the control signal line to the control circuit 16 in the transmission device of the transmission devices 11 and 12 that transmits the test signal.

FIG. 5 shows the signal transmission circuits 17 ₁ to 17 ₁ -in the transmission device of the transmission devices 11 and 12 which transmits the test signal.
17 _n shows an example. This signal transmission circuit 17 _{1 to} 17
_n is an AND circuit 34, 35 and an inverter 36, respectively.
It also has an OR circuit 37, and switches the signal sent from the terminal device to the transmission line 13 and the test signal and sends it to the transmission line 13.

That is, the signal sent from the terminal device to the transmission line 13 is output from the inverter 36 when the request signal from the control circuit 16 in the transmission device of the transmission devices 11 and 12 that transmits the test signal is L. The output signal passes through the AND circuit 34 and the OR circuit 37 and is sent to the transmission path 13. Further, when the request signal from the control circuit 16 in the transmission device on the side transmitting the test signal of the transmission devices 11 and 12 becomes H, the output signal of the inverter 36 becomes L.
Then, the signal from the terminal device to the transmission path 13 is blocked by the AND circuit 34. At the same time, the control circuit 16 in the transmission device of the transmission devices 11 and 12 that transmits the test signal
From the control circuit 16 in the transmission device that transmits the test signal among the transmission devices 11 and 12, passes through the AND circuit 35, and is transmitted to the transmission path 13 through the OR circuit 37. .

FIG. 6 shows the signal transmission circuits 17 ₁ to 17 ₁ -in the transmission device on the side receiving the test signal among the transmission devices 11 and 12.
17 _n shows an example. This signal transmission circuit 17 _{1 to} 17
_n is the skew correction circuit 38 and the inverter 39, respectively.
And AND circuit 40. Control circuit 1 in the transmission device of the transmission devices 11 and 12 that receives the test signal
The response signal from 6 is input to the skew correction circuit 38, inverted by the inverter 39, and input to the AND circuit 40. Signals (test signals) from the lines 13 _{1 to} 13 _n of the transmission line 13 are delayed by the skew correction circuit 38,
When the response signal becomes H, the skew correction circuit 38 transmits the transmission line 1
The delay amount with respect to the signal from 3 is gradually increased. Then, the skew correction circuit 38 fixes the delay amount for the signal from the transmission line 13 at the delay amount at the time when the input signal S8 from the delay setting end detection circuit 31 becomes H. When the response signal becomes L, the signal from the transmission line 13 is delayed by the fixed delay amount in the skew correction circuit 38, and is output to the terminal device through the AND circuit 40 by the output signal of the inverter 39.

FIG. 7 shows a configuration example of the skew correction circuit 38. The skew correction circuit 38 includes a reset circuit 41, a counter 42, a shift register 43, a decoder 44, and a multiplexer 45. When the reset circuit 41 receives the response signal from the control circuit 16 in the transmission device of the transmission devices 11 and 12 which receives the test signal, the reset circuit 41 temporarily sets the output signal S10 to H. When the input signal S10 from the reset circuit 41 is L, the counter 42 is input from the start of receiving the signal from the transmission path 13 until the input signal S8 from the delay setting end detection circuit 31 becomes H. By counting the clock signals, all the lines 13 ₁ to ₁ of the transmission line 13 from the time when the test signal is received.
The time from the reception of the test signal from 3 _n is measured and stored, and the count value is stored as m-bit binary data S11.
Output as Further, the counter 42 is reset when the input signal S10 from the reset circuit 41 becomes H and resets all the output signals S11 to 0.

The shift register 43 sequentially delays the signal from the transmission path 13 in synchronization with the clock signal, and outputs the sequentially delayed signal S12 in p bits in parallel. The decoder 44 decodes the binary data S11 from the counter 42 and sets only the bit corresponding to the binary data S11 in the p-bit output signal S13 to H level. The multiplexer 45 outputs H of the output signal S13 of the decoder 44 out of the p-bit signal S12 from the shift register 43.
Output signal S9 by selecting the one corresponding to the bit
Output as

Transmission devices 11, 12 in this system
Is an embodiment of the invention according to claim 1, wherein in a parallel signal transmission device for transmitting a plurality of signals in parallel via the transmission path 13, a test signal is generated at the signal transmission side to generate the test signal. A test signal generating circuit 28 as a test signal transmitting means for transmitting to all the lines 13 _{1 to} 13 _n of the transmission line 13 at the same timing, and each line 13 _{1 of the} transmission line 13 at the signal receiving side.
Every 13 to 13 _n , the time from the reception of the test signal to the reception of the test signal from all the lines 13 _{1 to} 13 _{n of} the transmission line 13 is measured and stored, and each line 13 ₁ to ₁ of the transmission line 13 is stored.
A signal transmission circuit as an inter-signal skew correction means for correcting the inter-signal skew generated during the transmission of the plurality of signals by delaying each of the plurality of signals transmitted by 3 _n by the stored time. Since the skew correction circuit 38 including the reset circuit 41, the counter 42, the shift register 43, the decoder 44, and the multiplexer 45, and the signal transmission circuit (including the inverter 39 and the AND circuit 40) are provided, the signal transmission direction of the transmission path. It can also be applied to the case where is only one direction.

Further, the transmission device 1 in this system
1 and 12 are embodiments of the invention according to claim 2, wherein in the parallel signal transmission device for transmitting a plurality of signals in parallel via the transmission line 13, the test signal transmission side is the test signal reception side. To the test signal before sending the test signal, the test signal receiving side receives the request signal and prepares to receive the test signal. The test signal is returned to the transmission side, and the test signal transmission side confirms the reception of the response signal before transmitting the test signal to the transmission line 13.
Control circuit 16 in the transmission devices 11 and 12 shown in FIGS. 3 and 4 as signal skew correction signal transmitting / receiving means for transmitting to all the lines 13 _{1 to} 13 _n at the same timing.
And each line 13 _{1 of the} transmission line 13 on the receiving side of the test signal
The time from the reception of the test signal every 13 _n to the reception of the test signal from all the lines 13 _{1 to} 13 _{n of} the transmission line 13 is measured and stored, and each line 13 _{1 to} 13 _{n of the} transmission line 13 is measured and stored.
The signal transmission circuit (reset circuit) as a signal-to-signal skew correction means for correcting the signal-to-signal skew that occurs during the transmission of the plurality of signals by delaying the plurality of signals transmitted in 41, a counter 42, a shift register 43, a decoder 44, and a skew correction circuit 38 composed of a multiplexer 45, an inverter 39, and a signal transmission circuit having an AND circuit 40).
Since the test signal receiving side receives the request signal and prepares to receive the test signal, the response signal is returned to the test signal transmitting side to prevent malfunction.

Further, the transmission device 1 in this system
1 and 12 are the embodiments of the invention described in claim 5, and perform a series of operations for correcting the skew between signals at least when the output signal of the buffer 20 transits to H at the time of turning on the power source. The signal-to-signal skew can be reliably corrected without shifting the hand, and highly reliable signal transmission can be realized.

Further, the transmission device 1 in this system
1 and 12 are the embodiments of the invention described in claim 6, in which the output signal S5 of the end detection circuit 29 becomes H and the timer 2
1 is activated and the output signal S6 of the timer 21 is input to the rising transition detection circuit 24 via the inverter 23, whereby the rising transition detection circuit 24 is reset and a series of signals for correcting the skew between signals is output. Since the operation is repeated every predetermined time, it is possible to suppress the occurrence of signal-to-signal skew even if the signal-to-signal skew changes over time due to environmental temperature and power supply voltage fluctuations, and signal transmission with excellent environmental resistance. Can be realized.

Further, the transmission device 1 in this system
Reference numerals 1 and 12 are embodiments of the invention described in claim 7, and the control circuit 16 in the transmission device 11 or 12 as the signal skew correction signal transmitting / receiving means or request / response signal transmitting / receiving means has a free transmission path. Since the transmission path vacancy detection circuits 25 and 30 confirm that the status is in the state and start transmitting the request signal and the response signal, even if some signal transmission occurs at the time to start the inter-signal skew correction operation. In addition, it is possible to wait until it is completely completed, and the signal-to-signal skew can be correctly corrected without impairing the original signal transmission efficiency.

Further, the transmission device 1 in this system
Reference numerals 1 and 12 are the embodiments of the invention described in claim 8, wherein the inter-signal skew correction signal transmission / reception means or the request / response signal transmission / reception means receives the request signal, and the transmission line 1
AND circuit 34 and inverter 36
Therefore, it is possible to prevent the system from being damaged by the test signal and to secure the reliability of the system because the test signal prevents the system from transmitting to the outside.

FIG. 8 shows a control circuit in an example of a system configuration using the transmission device according to the third embodiment of the invention. In this system, signals are bidirectionally transmitted between the host computer 14 and the printer 15, and the transmission line 13
This is an example of the case of a half-duplex configuration. Transmission device who transmits a request signal earlier, for example, the signal transmission circuit 17 ₁ to 17 _n in a transmission device 11, a signal transmission circuit in the transmission apparatus 12 of the person who transmits a request signal later 17 ₁ to 17 _n
5 and FIG. 6 are used respectively to perform transmission / reception of a request signal, a test signal, a response signal, and signals from the terminal devices 14 and 15 to perform inter-signal skew correction operation. 3 and 4 are used for the control circuit 16 in the transmission device 11, and those shown in FIGS. 4 and 8 are used for the control circuit 16 in the transmission device 12. The request signal and the test signal are exchanged with each other.

In the control circuit 16 in this transmission device 12, in the control circuit shown in FIG. 3, the timer 21, the inverter 23, the transmission path idle detection circuit 25, and the AND circuit 2 are provided.
2, 26, the buffer 20, the resistor 18, and the capacitor 19 are omitted, and the request signal from the transmission device 11 is transmitted to the inverter 4
Inverted at 6, the signal is input to the rising transition detection circuit 24 as the input signal S1 and the output signal of the rising transition detection circuit 24 is transmitted as it is as a request signal to the control circuit 16 of the transmission device 11 via the control signal line. Therefore, the rising transition detection circuit 24 in the transmission device 12
The request signal from H becomes H after the request signal from the transmission device 11 becomes L.

Transmission devices 11, 12 in this system
Is an embodiment of the invention as set forth in claim 3, wherein the transmission line 13
A request signal is provided on both sides of the device to notify the other party of the test signal transmission before the test signal is transmitted, the request signal from the other party is received, and a response signal is sent back to the other party. The control circuit including the rising transition detection circuit 24 and the test signal generation circuit 28 shown in FIGS. 3 and 8 as two request / response signal transmitting / receiving means for receiving the response signal from Of the two request / response signal transmission / reception means, the request signal is received by the request / response signal transmission / reception means provided on the same side of the transmission path 13, and the test signal is transmitted to all the lines 13 _{1 to} 13 _n of the transmission path 13 at the same timing. All the lines 13 ₁ of the transmission line 13 from the time when the test signal is transmitted and the test signal is received for each of the lines 13 _{1 to} 13 _{n of the} transmission line 13.
The time from the reception of the test signal up to 13 _n is measured and stored, and the plurality of signals transmitted through the lines 13 _{1 to} 13 _n of the transmission line 13 are delayed by the stored time. As a result, a signal transmission circuit (a skew composed of a reset circuit 41, a counter 42, a shift register 43, a decoder 44, and a multiplexer 45) as two inter-signal skew correction means for correcting inter-signal skew generated during transmission of a plurality of signals. A signal transmission circuit including a correction circuit 38, an inverter 39, and an AND circuit 40), and the operation order of the two request / response signal transmission / reception means and the two signal skew correction means is determined in advance. It is also applicable when the road has a half-duplex configuration.

Further, in an example of a system configuration using the transmission device of the embodiment of the invention described in claim 4, a signal is transmitted bidirectionally between the host computer 14 and the printer 15, and the transmission line 13 has all two lines. This is an example in the case of a heavy structure. In this system, the signal transmission circuit 17 ₁ to 17 _n in a transmission device 11, the signal transmission circuit 17 ₁ to 17 _n in the transmission device 12, FIG. 5 and to each other request signal both are respectively used the one shown in FIG. 6, Test signals, response signals, and signals from the terminal devices 14 and 15 are transmitted and received to perform skew correction operation between signals. 3 and 4 are used for the control circuit 16 in the transmission device 11, and the inverter 46 is omitted in the control circuit 16 in the transmission device 12 shown in FIGS. 4 and 8. Then, the request signal from the transmission device 11 is directly input to the rising transition detection circuit 24 as the input signal S1. Therefore, when the control circuit 16 of the transmission device 12 receives the request signal from the transmission device 11, subsequently, the control circuit 16 itself also transmits the request signal to the transmission device 11 to start a series of operations for correcting the signal skew. To do.

Transmission devices 11, 12 in this system
Is an embodiment of the invention as set forth in claim 4, wherein the transmission line 13
A request signal is provided on both sides of the device to notify the other party of the test signal transmission before the test signal is transmitted, the request signal from the other party is received, and a response signal is sent back to the other party. A control circuit 1 including a rising transition detection circuit 24 and a test signal generation circuit 28 shown in FIGS. 3 and 8 as two request / response signal transmitting / receiving means for receiving a response signal from
6 and the test signal of the transmission path 13 by receiving the response signal of the request / response signal transmission / reception means provided on the same side of the transmission path 13 among the two request / response signal transmission / reception means provided on both sides of the transmission path 13. All lines 13 _{1 to} 13 _n are transmitted at the same timing, and a test signal is received for each line 13 _{1 to} 13 _{n of the} transmission line 13 from the time when the test signal is received.
The time from _{1 to} 13 _n until the test signal is received is measured and stored, and a plurality of signals transmitted by each line of the transmission line 13 are delayed by the stored time, respectively. A signal transmission circuit (a skew correction circuit 38 including a reset circuit 41, a counter 42, a shift register 43, a decoder 44, and a multiplexer 45) as two signal-to-signal skew correction means for correcting the signal-to-signal skew generated during the transmission of the signal. , An inverter 39 and a signal transmission circuit having an AND circuit 40), and when one of the two request / response signal transmitting / receiving means transmits the request signal, the other of the two request / response signal transmitting / receiving means also receives the request signal. To send and receive two request / response signal transmitting / receiving means and 2
Since the two signal skew correcting means perform the same series of operations in both directions at the same time, the test signal is transmitted through the transmission line in one direction.
The signal-to-signal skew for bidirectional signal transmission can be corrected by the round-trip time, and the signal-to-signal skew can be corrected without impairing the original signal transmission efficiency.

[0047]

As described above, according to the first aspect of the present invention, in the parallel signal transmission device for transmitting a plurality of signals in parallel through the transmission path, the test signal is generated on the signal transmission side and the test signal is generated. Test signal transmitting means for transmitting a test signal to all the lines of the transmission line at the same timing, and all lines of the transmission line from the time when the test signal is received for each line of the transmission line on the signal receiving side. To measure and store the time from the reception of the test signal to the plurality of signals transmitted by each line of the transmission path, and delaying each of the plurality of signals by the stored time. Since the inter-signal skew correction means for correcting inter-signal skew generated during signal transmission is provided, the present invention can be applied even when the signal transmission direction of the transmission path is only one direction.

According to the second aspect of the present invention, in the parallel signal transmission device for transmitting a plurality of signals in parallel via the transmission path, the test signal transmitting side transmits the test signal to the test signal receiving side. Send a request signal to notify the transmission of the test signal before transmitting, and then return the response signal to the test signal transmitting side after receiving the request signal at the test signal receiving side and preparing to receive the test signal. , Signal-to-signal skew correction signal transmitting / receiving means for transmitting the test signal to all lines of the transmission path at the same timing after confirming the reception of the response signal at the test signal transmitting side, and the test signal receiving side. Then, the time from when the test signal is received for each line of the transmission path to when the test signal is received from all the lines of the transmission path is measured and stored, and is transmitted by each line of the transmission path. To the multiple signals And a signal-to-signal skew correction means for correcting the signal-to-signal skew that occurs during transmission of the plurality of signals by delaying the stored time by the stored time. Malfunctions can be prevented by returning the response signal to the test signal transmission side after receiving the signal and preparing to receive the test signal.

According to the third aspect of the present invention, a plurality of signals are transmitted in parallel via a transmission line, and in a parallel signal transmission device in which the transmission line is half-duplex, it is provided on both sides of the transmission line. Send a request signal to the other side to notify it of the test signal transmission before sending the test signal, receive the request signal from the other side and send a response signal back to the other side, and send the response signal from the other side. Two request / response signal transmitting / receiving means for receiving and a response of the request / response signal transmitting / receiving means provided on both sides of the transmission line and provided on the same side of the transmission line among the two request / response signal transmitting / receiving means The test signal is transmitted to all the lines of the transmission line at the same timing by signal reception, and the test signal is received from all the lines of the transmission line from the time when the test signal is received for each line of the transmission line. Time to Then, the signal-to-signal skew generated during the transmission of the plurality of signals is delayed by delaying the plurality of signals transmitted by each line of the transmission path by the stored time. To correct 2
Since the two signal / skew correction means are provided and the order of operation of the two request / response signal transmission / reception means and the two signal skew correction means is determined in advance, the transmission line has a half-duplex configuration. It can also be applied in cases.

According to the invention described in claim 4, in a parallel signal transmission device for transmitting a plurality of signals in parallel through a transmission line, and the transmission line is a full duplex, the parallel signal transmission device is provided on both sides of the transmission line. Send a request signal to the other side to notify it of the test signal transmission before sending the test signal, receive the request signal from the other side and send a response signal back to the other side, and send the response signal from the other side. Two request / response signal transmitting / receiving means for receiving and a response of the request / response signal transmitting / receiving means provided on both sides of the transmission line and provided on the same side of the transmission line among the two request / response signal transmitting / receiving means The test signal is transmitted to all the lines of the transmission line at the same timing by signal reception, and the test signal is received from all the lines of the transmission line from the time when the test signal is received for each line of the transmission line. Time to Then, the signal-to-signal skew generated during the transmission of the plurality of signals is delayed by delaying the plurality of signals transmitted by each line of the transmission path by the stored time. To correct 2
And one of the two request / response signal transmitting / receiving means transmits the request signal, and the other of the two request / response signal transmitting / receiving means transmits the request signal. Since the two request / response signal transmitting / receiving means and the two signal skew correcting means simultaneously perform the same series of operations in both directions, bidirectional signal transmission in a time period in which the test signal makes one round trip in the transmission path. The signal-to-signal skew can be corrected, and the signal-to-signal skew can be corrected without impairing the original signal transmission efficiency.

According to the invention of claim 5, claim 1,
In the parallel signal transmission device according to 2, 3, or 4, since the means performs a series of operations at least when the power is turned on,
The signal-to-signal skew can be reliably corrected without the need for the user to move, and highly reliable signal transmission can be realized.

According to the invention described in claim 6,
In the parallel signal transmission device according to 2, 3, 4 or 5,
Since the means repeats a series of operations every predetermined time, it is possible to suppress the occurrence of the signal-to-signal skew even if the signal-to-signal skew changes over time due to changes in the environmental temperature and the power supply voltage, and it is possible to improve the environment resistance. Excellent signal transmission can be realized.

According to the invention of claim 7, claim 2,
In the parallel signal transmission device according to 3, 4, 5 or 6,
Since the signal-to-signal skew correction signal transmission / reception means or the request / response signal transmission / reception means starts transmission of the request signal and the response signal after confirming that the transmission path is in an empty state, even if the signal-to-signal skew correction operation is performed, When there is some signal transmission at the start time, it is possible to wait until it is completely finished, and the signal-to-signal skew can be corrected correctly without impairing the original signal transmission efficiency.

According to the invention of claim 8, claim 2
In the parallel signal transmission device according to 3, 4, 5, 6 or 7, the signal transmission / reception means for signal skew correction or the request / response signal transmission / reception means cuts off a test signal from the transmission path when the request signal is received. Since it is not transmitted to the outside, it is possible to prevent the test signal from causing any trouble in the system, and it is possible to ensure the reliability of the system.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of a transmission device in an example of a system configuration using the transmission device according to an embodiment of the present invention as defined in claims 1, 2, 5-8.

FIG. 2 is a block diagram showing an outline of the system.

FIG. 3 is a block diagram showing a configuration example of a control circuit in a transmission device on the side of transmitting a test signal in the system.

FIG. 4 is a block diagram showing a configuration example of a control circuit in a transmission device on the side receiving a test signal in the system.

FIG. 5 is a block diagram showing an example of a signal transmission circuit in a transmission device on the side of transmitting a test signal in the system.

FIG. 6 is a block diagram showing an example of a signal transmission circuit in a transmission device on the side that receives a test signal in the system.

FIG. 7 is a block diagram showing a configuration example of a skew correction circuit in the signal transmission circuit.

FIG. 8 is a block diagram showing a control circuit in an example of a system configuration using the transmission device according to the third embodiment of the invention.

[Explanation of symbols]

11,12 transmission device 13 transmission path 13 ₁ to 13 _n lines 14, 15 the terminal device 16 the control circuit 17 ₁ to 17 _n signal transmission circuit 18 resistor 19 capacitor 20 buffer 21 timer 22,26,27,33～35,40 and Circuit 23, 32, 36, 39, 46 Inverter 24 Rising transition detection circuit 25, 30 Transmission line idle detection circuit 28 Test signal generation circuit 29 End detection circuit 31 Delay setting end detection circuit 37 OR circuit 38 Skew correction circuit 41 Reset circuit 42 Counter 43 Shift Register 44 Decoder 45 Multiplexer

Claims (8)

[Claims] 1. A parallel signal transmission device for transmitting a plurality of signals in parallel via a transmission line, wherein a test signal is generated at a signal transmission side and the test signal is transmitted to all lines of the transmission line at the same timing. The test signal transmitting means for transmitting, and measuring the time from the time the test signal is received for each line of the transmission line at the signal receiving side to the reception of the test signal from all the lines of the transmission line. A signal for storing and correcting the signal-to-signal skew that has occurred during the transmission of the plurality of signals by delaying the plurality of signals transmitted by each line of the transmission path by the stored time. A parallel signal transmission device comprising inter-skew correction means. 2. A parallel signal transmission apparatus for transmitting a plurality of signals in parallel via a transmission line, wherein a test signal transmitting side transmits a test signal before transmitting a test signal to a test signal receiving side. The test signal receiving side, the test signal receiving side receives the request signal and prepares to receive the test signal, and then returns a response signal to the test signal transmitting side. Signal transmission / reception means for inter-signal skew correction for transmitting the test signal to all the lines of the transmission line at the same timing after confirming the reception of the response signal, and for each line of the transmission line at the receiving side of the test signal The time from the time of receiving the test signal to the time of receiving the test signal from all the lines of the transmission line is measured and stored, and for the plurality of signals transmitted by each line of the transmission line. When each of the above is remembered By multiplying the amount corresponding delay, parallel signal transmission apparatus characterized by comprising a signal skew correcting means for correcting the signal skew occurring during the transmission of the plurality of signals. 3. A parallel signal transmission device for transmitting a plurality of signals in parallel via a transmission line, wherein the transmission line is half-duplex, provided on both sides of the transmission line, and a test signal is transmitted to the other side. Two request / response signals that send a request signal to notify the transmission of the test signal before sending the request, receive the request signal from the other party, send back the response signal to the other party, and receive the response signal from the other party The test signal is transmitted by receiving a response signal from the transmission / reception means and the request / response signal transmission / reception means provided on the same side of the transmission path among the two request / response signal transmission / reception means provided on both sides of the transmission path. All the lines of the transmission path are transmitted at the same timing, and the time from the reception of the test signal for each line of the transmission path to the reception of the test signal from all the lines of the transmission path is measured and stored. Each of the transmission lines Two inter-signal skew correction means for correcting inter-signal skew generated during transmission of the plurality of signals by delaying each of the plurality of signals transmitted through the line by the stored time. A parallel signal transmission device comprising: the two request / response signal transmission / reception means and the two signal skew correction means. 4. A parallel signal transmission apparatus for transmitting a plurality of signals in parallel through a transmission line, wherein the transmission line is a full-duplex parallel signal transmission device. Two request / response signals that send a request signal to notify the transmission of the test signal before sending the request, receive the request signal from the other party, send back the response signal to the other party, and receive the response signal from the other party The test signal is transmitted by receiving a response signal from the transmission / reception means and the request / response signal transmission / reception means provided on the same side of the transmission path among the two request / response signal transmission / reception means provided on both sides of the transmission path. All the lines of the transmission path are transmitted at the same timing, and the time from the reception of the test signal for each line of the transmission path to the reception of the test signal from all the lines of the transmission path is measured and stored. Each of the transmission lines Two inter-signal skew correction means for correcting inter-signal skew generated during transmission of the plurality of signals by delaying each of the plurality of signals transmitted through the line by the stored time. And when one of the two request / response signal transmitting / receiving means transmits the request signal, the other of the two request / response signal transmitting / receiving means also transmits the request signal to transmit / receive the two request / response signal transmission / reception signals. A parallel signal transmission device, wherein the means and the skew correction means between the two signals simultaneously perform the same series of operations in both directions. 5. The parallel signal transmission device according to claim 1, 2, 3 or 4, wherein the means performs a series of operations at least when the power is turned on. 6. The parallel signal transmission device according to claim 1, 2, 3, 4 or 5, wherein said means repeats a series of operations at predetermined time intervals. 7. The parallel signal transmission device according to claim 2, 3, 4, 5, or 6, wherein the transmission line of said signal skew correction signal transmission / reception means or said request / response signal transmission / reception means is in an idle state. A parallel signal transmission device, characterized in that the transmission of a request signal and a response signal is started. 8. A parallel signal transmission apparatus according to claim 2, 3, 4, 5, 6 or 7, wherein said signal skew correction signal transmitting / receiving means or said request / response signal transmitting / receiving means receives said request signal. A parallel signal transmission device, characterized in that a test signal from the transmission line is blocked so as not to be transmitted to the outside.