JPH01149154A - Data transfer system - Google Patents

Abstract

PURPOSE:To transfer data at high speed irrespective of the difference of a propagation skew by measuring the quantity of delay for every line by a test signal and automatically correcting the propagation skew according to this measured result. CONSTITUTION:A path for passing the test signal transmitted via one of the lines of parallel input and output interfaces 3 from a host device 1 through all turning back means 4 is set. Then, the delay time of the test signal generated in this path is measured by a skew measuring means 7 and the quantity of the delay of a skew correcting means 5 inserted into a receiving line in the host device 1 is adjusted in a skew adjusting means 8. Then, the test signal is transmitted via the turning back means 4 for every one pair of lines from the host device 1 and based on the delay tie of this test signal, the quantity of the delay of the skew correcting means 5 inserted into the transmitting line is adjusted by the skew adjusting means 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is applied to a data transfer system. In particular, the present invention relates to skew compensation means for correcting propagation skew between signals occurring in a parallel interface.

〔overview〕

The present invention is a means for correcting propagation skew between signals that occurs in parallel interfaces, which measures the amount of delay for each line using a test signal and automatically corrects the propagation skew based on the measurement results, regardless of differences in propagation skew. This allows data to be transferred at high speed.

[Conventional technology]

Conventionally, when transmitting and receiving information on a parallel input/output interface, the skew in signal propagation between interface signals increases in proportion to the length of the interface cable, so even if the transmitting side sends out signals at the same time, it is difficult to receive them. On the other hand, variations occur before the signal is determined due to cables, signal driving, and propagation delays in the receiving circuit. therefore,
In order to reliably send and receive information, this propagation skew must be taken into account and information is sent and received only after the signal is determined.

[Problem that the invention seeks to solve]

However, when transmitting and receiving information over such conventional parallel input/output interfaces, the longer the cable length, the longer it takes for the receiving side to determine the information, which limits the data transfer speed or slows down the required data transfer. A drawback is that a limit must be placed on cable length to achieve speed.

The present invention aims to eliminate these drawbacks, and aims to provide a data transfer method that can transfer data at high speed regardless of cable length.

[Means for solving problems]

In the present invention, one of the opposing devices is provided with a skew correction means that is provided corresponding to the line and delays the signal passing through the device, and the other of the opposing devices is provided with a skew correction means that delays the signal passing through the device. Further, one of the above-mentioned devices includes a return operation control means for setting a route for a test signal sent from the own device and returned to the own device via the return means, and skew measuring means for measuring the time taken by the test signal to pass through the route set by the control means; and skew adjusting means for adjusting the amount of delay given by the skew correcting means based on the time measured by the skew measuring means. It is characterized by having

[Effect]

First, a route is set in which the test signal sent from the own device via one of the lines passes through all loopback means, the delay time of the test signal occurring on this route is measured, and the test signal is inserted into the receiving line within the own device. The amount of delay of the skew correction means is adjusted.

Next, a test signal is sent out from the own device via the return means for each - pair of transmission and reception lines, and the delay amount of the skew correction means inserted in the transmission line is adjusted based on the delay time of this test signal.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block configuration diagram showing the configuration of an embodiment of the present invention.

As shown in FIG. 1, this embodiment includes a higher-level device 1, a lower-level device 2, and a parallel input/output interface 3 between the higher-level device 1 and the lower-level device 2, where the lower-level device 2 includes: The host device 1 includes a folding means 4 that cuts the transmitted signal from the original mode signal to a folded signal based on an instruction from the host device 1, and the host device 1 includes a skew correction means 5 consisting of a delay line that corrects the propagation skew of the interface signal. , a skew measurement comprising a microprogram-based loopback operation control means 6 that instructs switching from the original mode to the loopback test mode and controls skew adjustment by the loopback operation, and an up/down counter that measures the skew of the received signal due to the loopback operation. and a skew adjusting means 8 for adjusting the correction value of the skew correcting means 5 based on the skew value of the skew measuring means 7. That is, in this embodiment, the upper device 1 and the lower device 2, which are opposing devices,
The host device 1 is equipped with a parallel input/output interface 3, which is an ink interface including a plurality of lines through which each of the signals sent and received between the devices independently passes, and the host device 1 is provided corresponding to the lines, and the signals passing through its own means. The lower device 2 is equipped with a return means 4 through which the test signal passes, and the upper device 1 is provided with a skew correction means 5 for giving a delay to the test signal. a loopback operation control means 6 for setting a route for the test signal to be looped back to the loopback operation control means 6; a skew measurement means 7 for measuring the time taken for the test signal to pass through the route set by the loopback operation control means 6; and skew adjustment means 8 for adjusting the amount of delay given by the skew correction means 5 based on the time measured by the skew correction means 5.

FIG. 2 shows a return operation for adjusting the skew of signals in the manual direction from the lower device 2 to the higher device 1, and FIG. 3 shows the skew adjustment of signals in the output direction from the higher device 1 to the lower device 2. It is an explanatory view showing a return operation. The switching circuits 4-1 and 4-2 are included in the return means 4, and the delay line 5-
Reference numeral 1 denotes a delay line included in the skew correction means 5 for adjusting the skew of the human-powered direction signal, and the delay line 5-
2 is a delay line included in the skew correction means 5 for skew 1 of the output direction signal. First, as shown in FIG. 2, a loopback operation is executed by microprogram control using the same signal as a loopback signal source, and the skew between each manual direction interface signal is measured by the skew measuring means 7 consisting of an up/down counter. , the delay line 5-1 is adjusted to correct the skew between the human input direction signals. Next, as shown in FIG. 3, a similar skew measurement is performed by folding back each output direction interface signal, and the delay line 5-2 is adjusted to correct the skew between the output direction signals. Here, delay adjustment is performed on the diagonally shaded delay line in the figure.

〔Effect of the invention〕

As explained above, the present invention is capable of automatically correcting the propagation skew of interface signals caused by the transmission and reception of information on a parallel interface using a microprogram, so that data can be transferred at high speed regardless of the cable length. There is an effect that can be done.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram showing the configuration of an embodiment of the present invention. FIGS. 2 and 3 are explanatory diagrams showing the folding operation of the embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Upper device, 2... Lower device, 3... Parallel human output interface, 4... Return means, 4-1.4-
2... Switching circuit, 5... Skew correction means, 5-1
．． 5-2... Delay line, 6... Return operation control means, 7... Skew measuring means, 8... Skew adjustment means, 9.10... Output direction interface before and after skew correction Signal, 11.12... Human power direction interface signal before and after skew correction,
Dl. Drive circuit, R...reception circuit.

Claims (1)

[Claims] (1) In a data transfer system equipped with an interface including a plurality of lines through which each signal sent and received between opposing devices passes independently, one of the opposing devices is provided with a link corresponding to the line, A skew correction means (5) for delaying a signal passing through the own means is provided, the other of the opposing devices is provided with a folding means (4) through which a test signal passes, and the one device is provided with: loopback operation control means (6) for setting a route for a test signal sent from the own device and looped back to the own device via the loopback means, and a test signal passing through the route set by the loopback operation control means. and skew adjustment means (8) for adjusting the amount of delay given by the skew correction means based on the time measured by the skew measurement means. data transfer method.