JPH01288128A - Two-way data transfer control method - Google Patents

Abstract

PURPOSE:To attain sure data transfer at high speed regardless of a delay time between a master and a slave equipment by preparing two strobe signals for synchronization and returning the strobe signal from the master equipment after the adjustment of the timing. CONSTITUTION:A strobe generator 2 generates a prescribed strobe signal and sends the signal to a slave equipment as the 1st strobe signal and to a synchronizing signal selection circuit 3. The slave equipment uses the 1st strobe signal as a synchronizing signal (clock) to receive (output) a data by a register 6. In this case, the 1st strobe signal is subject to timing adjustment and waveform shaping by a timing adjustment means 8 and is returned to the master equipment as the 2nd strobe signal. A register 4 receives the data by using the 2nd strobe signal as the synchronizing signal. Thus, the data is transmitted in a sure timing regardless of the delay time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a data transfer control method, particularly to a control method for performing bidirectional data transfer between a master device and a slave device.

Conventional technology In general, when data is transferred between two devices A (master device) and B (slave device), there are two methods: an asynchronous confirmation method in which each device confirms the other's operation and then transfers data, and a method in which one device is the master device and the other is the slave device. There is a synchronous non-confirmation method in which transfer is performed in synchronization with the above. In the former case, each party proceeds with the operation while checking the other party's operation, so reliable transfer is possible. An example of this method is an ACK return method using two control lines, a strobe signal and an ACK signal.

Problems to be Solved by the Invention However, the conventional asynchronous confirmation method for ACK return requires a processing circuit on the slave device side to receive data in accordance with a strobe signal and then return an ACK signal. Processing time is required. Therefore, the data transfer speed cannot be increased much.

In addition, with the synchronization non-confirmation method, there is no problem when transmitting data from the master device to the slave device because the strobe signal can be sent at a predetermined timing, but conversely, when the master device receives data, Due to processing time inside the slave device and signal propagation delay on the transmission path,
There may be cases where data does not return to the master device within a cycle.

In view of these problems, the present invention enables high-speed data transfer with a simple circuit configuration, regardless of signal delay time on the transmission path, when performing bidirectional data transfer between a master device and a slave device. The purpose is to provide a control method that is easy to use.

Means for Solving the Problems The present invention provides a system for bidirectional data transfer between a master device and a slave device, which includes two strobe signals between the master device and the slave device, and which transmits data from the master device. When transmitting data, the data is transmitted at a predetermined timing synchronized with the first strobe signal transmitted from the master device to the slave device, and conversely, when the master device receives data, the first strobe signal is transmitted from the master device to the slave device. The master device transmits data in response to the signal, and performs timing adjustment and waveform shaping on the first strobe signal by a timing adjustment means, or receives the data in synchronization with the second strobe signal that is returned as is. This is a bidirectional data transfer control method characterized by:

Operation: When transmitting data from the master device to the slave device, the first strobe signal is transmitted at a predetermined timing according to the transmitted data. The slave device takes in data using this first strobe signal as a synchronization signal. Also, when the master device receives data from the slave device, the master device transmits the first strobe signal.

The slave device transmits data to the master device using the received first strobe signal as a clock.

At this time, the first strobe signal is subjected to timing adjustment and waveform shaping by the timing adjustment means, and then sent back to the master device as a second strobe signal through a transmission path different from that of the first strobe signal. The master device takes in data from the slave device using this second strobe signal as a synchronization signal.

With the above configuration, when the master device receives data from the slave device, it can always receive the data and the second strobe signal at the predetermined timing, so it can be reliably received regardless of the delay time in the transmission path. Moreover, it becomes possible to transfer data at high speed.

Embodiment An embodiment of the bidirectional data transfer control method of the present invention is shown in FIG. The timing generation circuit 1 sends the strobe generation notification signal to the strobe generator 2 to the transmission/reception selection circuit 5.
The send/receive selection notification signal is notified to each of the send/receive selection notification signals. The strobe generator 2 generates a predetermined strobe signal and transmits it to the slave device as a first strobe signal, and also transmits it to the synchronization signal selection circuit 3. When transmitting data from the master device to the slave device, the strobe generator 2
The signal sent from the register 4 is sent to the register 4. register 4
outputs data to the slave device using this signal as a clock. In the slave device, data is received by the register 6 using the first strobe signal as a synchronization signal. Here, the strobe signal is sent to the register 6 and, as shown in the figure, is sent back to the master device as a second strobe signal through the timing adjustment means 8. FIG. 2(a) shows a time chart during data transmission.

On the other hand, when the master device receives data from the slave device, the slave device outputs data from the register 6 using the first strobe signal as a clock in response to a notification signal from the transmission/reception selection circuit 7. At this time, as in the case of transmission, the first strobe signal is subjected to timing adjustment and waveform shaping by the timing adjustment means 8, and is then sent back to the master device as a second strobe signal. The timing adjustment means 8 uses a buffer, an inverter, a delay circuit, etc. depending on the access time from strobe input to data output in the slave device.

The synchronization signal selection circuit 3 of the master device sends the second strobe signal returned from the slave device to the register 4 in accordance with the notification from the transmission/reception selection circuit 5. register 4
Then, data is received using this signal as a synchronization signal. Second
Figure (b) shows a time chart during data reception. As shown in the figure, since the contribution of the delay time t in the transmission path to the data and the strobe signal is the same, as long as the timing is adjusted appropriately by the timing adjustment means 8, regardless of the value of the delay time, reliable Data can be transferred in a timely manner.

The timing adjustment means 8 may be provided inside the slave device as shown in FIG.
It is also possible to provide it using a delay line or the like.

Effects of the Invention The bidirectional data transfer control method according to the present invention has two strobe signals for synchronization, and returns the strobe signal from the master device after timing adjustment, so that the data from the slave device and the strobe signal can be A predetermined timing can be obtained. Therefore, reliable bidirectional data transfer can be performed regardless of the signal delay time on the transmission line between the master device and the slave device. Further, since a complicated processing circuit is not required for returning the strobe, data can be transferred at high speed.

As described above, the bidirectional data transfer control method according to the present invention can perform high-speed and reliable data transfer with a simple circuit configuration regardless of the delay time between the master and slave. Therefore, it is extremely effective for various information processing devices, especially for network data transfer of parallel computers having a large number of data transmission paths.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for an embodiment of the present invention;
FIG. 2 is a time chart diagram of the same block configuration example. 1... Timing generation circuit, 2... Strobe generator, 3... Synchronization signal selection circuit, 4
...Register, 5...Transmission/reception selection circuit, 6...Register, 7...Transmission/reception selection circuit, 8... Timing adjustment means.

Claims (1)

[Claims] In a system that performs bidirectional data transfer between a master device and a slave device, two strobe signals are provided between the master device and the slave device. Data is transmitted at a predetermined timing synchronized with a first strobe signal transmitted to the device, and conversely, when the master device receives data, the slave device transmits data in response to the first strobe signal. and the master device receives the data in synchronization with the second strobe signal which is subjected to timing adjustment and waveform shaping on the first strobe signal by a timing adjustment means or is returned as is. Control method.