JPS63287234A - Data format - Google Patents

Abstract

PURPOSE:To prevent data fetch mistake surely by using a format arranged sequentially with a start byte, a data and a non-signal part on a time axis as one transmission unit. CONSTITUTION:The data format of one transmission unit is formed by, for example, an 8-bit start byte area 1, a 56-bit data area 2, and a 64-bit non-signal area 3. In starting data fetch from a point of time B in figure, at first, the data inputted so far is aborted till the non-signal area 3 is detected, and in detecting the non-signal area 3, the end of it is awaited and the data of the data area 2 is fetched at a point of time when the start byte area 1 is detected. Thus, data fetch in an optional timing is implemented without any mistake in an asynchronizing system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data format suitable for an asynchronous system.

[Conventional technology]

In a system using multiple CPUs, the main CPU
When U performs asynchronous communication in which data is always transferred to the sub CPU, data is transferred in a data format as shown in FIG.

[Problem that the invention seeks to solve]

However, when transferring data in this format, if the sub CPU inputs data from point A of the data format, it will detect that the same format as the start byte exists in the input data, so it will only transfer data for one sending unit. This will result in input errors.

The object of the present invention is to provide a data format that is effective in preventing such data import errors.

[Means for solving problems]

For this reason, the present invention uses a format in which the start byte, data, and no-signal portion are sequentially arranged on the time axis as one transmission unit.

[Effect]

By setting the data format like this,
Using the end of detection of the no-signal portion as the key, it becomes possible to reliably detect the subsequent start bite.
Data import errors can be reliably prevented.

〔Example〕

Hereinafter, uninvented embodiments will be described. FIG. 1 is a diagram showing the data format of one embodiment. In this embodiment, an 8-bit start byte area, 1.56-bit data area 2, and a 64-bit no-signal area 3 provide the following:
The data format is set for one transmission unit. That is, a new no-signal portion is provided with the same number of bits as the number of bits required for start byte area 1 and data area 2.

FIG. 2 is a flowchart for importing data in the format shown in FIG. For example, B in Figure 1
If you start data acquisition from this point, first discard the data manually generated until no-signal area 3 is detected.
When no-signal area 3 is detected, it waits for it to end, and then when start byte area 1 is detected, it starts data area 2.
import data.

Figure 3 is a diagram showing the hardware configuration for this purpose.
Data area 2 transferred in the above data format
This is a case where the data is video data. In this case, the video data transferred from the main CPU 10 is processed in the sub CPU 12 by the processing program shown in FIG. The display data is taken in from the V-RAMI 4 and output as a video signal.

Using such a data format, e.g.
When displaying an analog clock on RT, it is possible to eliminate errors in displaying the hands.

〔Effect of the invention〕

As described above, according to the data format of the present invention, data and evening data can be captured at arbitrary timings without mistakes in an asynchronous system.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of a data format according to an embodiment of the present invention, Figure 2 is a flowchart of a program that imports data transferred in that data format, and Figure 3 is a diagram of the hardware that executes the program in Figure 2. FIG. 4, a diagram showing the configuration, is an explanatory diagram of a conventional data format. Agent Patent Attorney Tsune Akira Nagao Figure 1 tir■ D-sai signal ti+++e

Claims (2)

[Claims] (1) A data format in which a start byte, data, and no-signal portion are arranged sequentially on the time axis as one transmission unit. (2) The data format according to claim 1, wherein the same number of bits as the start byte and the total number of bits required for data transmission are assigned to the no-signal portion.