JPH0221737A - Data source - Google Patents

Abstract

PURPOSE:To send a data with less terminal number by providing a 2nd reset generator receiving an output signal of a 1st reset generator and a switch receiving the 1st and 2nd data and switching the 1st and 2nd data by an output signal from the 2nd reset generator. CONSTITUTION:The switch 5 receiving the 1st and 2nd data and switching the 1st and 2nd data by an output signal from the 2nd reset generator is provided. A time difference is provided between a time from an output signal of the 1st reset generator 1 going to a high level and till the release of the reset of a data source and a time from an output signal of the 2nd reset generator 2 going to a high level and till the release of the reset signal outputted from the 2nd output terminal 7 at application of power. The 1st data is sent during that time, after a reset signal outputted from the 2nd output terminal 7 is released, the 2nd data is sent. Thus, the multiplex of the data transmission is applied without providing a switching signal input terminal for data changeover.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention transmits first data at power-on initialization, and after initialization, transmits second data using the same line as the first data. The present invention relates to a data transmitter with a reduced number of terminals.

2. Description of the Related Art In data transfer between ICs or circuit blocks, a method of switching and outputting a plurality of data to a transfer line has been used in the past.

An example of the conventional data transmission described above will be described below with reference to the drawings.

FIG. 3 shows a block diagram of a conventional data transmitter. In FIG. 3, 8 is a reset generator, 9 is a first input terminal for inputting first data, IO is a second input terminal for inputting second data, and 11 is a third input terminal for inputting a switching signal. Input terminal, 12 is a switch that switches between the first data and the second data with a switching signal, and 13 is a switch I2
The first output terminal 14 outputs the output signal of the reset generator 8, and the second output terminal 14 outputs the output signal of the reset generator 8.

The operation of the data transmitter configured as described above will be explained below.

First, when the power is turned on, the reset generator 8 keeps its output at a low level for a certain period of time, and then raises it to a high level.

switch! 2 selects the first data based on a switching signal inputted from the third input terminal II, and the first data is outputted to the first output terminal 13. When the switching signal is inverted, the switch 12 selects the second data,
Second data is output to the first output terminal 13.

Problems to be Solved by the Invention However, in the above configuration, since a switching signal is used to switch between the first and second data, it is necessary to provide an input terminal for inputting the switching signal.

In view of the above problems, the present invention provides a data transmitter that can multiplex data transmission without providing a switching signal input terminal for data switching.

Means for Solving the Problems In order to solve the above problems, the data transmitter of the present invention includes a first reset generator, a second reset generator which receives the output signal of the first reset generator. , input the first input data and the input second data, and input the second input data.
The output signal of the glue set generator is used to generate the first data and the second data.
The device is equipped with a switch for switching and outputting the data.

Operation The present invention has the above-described configuration, and when the power is turned on and the first
The output signal of the second reset generator becomes high level and the reset signal of the data transmitter is released, and the output signal of the second reset generator becomes high level and the reset signal output from the second output terminal is released. After the first data is overwritten and the reset signal output from the second output terminal is released,
By transmitting the second data, an input terminal for switching the second data can be omitted.

Embodiment Hereinafter, a data transmitter according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a block diagram of a data transmitter in an embodiment of the present invention. In FIG. 1, 1 is a first reset generator, 2 is a second reset generator that outputs a high level signal after a predetermined time after the output of the first reset generator 1 becomes high level, and 3 is a second reset generator that outputs a high level signal after a predetermined time. 4 is the first input terminal for inputting the first data, 4 is the second input terminal for inputting the second data, 5 is the second input terminal
A switch that outputs the first data or the second data based on the output of the reset generator 2, 6 is an output terminal for outputting the selected data, and 7 is a second output terminal for reset output. It is an output terminal.

The operation of the data transmitter configured as described above will be described below with reference to FIGS. 1 and 2. FIG. 2 is a timing diagram of the operation of the embodiment of FIG.

When the power is first turned on, the first reset generator 1 keeps its output at a low level for a certain period of time (tl) and then raises it to a high level. The output signal of the second reset generator 2 becomes a low level when the power is input, and when the output signal of the first reset generator 1 becomes a high level, the output is kept at a low level for a certain period of time (t2). Then it becomes high level. The switch 5 selects the first data if the output signal of the second reset generator 2 is at a low level, and selects the second data if the output signal is at a high level. Therefore, after the t+ source is input to the first output terminal 6, the second
The first data is output until the output of the reset generator rises from low level to high level, and after that, the second data is output. Note that the second reset generator 2 may be configured with a delay element or a delay circuit having a delay time (t2).

Effects of the Invention As described above, the present invention includes a first reset generator and a first reset generator.
a second reset generator which receives as input the output signal of the reset generator;
and a switch for switching between the first data and the second data using the output signal of the second reset generator. The first and second data can be switched and output without providing a terminal, and data can be transmitted with a small number of terminals.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a data transmitter according to an embodiment of the present invention, FIG. 2 is a timing diagram showing the operation of the data transmitter of FIG. 1, and FIG. 3 is a block diagram of a conventional data transmitter. . 1......First reset generator, 2...
...Second reset generator, 3...
...First input terminal, 4...Second input terminal, 5...Switch, 6...
. . . first output terminal, 7 . . . second output terminal.

Claims (1)

[Claims] a first reset generator, a second reset generator that receives the output signal of the first reset generator, inputs the input first data and the input second data;
A data transmitter comprising a switch that outputs the first data and the second data by switching between the first data and the second data using the output signal of the second reset generator.