JPH035623B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data transmission/reception method, and an object thereof is to provide a method that does not require providing a strobe signal line for instructing data read timing separately from a data transmission line.

A conventional data transmission/reception method is shown in FIG. In this figure, the transmitting side (TX) and the receiving side (RX) are connected by a total of five signal lines, four transmission lines _l1 to _l4 and one strobe signal line _l5 . On the transmitting side (TX), each 4-bit digit series data D ₁ ,
D ₂ , D ₃ . . . are applied in bit parallel to the transmission lines l _{1 to l 4} as shown in FIG. Applied to signal line _l5 . On the receiving side (RX), each time the strobe signal P is generated on the strobe signal line (l ₅ ), the four transmission lines l ₁ to
It is configured to read the state of l ₄ as data. However, when microcomputer A is used as a processing device on the transmitting side (TX), microcomputer A is used to generate the strobe signal _P1 .
The current situation is that the burden on people is becoming heavier.

In the present invention, when N bits of data are sequentially transmitted over N transmission lines, each time one data transmission ends, the N bits of data are transmitted from the data transmission end time to the next data transmission start time on the transmitting side. All transmission lines are inverted to logic level "H", and on the receiving side,
When it is detected that all N transmission lines have been inverted to logic level "H", the state of the transmission lines after a predetermined time is read as the N bit data, making the conventional strobe signal and its transmission line unnecessary. A specific embodiment of the present invention will be described below with reference to FIGS. 3 and 4. In addition,
Here, an example will be explained in which data is transmitted from an electronic toll scale to a printer device.

1 is an electronic toll scale as a transmitting side, 2 is a printer device as a receiving side, and l ₁ to _{l 4} are four transmission lines connecting the electronic toll scale 1 and the printer device 2. The electronic toll scale 1 side has data such as tare, weight, price, unit price, etc. as data to be transmitted, and the microcomputer B on the electronic toll scale 1 side has a data sending routine configured as follows. There is.

In microcomputer B, the order of data to be transmitted is tare → weight → price → as shown in Figure 4 a.
It is determined that the cycle is repeated in the order of the unit price, and the time between the end time of one data transmission and the start of the next data transmission is F ₁₆ [If written in bits, the transmission line
It is configured such that all _l1 to _l4 are held at a logic level of "H" for transmission. Note that the data is transmitted in bits in parallel and in series, and each data transmission time _t1 is equal.
The time t ₂ of F ₁₆ is also equal.

Further, on the printer device 2 side that reads the above signals via transmission lines _l1 to _l4 , an AND gate 3 performs a logical product of the transmission lines _l1 to _l4 , and when this AND gate 3 detects a match, a timer 4 is activated. stipulated time through t ₃
[However, t ₃ > t ₂ ] After that, the pulse generator 5 is instructed to generate the interrupt pulse P ₂ . FIG. 4b shows this interrupt pulse _P2 , and it can be seen that the interrupt pulse _P2 is generated within the data transmission time _t1 . In addition, here, data transmission such as tare, weight, price, unit price, etc.
F ₁₆ is not used. The interrupt pulse _P2 acts as an interrupt signal on the microcomputer 6 of the printer device 2, where when the microcomputer 6 is interrupted by the interrupt pulse _P2 ,
It is configured to read the current state of the receiving end of the transmission lines _l1 to _l4 as information.

In addition, since (t ₁ + t ₂ ) is constant here, the microcomputer 6 is configured to check whether or not an interrupt is applied at approximately (t ₁ + t ₂ ) intervals, so that the transmission can be controlled. It is also possible to detect disconnection of the lines _l1 to _l4 .

As explained above, according to the present invention, there is no need to provide a strobe signal transmission line in addition to the N transmission lines as in the past, and accurate information can be read on the receiving side without creating a strobe signal. , the load on the microcomputer on the transmitting side can be reduced by that much, and the microcomputer can be effectively used for other purposes by this reduced amount. In addition, by checking the interval at which all N transmission lines are inverted to logic level "H" on the receiving side, the receiving side can check for disconnections in the N transmission lines, making it even more convenient. Accurate data transmission can be expected.

[Brief explanation of the drawing]

Fig. 1 is a connection diagram of the transmitting side and receiving side of a conventional data transmission/reception system, Fig. 2 is a waveform diagram of Fig. 1, Fig. 3 is a block diagram of a specific embodiment of the present invention, and Fig. 4 3A and 3B are diagrams showing the transmission format and main part waveforms inside the receiving side in FIG. 3; 1...Electronic toll scale [sending side], 2...printer device [receiving side], 3...and gate, 4...
...Timer, 5...Pulse generator, 6, B...Microcomputer, _l1 to _l4 ...Transmission line, _P2 ...Interrupt pulse.

Claims (1)

[Claims] 1. When transmitting N bits of data sequentially over N transmission lines, the transmitting side transmits data over the N transmission lines from the data transmission end time to the next data transmission start time every time one data transmission ends. When the reception side detects that all N transmission lines have been inverted to logic level "H", the state of the transmission lines after a predetermined time is used as the N-bit data. Data transmission/reception method to read.