[background technology]
The world today, the electronic technology develop rapidly, the electronic product of various functions has entered huge numbers of families, has improved people's living standard.But these electronic product functions are single relatively, if will realize multiple function, each electronic product need be coupled together, and the connection complexity between each electronic product, complex operation uses very inconvenient.Electronic product with multiple function is integrated into a new product with a plurality of electronic products originally, and is simple to operate because it has, with low cost, the outward appearance grace, advantages such as it is little to take up room become user's new lover, also become an important directions of industry product development
In the process that these products are integrated, circuit module co-ordination mutually with various functions, operation such as sending controling instruction, transmission operating state each other, these operations must take input/output port (the In/Out port of each module, be called for short the I/O port), former the design with regard to compact condition under, do not have the space to increase new I/O port, at this moment the original I/O port of some module will become not enough.As shown in Figure 1, be with originally independently A module and B module combinations, the A module will intercom mutually with the B module, just must take the A1 of A module, the B1 of A2 and B module, each two I/O mouth of B2, the A module does not just have abundant port to be connected with other functional module like this.Therefore after combination A, B module, the not enough situation of I/O port may appear in the A module.
Therefore, be necessary to propose a kind of new technical scheme and solve foregoing problems.
[summary of the invention]
The object of the present invention is to provide a kind of communication means, it can realize only carrying out the two-way signaling transmission by an input-output line.
For reaching above-mentioned purpose, a kind of single-wire pseudo two-way communication of the present invention, this method is used for communicating in first module and second intermodule, wherein first module has first input/output port, second module has first input/output port and second input/output port, it is characterized in that: series resistance forms bleeder circuit between second input/output port of the power supply and second module, first input/output port of first module and second module is connected in this bleeder circuit, the first signal input output end mouth of first module is changeable to be two kinds of different states of input and output, and signal is transferred to first input/output port transmission of second module from first input/output port of first module under first state; Under second state, signal is transferred to first input/output port transmission of first module from second input/output port of second module.
Compared with prior art the present invention has following beneficial effect: the present invention is by being provided with circuit between two handshaking modules, be in two kinds of different states by the input/output port of controlling a module, and the different transmission direction of realization signal under two states, reach the requirement that only just can realize the transmitted in both directions signal, under the condition of limited of module space, can save the input/output port of module with an input/output port of one of them module.
[embodiment]
See also shown in Figure 2ly, present embodiment is a kind of LCD TV with ground digital signal reception.It is to increase a DVB (Digital VideoBroadcasting on the basis of original television set (TV) solution, digital video broadcasting) digital received plate, from TV module 1 output order to DVB module 2, the OSD of DVB module 2 (On-Screen Display, screen display) state feedback is given TV module 1.
TV module 1 comprises the first input/output port A1 and the second input/output port A2, and DVB module 2 comprises the first input/output port B1 and the second input/output port B2.Between the second input/output port B2 of power supply VCC and DVB module 2, be in series with two resistance R 1, R2.The first input/output port A1, the B1 of TV module 1 and DVB module 2 is connected in and forms node J between aforementioned two resistance R 1, the R2.
When the user operates, TV module 1 at first needs to detect the OSD state of DVB module 2, signal demand passes to port A1 from port B2, change the high-low level of DVB module 2 software control port B2 output this moment, this moment, port A1 switched to buck stages OD door input state, the level height that node J is ordered is controlled by port B2 fully, thereby can finish the transmission from port B2 to port A1.
When TV module 1 was given an order, signal demand was by the port B1 of the port A1 input DVB module 2 of TV module 1.Switch to the first input/output port A1 of TV module 1 and recommend output state this moment, the first input/output port A1 output current of TV module 1 is enough big under this kind state, no matter how the second input/output port B2 of DVB module 2 level of ordering changes, the first input/output port A1 of TV module 1 can control the level height that node J is ordered fully, and the first input/output port B1 point of DVB module 2 then receives the signal that transmits from port A1.
Behind port A1 end of transmission, port A1 is switched to OD door input state by output state, be used to receive the signal that transmits from port B2, thus when the input/output port A1 of TV module 1 is in two kinds of different conditions, signal all can folk prescription to transmission.
The transmission direction of signal is to be controlled by the main control module of entire product, and main control module is a TV module 1 in the present embodiment, and main control module can be controlled the time and the direction of TV module 1 and 2 signal transmission of DVB module.
The signal of transmission from port A1 to port B1 with from port B2 to port A1, its content and coding can design voluntarily, can transmit data by rising or the trailing edge that detects level, also can transmit data by the pulsewidth that changes high-low level, can also utilize some coding rules commonly used to realize transfer of data, for example remote control mode transmission etc.
When signal was transferred to port A1 by port B2, this moment, port B1 also received this signal, therefore can design port B2 and be transferred to the port B1 that is coded in of port A1 to receive backsight be invalid, and this problem can solve by software.
The resistance of R1 is 10K Ω in the present embodiment, the resistance of R2 is 1K Ω, the selection of resistance R 1 and resistance R 2 resistances in other embodiments is a principle to satisfy following requirements: when signal by port A1 input port B 1 time, port A1 recommends output current much larger than the dividing potential drop electric current; When signal during by port B2 input port A1, the change in voltage that node J is ordered during port B2 control output meets the height threshold voltage of port A1.In the signal transmission, port A1, the B1 of two modules, B2 high-low level require and can match each other in addition, can not cause damage and thresholding not to match.
Communication means principle of the present invention is simple, easy to implement, increases with low costly, can save an input/output port B2 of TV module, is convenient to the mutual combination of intermodule.