CN201698195U

CN201698195U - Expansion circuit of single chip microcomputer IO ports

Info

Publication number: CN201698195U
Application number: CN2010202097831U
Authority: CN
Inventors: 赵新荣
Original assignee: NINGBO HAICHENG ELECTRIC AL APPLIANCES CO Ltd
Current assignee: Aux Air Conditioning Co Ltd
Priority date: 2010-05-28
Filing date: 2010-05-28
Publication date: 2011-01-05
Anticipated expiration: 2020-05-28

Abstract

The utility model discloses an expansion circuit of single chip microcomputer IO ports, which can solve the problem of shortage of the IC ports on the premise of lower cost and comprises a first-fifth resistors and a first triode and a second triode; one ends of the first resistor and the second resistor are respectively connected with the IO ports of the single chip microcomputer; the other end of the first resistor and one end of the third resistor are respectively connected with the base of the first triode; the emitter of the first triode and the other end of the third resistor are respectively connected with one end of the fifth resistor; one end of the fifth resistor is also connected with a working power supply of the single chip microcomputer; the collector of the first triode is used as a first signal output end; the other end of the second resistor and one end of the fourth resistor are respectively connected with the base of the second triode; the emitter of the second triode and the other end of the fourth resistor are respectively connected with a grounding end; the collector of the second triode is connected with the other end of the fifth resistor; and the collector of the second triode is used as a second signal output end.

Description

The expanded circuit of single-chip microcomputer IO mouth

Technical field

The utility model relates to the singlechip technology field, specifically is a kind of expanded circuit of single-chip microcomputer IO mouth.

Background technology

Present single-chip microcomputer, its IO mouth generally is connected with controlled device, because IO mouth number is fixed often, so work as controlled device more for a long time, will cause IO mouth problem of shortage, the method of head it off is changed the more single-chip microcomputer of IO mouth number often, though solved problem like this, cost increases greatly.

The utility model content

The technical problems to be solved in the utility model is that a kind of expanded circuit that can solve the single-chip microcomputer IO mouth of IO mouth shortage problem under lower-cost prerequisite is provided.

The technical solution of the utility model is, the expanded circuit of the utility model single-chip microcomputer IO mouth, it comprise first, second, third and fourth, five resistance and first and second triode, first and second triode is respectively positive-negative-positive triode and NPN type triode; One end of first and second resistance all is connected with the IO mouth of single-chip microcomputer, one end of the other end of first resistance and the 3rd resistance all is connected with the base stage of first triode, the other end of the emitter of first triode and the 3rd resistance all is connected with an end of the 5th resistance, one end of the 5th resistance also is connected with the working power of single-chip microcomputer, and the collector of first triode is as first signal output part; One end of the other end of second resistance and the 4th resistance all is connected with the base stage of second triode, the other end of the emitter of second triode and the 4th resistance all is connected with earth terminal, the collector of second triode is connected with the other end of the 5th resistance, and the collector of second triode is as the secondary signal output terminal; The single-chip microcomputer of described single-chip microcomputer for carrying out the appointment of I/O state separately to one of them IO mouth of single-chip microcomputer by its plug-in, and incoming level is the CMOS incoming level, output form is the CMOS three-state.

The resistance of first and second resistance equates, is 1K Ω; The resistance of third and fourth resistance equates, is 200 Ω; The resistance of the 5th resistance is 5.1K Ω; The input voltage of the working power of single-chip microcomputer is 5V.

After adopting said structure, the utility model compared with prior art has the following advantages:

Principle of work of the present utility model is, when the state of the IO of single-chip microcomputer mouth changes, promptly when the IO of single-chip microcomputer mouth output 0 or 1 or the IO of single-chip microcomputer when being changed to the input port, the voltage of the base stage point of the voltage of base stage point of first triode and second triode will be obtained, the voltage of the base stage point of first triode is compared with the voltage of the emitter of first triode, to determine the whether conducting of first triode, the first triode conducting, then the output of first signal output part 1, not conducting, first signal output part output 0; The voltage of the base stage point of second triode is compared with the voltage of the emitter of second triode, will determine the whether conducting of second triode, the second triode conducting, and then the output of secondary signal output terminal 0, not conducting, secondary signal output terminal output 1.

Briefly, the state of the IO mouth of single-chip microcomputer change determined first triode and second triode conducting whether, like this, the IO mouth of single-chip microcomputer just can obtain two signal output parts, thereby solve IO mouth problem of shortage by the utility model, and the component number that adopts is few, annexation is simple, and cost is low, so the utlity model has the advantage that can solve IO mouth shortage problem under lower-cost prerequisite.

Description of drawings

Accompanying drawing is the circuit theory diagrams of the expanded circuit of the utility model single-chip microcomputer IO mouth.

Embodiment

The utility model is described in further detail below in conjunction with accompanying drawing.

The expanded circuit of the utility model single-chip microcomputer IO mouth, it comprise first, second, third and fourth, five resistance (R1, R2, R3, R4, R5) and first and second triode (Q1, Q2), first and second triode is respectively positive-negative-positive triode and NPN type triode; One end of first and second resistance all is connected with the IO mouth (P1.0) of single-chip microcomputer, one end of the other end of first resistance and the 3rd resistance all is connected with the base stage of first triode, the other end of the emitter of first triode and the 3rd resistance all is connected with an end of the 5th resistance, one end of the 5th resistance also is connected with the working power of single-chip microcomputer, and the collector of first triode is as first signal output part (Uo1); One end of the other end of second resistance and the 4th resistance all is connected with the base stage of second triode, the other end of the emitter of second triode and the 4th resistance all is connected with earth terminal, the collector of second triode is connected with the other end of the 5th resistance, and the collector of second triode is as secondary signal output terminal (Uo2); The single-chip microcomputer of described single-chip microcomputer for carrying out the appointment of I/O state separately to one of them IO mouth of single-chip microcomputer by its plug-in, and incoming level is the CMOS incoming level, output form is the CMOS three-state.The expanded circuit of the utility model single-chip microcomputer IO mouth is used to expand the single-chip microcomputer with These characteristics, and this class single-chip microcomputer is commercially available commonly used.

In this example, the resistance of first and second resistance equates, is 1K Ω; The resistance of third and fourth resistance equates, is 200 Ω; The resistance of the 5th resistance is 5.1K Ω; The input voltage of the working power of single-chip microcomputer is 5V.

In digital circuit, noble potential is commonly defined as 1, and electronegative potential is commonly defined as 0, also is like this in this example.

When single-chip microcomputer P1.0 is output as 0, the voltage that Ub1 is ordered is (1000/1200) * 5V=4.16V, Q1 transistor emitter voltage is 5V, and the emitter of positive-negative-positive triode Q1 and base stage pressure reduction are the turn-on condition (0.6-0.7V) of 0.84V greater than triode, and Q1 conducting Uo1 is output as 1; This moment, the Ub2 point was output as 0, and triode Q2 ends, and Uo2 is output as 1.

When single-chip microcomputer P1.0 is output as 1, the voltage 5V that Ub1 is ordered, the emitter voltage of Q1 triode is 5V, and the emitter of positive-negative-positive triode Q1 and base stage pressure reduction are 0V, do not satisfy the turn-on condition (0.6-0.7V) of triode, and Q1 is output as 0 by Uo1; This moment, the Ub2 point was output as (200/1200) * 5V=0.83V, and greater than the turn-on condition (0.6-0.7V) of triode, triode Q2 conducting is so Uo2 is output as 0.

When single-chip microcomputer P1.0 is changed to the input port, the P1.0 of single-chip microcomputer is in high-impedance state, be equivalent to open circuit, the voltage that Ub1 is ordered is (2200/2400) * 5V=4.58V, the emitter voltage of Q1 triode is 5V, the emitter of positive-negative-positive triode Q1 and base stage pressure reduction are the turn-on condition (0.6-0.7V) of 0.42V less than triode, and Q1 is output as 0 by Uo1; This moment, the Ub2 point was output as 0.41V, and triode Q2 ends, so Uo2 is output as 1.

Through above-mentioned conversion of signals, single-chip microcomputer P1.0 is extended to Uo1 and Uo2, and promptly the IO mouth of a single-chip microcomputer has been extended to two signal output parts, and output signal U o1, Uo2 have three kinds of array modes, is respectively 1,1; 0,0; 0,1.

Claims

1. the expanded circuit of a single-chip microcomputer IO mouth is characterized in that, it comprise first, second, third and fourth, five resistance and first and second triode, first and second triode is respectively positive-negative-positive triode and NPN type triode; One end of first and second resistance all is connected with the IO mouth of single-chip microcomputer, one end of the other end of first resistance and the 3rd resistance all is connected with the base stage of first triode, the other end of the emitter of first triode and the 3rd resistance all is connected with an end of the 5th resistance, one end of the 5th resistance also is connected with the working power of single-chip microcomputer, and the collector of first triode is as first signal output part; One end of the other end of second resistance and the 4th resistance all is connected with the base stage of second triode, the other end of the emitter of second triode and the 4th resistance all is connected with earth terminal, the collector of second triode is connected with the other end of the 5th resistance, and the collector of second triode is as the secondary signal output terminal; The single-chip microcomputer of described single-chip microcomputer for carrying out the appointment of I/O state separately to one of them IO mouth of single-chip microcomputer by its plug-in, and incoming level is the CMOS incoming level, output form is the CMOS three-state.

2. the expanded circuit of single-chip microcomputer IO mouth according to claim 1 is characterized in that, the resistance of first and second resistance equates, is 1K Ω; The resistance of third and fourth resistance equates, is 200 Ω; The resistance of the 5th resistance is 5.1K Ω; The input voltage of the working power of single-chip microcomputer is 5V.