CN212966162U - Multi-communication interface circuit - Google Patents
Multi-communication interface circuit Download PDFInfo
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- CN212966162U CN212966162U CN202022326414.7U CN202022326414U CN212966162U CN 212966162 U CN212966162 U CN 212966162U CN 202022326414 U CN202022326414 U CN 202022326414U CN 212966162 U CN212966162 U CN 212966162U
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Abstract
The utility model discloses a multi-communication interface circuit; including USB commentaries on classics serial circuits, RS-485 module circuit, RS-232 module circuit and RS-232 RS-485 send the selection circuit, including CH340G switching chip in the USB commentaries on classics serial circuits, including SP485E half-duplex transceiver in the RS-485 module circuit, including SP3232CSE transceiver in the RS-232 module circuit, RS-232 RS-485 sends and is equipped with two sets of LM339D four ways differential comparator on the selection circuit, the utility model discloses can carry out TTL to the level conversion between RS-485, also can carry out TTL to the level conversion between RS-232, but a board is multi-purpose to easy operation for different communication interfaces can realize quick the conversion, need not change the board again and carry out the conversion connection between the different communication interfaces.
Description
Technical Field
The utility model belongs to the technical field of communication interface circuit, concretely relates to many communication interface circuit.
Background
In the current industrial control technology, the requirement of a plurality of devices is difficult to meet only through single-chip microcomputer for one-way control, because a plurality of devices need to input external information and output own operation parameters and states to the outside. This requires that a plurality of devices communicate with each other to ensure bidirectional data transmission. The most commonly used serial port communication in the application field bus is RS-485 and RS-232. When the serial port is connected with RS-485/RS-232 for communication, level conversion from TTL to RS-485/RS-232 is needed, however, various communication interface circuits on the market still have various problems.
Although the scheme is implemented, the communication interface switching circuit of the multiple optical modules, disclosed in the publication No. CN205608716U, enables the host to communicate with the multiple optical modules, simplifies the software and hardware design, and reduces the cost; the scheme can be expanded according to the number of different optical modules, the practicability and the universality are high, but the problem that the existing communication interface circuit board cannot realize level conversion among different communications is not solved, and a multi-communication interface circuit is provided for the purpose.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a many communication interface circuit to solve the problem that proposes among the above-mentioned background art.
In order to achieve the above object, the utility model provides a following technical scheme: a multi-communication interface circuit comprises a USB-to-serial port circuit, an RS-485 module circuit, an RS-232 module circuit and an RS-232/RS-485 sending selection circuit,
the USB-to-serial port circuit comprises a CH340G switching chip, the CH340G switching chip is electrically connected with a USB-S2 serial interface, and a crystal oscillator chip Y3 is connected between pins 7 and 8 of the CH340G switching chip in series;
the RS-485 module circuit comprises an SP485E half-duplex transceiver, and four-pin connectors are electrically connected to pins 7 and 6 of the SP485E half-duplex transceiver;
the RS-232 module circuit comprises an SP3232CSE transceiver, four-pin connectors are electrically connected to pins 14 and 13 of the SP3232CSE transceiver, a capacitor C51 is connected in series between pins 1 and 2 of the SP3232CSE transceiver, and a capacitor C52 is connected in series between pins 4 and 5 of the SP3232CSE transceiver;
the RS-232/RS-485 transmitting selection circuit is provided with two sets of LM339D four-way differential comparators, the two sets of LM339D four-way differential comparators are electrically connected, and one end of each of the two sets of LM339D four-way differential comparators is respectively and electrically connected with a resistor R39, a resistor R43 and a capacitor C49.
Preferably, a capacitor C38 is electrically connected to the 4 pins of the CH340G adapter chip, the capacitor C38 is electrically grounded, and two ends of the crystal oscillator Y3 are respectively electrically connected to the capacitor C40 and the capacitor C41.
Preferably, a capacitor 48 is electrically connected between the pin 8 and the pin 5 of the SP485E half-duplex transceiver, one end of the capacitor 48 is electrically connected to the pin 6 of the SP485E half-duplex transceiver through a resistor R25, and the other end of the capacitor C48 is electrically connected to the pin 7 of the SP485E half-duplex transceiver through a resistor R44.
Preferably, a capacitor C50 is electrically connected to the VDD pin of the SP3232CSE transceiver, and the capacitor C50 is electrically grounded.
Preferably, the 2 pin of the SP3232CSE transceiver is electrically connected to the VSS terminal of the SP3232CSE transceiver through a capacitor C54, and the 6 pin of the SP3232CSE transceiver is electrically connected to the VSS terminal of the SP3232CSE transceiver through a capacitor C53.
Preferably, the resistor R43 of the RS-232/RS-485 transmitting selection circuit is connected in parallel with the capacitor C49, and the resistor R43 is electrically grounded to one end of the capacitor C49.
Preferably, a resistor R45 is electrically connected to one group of LM339D four-way differential comparators.
Preferably, the USB-S2 serial interface and the four-pin plug have pins electrically connected to ground.
Compared with the prior art, the beneficial effects of the utility model are that:
the utility model discloses can carry out TTL to the level conversion between RS-485, also can carry out TTL to the level conversion between RS-232, but a board is multi-purpose to easy operation for different communication interface can realize quick the conversion, need not trade the board again and carry out the conversion connection between the different communication interface.
Drawings
FIG. 1 is a schematic diagram of a USB-to-serial port circuit of the present invention;
FIG. 2 is a schematic circuit diagram of an RS-485 module of the present invention;
FIG. 3 is a schematic circuit diagram of an RS-232 module according to the present invention;
fig. 4 is a schematic diagram of the RS-232/RS-485 transmission selection circuit of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Referring to fig. 1-4, the present invention provides a technical solution: a multi-communication interface circuit comprises a USB-to-serial port circuit, an RS-485 module circuit, an RS-232 module circuit and an RS-232/RS-485 sending selection circuit,
the USB-to-serial port circuit comprises a CH340G switching chip, the CH340G switching chip is electrically connected with a USB-S2 serial interface, and a crystal oscillator chip Y3 is connected between pins 7 and 8 of the CH340G switching chip in series;
the RS-485 module circuit comprises an SP485E half-duplex transceiver, and four-pin connectors are electrically connected to pins 7 and 6 of the SP485E half-duplex transceiver;
the RS-232 module circuit comprises an SP3232CSE transceiver, four-pin connectors are electrically connected to pins 14 and 13 of the SP3232CSE transceiver, a capacitor C51 is connected in series between pins 1 and 2 of the SP3232CSE transceiver, and a capacitor C52 is connected in series between pins 4 and 5 of the SP3232CSE transceiver;
the RS-232/RS-485 transmitting selection circuit is provided with two sets of LM339D four-way differential comparators, the two sets of LM339D four-way differential comparators are electrically connected, and one end of each of the two sets of LM339D four-way differential comparators is respectively and electrically connected with a resistor R39, a resistor R43 and a capacitor C49.
When in use: the circuit is firstly connected with a USB-S2 serial interface through a CH340G switching chip, and because only one transmitting object and a plurality of receiving objects can be arranged in the serial port in the communication process, when the RS-485/RS-232 transmitting selection circuit is in a transmitting state, only one transmitting object can be in a transmitting state, and the other transmitting object is in an idle state, the following specific processes of transmitting and receiving are as follows:
(1) the TTL module is in a sending state, and the RS-485 module circuit and the RS-232 module are in a receiving state;
when the COM _ TX is at a low level, the TTL module is at a transmitting state, and in the RS-485 module circuit, the COM _ TX outputs a high level (but the level is weak, the driving capability is not available) at a VcomDE point through the comparator U55A, and at this time, the RS-485 module is at a receiving state. For the RS-232 module circuit, pins 10 and 11 are low and in a receiving state.
(2) The TTL module is in a receiving state, and only one of the RS-485 module circuit and the RS-232 module circuit is in a sending state;
when the RS-485 module circuit is in a transmitting state and the RS-232 module circuit is in an idle state, the COM _485R is in a low level, the R232Rx is in a high level, the COM _ Rx passes through the comparator U55C to output the low level, the COM _ Rx is pulled to the high level by the pull-up resistor R45, the R232Rx passes through the comparator U55B, the output end is cut off, therefore, the COM _ Rx is in the high level, the TTL is in a receiving state, and the information transmitted by the RS-485 module circuit begins to be received. When the RS-232 module circuit is in a transmitting state and the RS-485 module circuit is in a receiving state, R232Rx is in a low level, COM _ Rx is in a high level, R232Rx outputs the low level when passing through a comparator U55B, COM _ Rx passes through a comparator U55C, an output tube is cut off, TTL is in a receiving state, and information transmitted by the RS-232 module circuit is received.
In order to protect the CH340G adapter chip and prevent the CH340G adapter chip from being damaged during operation, in this embodiment, preferably, the 4 pins of the CH340G adapter chip are electrically connected to a capacitor C38, the capacitor C38 is electrically grounded, and two ends of the crystal oscillator Y3 are respectively electrically connected to a capacitor C40 and a capacitor C41.
In order to transmit and receive signals to and from the SP485E half-duplex transceiver and ensure stable operation of the SP485E half-duplex transceiver, in this embodiment, preferably, a capacitor 48 is electrically connected between the pin 8 and the pin 5 of the SP485E half-duplex transceiver, one end of the capacitor 48 is electrically connected to the pin 6 of the SP485E half-duplex transceiver through a resistor R25, and the other end of the capacitor C48 is electrically connected to the pin 7 of the SP485E half-duplex transceiver through a resistor R44.
In order to protect the SP3232CSE transceiver and achieve stable operation, in this embodiment, preferably, a VDD pin of the SP3232CSE transceiver is electrically connected to a capacitor C50, the capacitor C50 is electrically grounded, a pin 2 of the SP3232CSE transceiver is electrically connected to a VSS terminal of the SP3232CSE transceiver through a capacitor C54, and a pin 6 of the SP3232CSE transceiver is electrically connected to the VSS terminal of the SP3232CSE transceiver through a capacitor C53.
In order to protect the RS-232/RS-485 transmission selection circuit, in this embodiment, preferably, the resistor R43 on the RS-232/RS-485 transmission selection circuit is connected in parallel with the capacitor C49, and the resistor R43 and one end of the capacitor C49 are electrically grounded.
In order to realize the selection of different communications, in this embodiment, preferably, a resistor R45 is electrically connected to one group of the LM339D four-way differential comparators.
In order to protect the USB-S2 serial interface and the four-pin plug, in this embodiment, it is preferable that the USB-S2 serial interface and the four-pin plug have pins electrically grounded.
The utility model discloses a theory of operation and use flow: when in use: the circuit is firstly connected with a USB-S2 serial interface through a CH340G switching chip, and because only one transmitting object and a plurality of receiving objects can be arranged in the serial port in the communication process, when the RS-485/RS-232 transmitting selection circuit is in a transmitting state, only one transmitting object can be in a transmitting state, and the other transmitting object is in an idle state, the following specific processes of transmitting and receiving are as follows:
(1) the TTL module is in a sending state, and the RS-485 module circuit and the RS-232 module are in a receiving state;
when the COM _ TX is at a low level, the TTL module is at a transmitting state, and in the RS-485 module circuit, the COM _ TX outputs a high level (but the level is weak, the driving capability is not available) at a VcomDE point through the comparator U55A, and at this time, the RS-485 module is at a receiving state. For the RS-232 module circuit, pins 10 and 11 are low and in a receiving state.
(2) The TTL module is in a receiving state, and only one of the RS-485 module circuit and the RS-232 module circuit is in a sending state;
when the RS-485 module circuit is in a transmitting state and the RS-232 module circuit is in an idle state, the COM _485R is in a low level, the R232Rx is in a high level, the COM _ Rx passes through the comparator U55C to output the low level, the COM _ Rx is pulled to the high level by the pull-up resistor R45, the R232Rx passes through the comparator U55B, the output end is cut off, therefore, the COM _ Rx is in the high level, the TTL is in a receiving state, and the information transmitted by the RS-485 module circuit begins to be received. When the RS-232 module circuit is in a transmitting state and the RS-485 module circuit is in a receiving state, R232Rx is in a low level, COM _ Rx is in a high level, R232Rx outputs the low level when passing through a comparator U55B, COM _ Rx passes through a comparator U55C, an output tube is cut off, TTL is in a receiving state, and information transmitted by the RS-232 module circuit is received.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (8)
1. A multi-communication interface circuit comprises a USB-to-serial port circuit, an RS-485 module circuit, an RS-232 module circuit and an RS-232/RS-485 sending selection circuit, and is characterized in that:
the USB-to-serial port circuit comprises a CH340G switching chip, the CH340G switching chip is electrically connected with a USB-S2 serial interface, and a crystal oscillator chip Y3 is connected between pins 7 and 8 of the CH340G switching chip in series;
the RS-485 module circuit comprises an SP485E half-duplex transceiver, and four-pin connectors are electrically connected to pins 7 and 6 of the SP485E half-duplex transceiver;
the RS-232 module circuit comprises an SP3232CSE transceiver, four-pin connectors are electrically connected to pins 14 and 13 of the SP3232CSE transceiver, a capacitor C51 is connected in series between pins 1 and 2 of the SP3232CSE transceiver, and a capacitor C52 is connected in series between pins 4 and 5 of the SP3232CSE transceiver;
the RS-232/RS-485 transmitting selection circuit is provided with two sets of LM339D four-way differential comparators, the two sets of LM339D four-way differential comparators are electrically connected, and one end of each of the two sets of LM339D four-way differential comparators is respectively and electrically connected with a resistor R39, a resistor R43 and a capacitor C49.
2. The multi-communication interface circuit of claim 1, wherein: the 4 pins of the CH340G adapting chip are electrically connected with a capacitor C38, the capacitor C38 is electrically grounded, and two ends of the crystal oscillator Y3 are respectively electrically connected with a capacitor C40 and a capacitor C41.
3. The multi-communication interface circuit of claim 1, wherein: the electric connection between the 8 pins and the 5 pins of the SP485E half-duplex transceiver is provided with a capacitor 48, one end of the capacitor 48 is electrically connected with the 6 pins of the SP485E half-duplex transceiver through a resistor R25, and the other end of the capacitor C48 is electrically connected with the 7 pins of the SP485E half-duplex transceiver through a resistor R44.
4. The multi-communication interface circuit of claim 1, wherein: the VDD pin of the SP3232CSE transceiver is electrically connected with a capacitor C50, and the capacitor C50 is electrically grounded.
5. The multi-communication interface circuit of claim 1, wherein: the 2 pin of the SP3232CSE transceiver is electrically connected with the VSS end of the SP3232CSE transceiver through a capacitor C54, and the 6 pin of the SP3232CSE transceiver is electrically connected with the VSS end of the SP3232CSE transceiver through a capacitor C53.
6. The multi-communication interface circuit of claim 1, wherein: the resistor R43 on the RS-232/RS-485 transmitting selection circuit is connected with the capacitor C49 in parallel, and the resistor R43 and one end of the capacitor C49 are electrically grounded.
7. The multi-communication interface circuit of claim 1, wherein: and a resistor R45 is electrically connected to one group of LM339D four-way differential comparators.
8. The multi-communication interface circuit of claim 1, wherein: pins of the USB-S2 serial interface and the four-pin plug are electrically grounded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022326414.7U CN212966162U (en) | 2020-10-19 | 2020-10-19 | Multi-communication interface circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022326414.7U CN212966162U (en) | 2020-10-19 | 2020-10-19 | Multi-communication interface circuit |
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| Publication Number | Publication Date |
|---|---|
| CN212966162U true CN212966162U (en) | 2021-04-13 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202022326414.7U Active CN212966162U (en) | 2020-10-19 | 2020-10-19 | Multi-communication interface circuit |
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| CN (1) | CN212966162U (en) |
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