Multi-serial-port communication control circuit

Abstract

The invention belongs to the technical field of liquid crystal screens, and particularly provides a multi-serial-port communication control circuit which comprises a universal serial bus (USB) to transistor-transistor logic (TTL) controller, a TTL-to-RS232 circuit, a TTL-to-RS485 circuit and a TTL-to-RS422 circuit, and the USB to TTL controller converts USB signals into four TTL signals; the TTL to RS232 conversion circuit is used for converting a TTL level signal into an RS232 level signal; the TTL-to-RS485 conversion circuit is used for converting a TTL level signal into an RS485 level signal; and the TTL to RS422 circuit is used for converting a TTL level signal into an RS422 level signal. According to the multi-serial-port communication control circuit provided by the invention, a USB signal is converted into a TTL signal through the USB-to-TTL controller, and the TTL signal is converted into common communication interfaces RS232, RS485 and RS422 through the level converter, so that debugging is convenient, and the multi-serial-port communication control circuit has good practical value.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid crystal screens, and in particular relates to a multi-serial port communication control circuit. Background Art

[0002] Generally speaking, LCD screens are greatly affected by changes in external ambient temperature, especially low temperature environments, due to their own material reasons. Generally, the operating temperature of LCD screens is 0~50℃, and the operating temperature of wide-temperature LCD screens is -20~70℃. Although most application scenarios can be met, many outdoor, industrial, and military products are currently affected by environmental factors, requiring LCD screens to work normally at -40℃ or even lower ambient temperatures. However, it is difficult to accurately control the heating temperature in the existing technology, and the error is large and nonlinear. On this basis, a multi-serial port communication control circuit is proposed. Summary of the invention

[0003] The present invention mainly provides a multi-serial port communication control circuit to solve the technical problems raised in the above background technology.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: A multi-serial port communication control circuit comprises a USB to TTL controller which is connected to a host via a USB interface. The USB to TTL controller converts USB signals into 4-channel TTL signals.

[0005] Further improvements are: 4-way TTL signal includes: TTL to RS232 circuit, used to convert TTL level into RS232 level for external communication; TTL to RS485 circuit, used to convert TTL level into RS485 level for external communication; TTL to RS422 circuit, used to convert TTL level into RS422 level for external communication; TLL, communicate directly with the outside world.

[0006] A further improvement is that the TTL to RS232 circuit includes a SIT3232EEUE level conversion chip, an ESD protection chip and a DB9 interface.

[0007] A further improvement is that the USB to TTL controller, the SIT3232EEUE level conversion chip, the ESD protection chip and the DB9 interface are connected in sequence to convert the USB signal into an RS232 signal.

[0008] A further improvement is that the TTL to RS485 circuit includes a SIT3485ESA level conversion chip, an ESD protection chip and a DB9 interface.

[0009] A further improvement is that the USB to TTL controller, the SIT3485ESA level conversion chip, the ESD protection chip and the DB9 interface are connected in sequence to convert the USB signal into an RS485 signal.

[0010] A further improvement is that the TTL to RS422 circuit includes a SIT3490EEUA level conversion chip, an ESD protection chip and a DB9 interface.

[0011] A further improvement is that the USB to TTL controller, the SIT3490EEUA level conversion chip, the ESD protection chip and the DB9 interface are connected in sequence to convert the USB signal into an RS422 signal.

[0012] A further improvement is that the USB to TTL controller is a CH334Q controller.

[0013] Among them, LED lights are added to the signal sending end, receiving end and power supply end, so that the working light can be turned on when the power is turned on, and the indicator light flashes when there is data transmission on the serial port, which is convenient for observing the indication function. Compared with the prior art, the present invention has the following beneficial effects: The multi-serial port communication control circuit provided by the present invention converts USB signals into TTL signals through a USB to TTL controller, and converts them into RS232, RS485, RS422 common communication interfaces through a level converter, which is convenient for debugging and has good practical value.

[0014] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a framework diagram of a multi-serial port communication control circuit provided by the present invention; Figure 2 It is a schematic diagram of a conversion circuit in a multi-serial port communication control circuit framework provided by the present invention; Figure 3 This is a schematic diagram of the connection of the indicator lights provided by the present invention. DETAILED DESCRIPTION

[0016] To facilitate understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings, but the present invention can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the content disclosed in the present invention more thorough and comprehensive.

[0017] like Figure 1-3As shown, the present invention provides a multi-serial port communication circuit, including: a USB to TTL controller, a TTL to RS232 circuit, a TTL to RS485 circuit, and a TTL to RS422 circuit.

[0018] Among them, the USB to TTL controller converts the USB signal into 4-way TTL signals; the TTL to RS232 circuit converts the TTL level signal into the RS232 level signal; the TTL to RS485 circuit converts the TTL level signal into the RS485 level signal; the TTL to RS422 circuit converts the TTL level signal into the RS422 level signal.

[0019] like Figure 2 As shown, the USB to TTL controller is connected to the host, the USB to TTL controller communicates with the host via USB, and converts the USB signal into 4-way TTL signals. The USB to TTL controller adopts the model CH334Q controller, and the model CH334Q controller performs the conversion of USB signals into TTL signals; the TTL to RS232 circuit includes the SIT3232EEUE level conversion chip, ESD protection chip, and DB9 interface; the TTL to RS485 circuit includes the SIT3485ESA level conversion chip, ESD protection chip, and DB9 interface; the TTL to RS422 circuit includes the SIT3490EEUA level conversion chip, ESD protection chip, and DB9 interface; Among them, the CH334Q controller, SIT3232EEUE level conversion chip, ESD protection chip, and DB9 interface are connected in sequence to convert USB signals into RS232 signals; the CH334Q controller, SIT3485ESA level conversion chip, ESD protection chip, and DB9 interface are connected in sequence to convert USB signals into RS485 signals; the CH334Q controller, SIT3490EEUA level conversion chip, ESD protection chip, and DB9 interface are connected in sequence to convert USB signals into RS422 signals.

[0020] like Figure 3 As shown, LED lights are added to the signal sending, receiving, and power supply ends, so that the working light can be turned on when the power is turned on, and the indicator light flashes when there is data transmission on the serial port, which is convenient for observing the indication function.

[0021] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-serial port communication control circuit, characterized in that: The control circuit comprises a USB to TTL controller, which is connected to a host through a USB interface. The USB to TTL controller converts USB signals into 4-channel TTL signals.

2. A multi-serial port communication control circuit according to claim 1, characterized in that: 4-channel TTL signals include: TTL to RS232 circuit, used to convert TTL level into RS232 level for external communication; TTL to RS485 circuit, used to convert TTL level into RS485 level for external communication; TTL to RS422 circuit, used to convert TTL level into RS422 level for external communication; TLL, communicate directly with the outside world.

3. A multi-serial port communication control circuit according to claim 1, characterized in that: The TTL to RS232 circuit includes a SIT3232EEUE level conversion chip, an ESD protection chip and a DB9 interface.

4. A multi-serial port communication control circuit according to claim 3, characterized in that: The USB to TTL controller, the SIT3232EEUE level conversion chip, the ESD protection chip and the DB9 interface are connected in sequence to convert the USB signal into an RS232 signal.

5. A multi-serial port communication control circuit according to claim 1, characterized in that: The TTL to RS485 circuit includes a SIT3485ESA level conversion chip, an ESD protection chip and a DB9 interface.

6. A multi-serial port communication control circuit according to claim 5, characterized in that: The USB to TTL controller, the SIT3485ESA level conversion chip, the ESD protection chip and the DB9 interface are connected in sequence to convert the USB signal into an RS485 signal.

7. A multi-serial port communication control circuit according to claim 1, characterized in that: The TTL to RS422 circuit includes a SIT3490EEUA level conversion chip, an ESD protection chip and a DB9 interface.

8. A multi-serial port communication control circuit according to claim 7, characterized in that: The USB to TTL controller, the SIT3490EEUA level conversion chip, the ESD protection chip and the DB9 interface are connected in sequence to convert the USB signal into an RS422 signal.

9. A multi-serial port communication control circuit according to any one of claims 1 to 8, characterized in that: The USB to TTL controller is a CH334Q controller.

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