Character liquid crystal device based on USB interface

Abstract

The utility model discloses a character liquid crystal device based on a USB (Universal Serial Bus) interface, which comprises a character liquid crystal display module, a CPLD (Complex Programmable Logic Device) controller module and a USB to UART (Universal Asynchronous Receiver / Transmitter) interface module, the CPLD controller module is in one-way communication connection with the character liquid crystal display module, and the CPLD controller module is in two-way communication connection with the USB to UART interface module; and a USB interface of the USB-to-UART interface module is used as a power supply interface of the character liquid crystal device. According to the character liquid crystal device provided by the utility model, the communication with an upper computer is realized through the USB to UART interface module, the power is supplied through the USB interface, the data communication is not realized by adopting an RS-232 serial interface any more, the long-distance transmission of the data communication is realized, a power adapter is not needed, the plug-and-play is realized, the use cost is reduced, and the CPLD controller module is adopted, so that the character liquid crystal device is convenient to use. And the stability and the reliability of the character liquid crystal device are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of liquid crystal devices, in particular to a character liquid crystal device based on a USB interface. Background Art

[0002] Character LCDs are widely used in electronic devices, household appliances, automobiles, medical equipment and many other fields. The commonly used LCD model of character liquid crystal devices is LCD1602, and an MCU based on Harvard structure is usually used to implement LCD1602 initialization, read and write operations and other instructions. The display content is determined by the host computer, and data communication is achieved using serial interfaces such as RS-232. The host computer can be a PC or an embedded host.

[0003] The above-mentioned character liquid crystal device based on RS-232 interface and Harvard structure MCU has several obvious technical defects and deficiencies:

[0004] First, with the development of computer interface technology, more and more PCs have abandoned the traditional RS-232 serial communication interface, making the devices based on this type of interface unusable;

[0005] Second, the theoretical transmission distance of the RS-232 interface is limited. In actual use, the transmission distance will be shorter depending on the interface capacitance, cable quality, etc., and cannot meet some long-distance transmission requirements;

[0006] Third, the character LCD device needs a separate power adapter to power it, which not only increases the cost of use, but also makes it inconvenient to get power in many places on industrial sites, further limiting its application scope;

[0007] Fourth, today's electronic devices are all striving to be more stable and reliable, and the stability and reliability of character liquid crystal devices also need to be improved.

[0008] In view of this, it is necessary to provide a character liquid crystal device based on a USB interface to overcome the shortcomings of the prior art. Summary of the invention

[0009] The utility model aims to provide a character liquid crystal device based on a USB interface, which has the characteristics of convenient use, low use cost, wide application range, ability to meet the requirements of long-distance transmission, high stability and the like.

[0010] In order to achieve the above-mentioned purpose, the utility model provides a character liquid crystal device based on a USB interface, comprising: a character liquid crystal display module, a CPLD controller module, and a USB to UART interface module, wherein the CPLD controller module is connected to the character liquid crystal display module by unidirectional communication, and the CPLD controller module is connected to the USB to UART interface module by bidirectional communication; the USB interface of the USB to UART interface module serves as a power supply interface of the character liquid crystal device.

[0011] In a preferred embodiment, it also includes a USB cable connecting the USB to UART interface module.

[0012] In a preferred embodiment, the CPLD controller module is connected to the character liquid crystal display module via a 16-bit terminal block.

[0013] In a preferred embodiment, the character liquid crystal display module includes instruction and data selection pins, read and write control pins, and data enable control pins.

[0014] In a preferred embodiment, the character liquid crystal display module adopts LCD1602.

[0015] In a preferred embodiment, the CPLD controller module uses a 5M160ZE64C5N chip.

[0016] In a preferred embodiment, the USB to UART interface module uses a FT232R chip.

[0017] Compared with the prior art, the beneficial effects of the character liquid crystal device based on the USB interface of the utility model are:

[0018] A character liquid crystal device based on a USB interface realizes communication with a host computer through a USB to UART interface module, connects a character liquid crystal display module and a USB to UART interface module through a CPLD controller module, and is powered by the USB interface. With such a design, data communication is no longer implemented using an RS-232 serial interface, thereby realizing long-distance data communication transmission. USB power supply is adopted, and no power adapter is required, which is plug-and-play and solves the problem of power supply. This can greatly save the use cost of the character liquid crystal device, and is also convenient for power supply in industrial sites and other places. Compared with an MCU based on a Harvard structure, since the target file of the CPLD controller module is a netlist file, which is equivalent to an actual hardware circuit, the stability and reliability of the character liquid crystal device 100 are improved.

[0019] In order to make the above-mentioned objects, features and advantages of the utility model more obvious and easy to understand, the preferred embodiments of the utility model are given below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic diagram of the connection relationship of a character liquid crystal device based on a USB interface provided by the utility model;

[0022] Figure 2 The circuit of the CPLD controller module;

[0023] Figure 3 This is the circuit of the character liquid crystal display module.

[0024] Figure 4 A circuit for a USB to UART interface module;

[0025] Among them, 100, character liquid crystal device, 10, CPLD controller module, 20, character liquid crystal display module, 30, USB to UART interface module, 40, USB line. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only a part of the embodiments of the utility model, rather than all the embodiments. The components of the embodiments of the utility model generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the utility model claimed for protection, but merely represents the selected embodiments of the utility model. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the utility model.

[0027] In an embodiment of the present invention, a character liquid crystal device 100 based on a USB interface is provided.

[0028] See also Figure 1A character liquid crystal device 100 based on a USB interface comprises: a character liquid crystal display module 20, a CPLD controller module 10, and a USB to UART interface module 30. The CPLD controller module 10 is connected to the character liquid crystal display module 20 in a unidirectional communication manner, and the CPLD controller module 10 is connected to the USB to UART interface module 30 in a bidirectional communication manner. The USB interface of the USB to UART interface module 30 serves as a power supply interface of the character liquid crystal device 100.

[0029] In the present embodiment, the character liquid crystal display module 20 is of model LCD1602, which can display 2 lines with 32 characters in total, adopts a 16-bit standard interface, and supports similar products of most manufacturers on the market. LCD1602 can also adopt a 14-bit interface, the main difference being 2 backlight control pins. In addition to the main power supply and contrast adjustment function pins, other function pins of LCD1602 also include an 8-bit data port, an instruction / data control pin RS (also referred to as an instruction and data selection pin), a read-write control pin RW, and a data enable control pin DEN. All function pins are sampled when the data enable signal is at a high level, and their functions are determined by the combination of each pin. Further, the character liquid crystal display module 20 also has an interface DATA for multiplexing instructions and target data.

[0030] In this embodiment, the CPLD controller module 10 includes an interface adapter to which the character liquid crystal display module 20 is connected.

[0031] The CPLD controller module 10 communicates unidirectionally with the character liquid crystal display module 20 , and the CPLD controller module 10 can transmit data to the character liquid crystal display module 20 .

[0032] The CPLD controller module 10 includes a character liquid crystal control output circuit, which can perform display control and initialization control on the character liquid crystal display module 20 , and specifically, can implement instructions such as initialization, read and write operations, etc. of the character liquid crystal display module 20 .

[0033] Furthermore, the CPLD controller module 10 includes a UART control circuit connected to the USB to UART interface module 30 .

[0034] Specifically, the specific model of the CPLD controller module 10 is 5M160ZE64C5N, which is a low-cost general-purpose programmable logic device launched by Altera Corporation of the United States. It contains 160 LE logic resources and the comprehensive utilization rate can reach 92%.

[0035] Specifically, the USB to UART interface module 30 uses the FT232R chip, which is a USB to UART bridge chip launched by FTDI. The chip integrates a USB protocol processor and can quickly implement USB-based serial communication functions without firmware programming.

[0036] In this embodiment, the USB to UART interface module 30 is connected to a USB line 40. The character liquid crystal device 100 is powered by the USB line 40. The USB interface is used to connect to a host computer and also serves as a power supply interface. The host computer sends a display request through the USB interface. The host computer can be a PC or an embedded host.

[0037] The USB to UART interface module 30 is responsible for the conversion of the physical interface. The UART interface of the USB to UART interface module 30 is connected to the CPLD controller module 10. The USB to UART interface module 30 and the CPLD controller module 10 communicate bidirectionally (information reception RX and information transmission TX). The CPLD controller module 10 can respond to the request, receive data through the UART and complete data conversion, and finally send the data to the character liquid crystal display module 20 to complete a display process.

[0038] In a preferred embodiment, the mechanical size of the CPLD controller module 10 is consistent with that of the character liquid crystal display module 20. The CPLD controller module 10 and the character liquid crystal display module 20 are connected via a 16-bit terminal block to form a whole for easy placement.

[0039] This embodiment further includes a USB cable 40 connected to the USB to UART interface module 30 , and the character liquid crystal device 100 is connected to the PC via the single USB cable 40 .

[0040] See also Figure 2 , is a schematic diagram of an implementation of the CPLD controller module 10, Figure 2 The CPLD controller module 10 is divided into four submodules, namely, U2A, U2B, U2C and U2D, for example. Figure 3 , is a circuit of the character liquid crystal display module 20. Figure 4 This is a circuit of the USB to UART interface module 30 .

[0041] In summary, a character liquid crystal device 100 based on a USB interface realizes communication with a host computer through a USB to UART interface module 30, and data communication is no longer realized by using an RS-232 serial interface, thereby realizing long-distance transmission of data communication; USB power is adopted through the USB to UART interface, and no power adapter is required, plug and play is used, and the problem of power supply is solved, which can greatly save the use cost of the character liquid crystal device 100, and it is also convenient to obtain power in places such as industrial sites. By adopting a USB to UART interface, power supply is convenient and the transmission distance is long, which makes it very convenient to use. By adopting a CPLD controller module 10, compared with an MCU based on a Harvard structure, because the target file of the CPLD controller module 10 is a netlist file, which is equivalent to an actual hardware circuit, the stability and execution efficiency are better, and the stability and reliability of the character liquid crystal device 100 are improved. Compared with a traditional character liquid crystal device 100 based on an RS-232 interface and a Harvard structure MCU, the character liquid crystal device 100 of the utility model based on a USB interface has the characteristics of convenient use, low cost, stronger applicability, and a wide range of applications.

[0042] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A character liquid crystal device based on a USB interface, characterized in that: include: A character liquid crystal display module, a CPLD controller module, and a USB to UART interface module. The CPLD controller module is connected to the character liquid crystal display module in a unidirectional communication manner, and the CPLD controller module is connected to the USB to UART interface module in a bidirectional communication manner. The USB interface of the USB to UART interface module serves as a power supply interface for the character liquid crystal device.

2. A character liquid crystal device based on a USB interface as claimed in claim 1, characterized in that: Also included is a USB cable connecting the USB to UART interface module.

3. A character liquid crystal device based on a USB interface as claimed in claim 1, characterized in that: The CPLD controller module is connected to the character liquid crystal display module via a 16-bit terminal block.

4. A character liquid crystal device based on a USB interface as claimed in claim 1, characterized in that: The character liquid crystal display module includes instruction and data selection pins, read and write control pins and data enable control pins.

5. A character liquid crystal device based on a USB interface as claimed in claim 1, characterized in that: The character liquid crystal display module adopts LCD1602.

6. A character liquid crystal device based on a USB interface as claimed in claim 1, characterized in that: The CPLD controller module adopts a 5M160ZE64C5N chip.

7. A character liquid crystal device based on a USB interface as claimed in claim 1, characterized in that: The USB to UART interface module adopts the FT232R chip.

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