MCU (Microprogrammed Control Unit) and NB (Narrow Band) module communication level conversion circuit

Abstract

The utility model relates to the technical field of electronic circuits, in particular to an MCU (Microprogrammed Control Unit) and NB (Narrow Band) module communication level conversion circuit, which is used for realizing communication between an MCU and an NB module, the working power supply of the MCU is 3.3 V, and the TTL (Transistor-Transistor Logic) level of the module is 1.8 V. The circuit is characterized in that the TTL communication level conversion circuit comprises a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a diode and a triode Q1; one end of the resistor R1 is connected with an RXD end of the NB module and is also connected with an anode of the diode D1, the other end of the resistor R1 is connected with a 1.8 V power supply, and a cathode of the diode D1 is connected with a TXD end of the MCU; one end of the resistor R2 is connected with a 3.3 V power supply, and the other end of the resistor R2 is connected with the RXD end of the MCU and the collector of the triode Q1; the emitter of the triode Q1 is connected with the TXD end of the NB module, the resistor R3 and the capacitor C1 are connected in parallel, and then one end is connected with the base of the triode Q1. The level conversion circuit is simple in structure, stable in operation and high in conversion accuracy, the purpose of level conversion can be achieved with low cost, and meanwhile the stability of the circuit is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, and in particular to a communication level conversion circuit between an MCU and a NB module. Background Art

[0002] The existing level conversion circuit composed of two transistors has the following problems: it uses many components, has a high design cost, occupies more PCB space, and brings trouble to designers; it occupies a lot of PCB space resources and is easily interfered by uncertain factors, which will cause communication data loss and incompleteness.

[0003] To this end, the present application designs a communication level conversion circuit between MCU and NB module to solve the above problems. Utility Model Content

[0004] In order to make up for the deficiencies in the prior art, the utility model provides a communication level conversion circuit between an MCU and a NB module.

[0005] A communication level conversion circuit between an MCU and a NB module is used to realize communication between the MCU and the NB module, wherein the working power supply of the MCU is 3.3V and the TTL level of the module is 1.8V; the characteristic of the circuit is that the TTL communication level conversion circuit comprises a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a diode and a transistor Q1; one end of the resistor R1 is connected to the RXD end of the NB module and the anode of the diode D1, the other end of the resistor R1 is connected to the 1.8V power supply, and the cathode of the diode D1 is connected to the TXD end of the MCU; one end of the resistor R2 is connected to the 3.3V power supply, and the other end is connected to the RXD end of the MCU and the collector of the transistor Q1; the emitter of the transistor Q1 is connected to the TXD end of the NB module, the resistor R3 and the capacitor C1 are connected in parallel, and then one end is connected to the base of the transistor Q1.

[0006] Furthermore, in order to better implement the utility model, the MCU and NB module communication level conversion circuit also includes a diode D1 connected to the TXD end of the MCU and the RXD end of the NB module, wherein the cathode of the diode D1 is connected to the TXD end of the MCU, and the anode is connected to the RXD end of the NB module, and the resistor R1 is connected to the RXD end of the NB module to pull up the level to 1.8V voltage.

[0007] Furthermore, in order to better implement the present invention, the MCU and NB module communication level conversion circuit also includes a filter capacitor C1 connected in parallel to both ends of the resistor R3.

[0008] The beneficial effects of the utility model are:

[0009] The utility model has a simple structure, stable operation, high conversion accuracy, can achieve the purpose of level conversion at a relatively low cost, and simultaneously increases the stability of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is the communication level conversion circuit diagram of the MCU and NB module of the utility model;

[0011] Figure 2 This is a TTL communication level conversion circuit diagram of the utility model. DETAILED DESCRIPTION

[0012] 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 some embodiments of the utility model, not all embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0013] Therefore, the following detailed description of the embodiments of the utility model provided in the accompanying drawings is not intended to limit the scope of the utility model claimed for protection, but merely represents 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 efforts are within the scope of protection of the utility model.

[0014] Figure 1-Figure 2 A specific embodiment of the utility model is a level conversion circuit for communication between an MCU and a NB module. Figure 1 As shown, the MCU and NB module communication level conversion circuit provided in this embodiment is used for the communication between the MCU with a 3.3V voltage and the NB module with a 1.8V TTL level voltage, and the TTL voltage of the MCU is different from the TTL voltage of the NB module, the TTL voltage of the MCU is 3.3V, and the TTL voltage of the NB module is 1.8V. This embodiment uses this TTL communication level conversion circuit to achieve communication between different voltages of the MCU and the NB module.

[0015] like Figure 2As shown, the TTL communication level conversion circuit provided in this embodiment includes a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a diode, and a transistor Q1, wherein one end of the resistor R1 is connected to the RXD end of the NB module, and the other end is connected to a 1.8V power supply, and the resistor R1 is connected to the anode of the diode D1; it can be seen that the resistor R1 plays a role of pulling up the level, and the diode is unidirectionally turned on, so that the level of the RXD of the NB module changes between 0 and 1.8V. In addition, one end of the resistor R2 is connected to 3.3V, and the other end is connected to the collector of the transistor Q1 and the RXD end of the MCU; the emitter of the transistor Q1 is connected to the TXD end of the NB module; one end of the resistor R3 is connected to 1.8V, and the other end is connected to the base of the transistor Q1, and the capacitor C1 is connected in parallel to the two ends of the resistor R3 as a filter capacitor.

[0016] The working state of the above TTL communication level conversion circuit is described as follows:

[0017] The TXD end of the MCU sends "1", that is, it outputs a high level of 3.3V. The cathode voltage of the diode D1 is greater than the anode voltage, and the diode is reversely cut off. The voltage of the RXD end of the NB module is 1.8V after the pull-up resistor R1, that is, "1" is received.

[0018] The TXD end of the MCU sends "0", that is, the output is low level, the cathode of the diode is 0V, and the voltage of the anode through the pull-up resistor R1 is 1.8V. At this time, the diode is forward-conducted, and the voltage of the RXD end of the NB module will be low level, that is, "0" is received.

[0019] The TXD of the NB module sends "1", that is, outputs a high level. The emitter voltage and base voltage of transistor Q1 are equal, transistor Q1 is not turned on, and the RXD voltage of the MCU will receive a high level of 3.3V through the pull-up resistor R2, that is, it receives "1".

[0020] The NB module sends "0", the base voltage of the transistor is 1.8V greater than the emitter voltage, the transistor Q1 is turned on, the collector voltage of the transistor is low, and the MCU will receive "0".

[0021] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the utility model by ordinary technicians in this field should be included in the scope of the claims of the utility model as long as they do not depart from the spirit and scope of the technical solution of the utility model.

Claims

1. A communication level conversion circuit between an MCU and a NB module, including a TTL communication level conversion circuit, characterized in that: The TTL communication level conversion circuit connects the MCU and the NB module, the working power supply of the MCU is 3.3V, the TTL level of the NB module is 1.8V, and the TTL communication level conversion circuit includes a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a diode D1, and a transistor Q1.

2. The MCU and NB module communication level conversion circuit according to claim 1, characterized in that: One end of the resistor R1 is connected to the RXD end of the NB module and the anode of the diode D1. The other end of the resistor R1 is connected to the 1.8V power supply, and the cathode of the diode D1 is connected to the TXD end of the MCU. One end of the resistor R2 is connected to the 3.3V power supply, and the other end is connected to the RXD end of the MCU and the collector of the transistor Q1. The emitter of the transistor Q1 is connected to the TXD end of the NB module. The resistor R3 and the capacitor C1 are connected in parallel, and then one end is connected to the base of the transistor Q1, and the other end is connected to the 1.8V power supply.

3. The MCU and NB module communication level conversion circuit according to claim 1, characterized in that: The diode D1 is connected to the TXD end of the MCU and the RXD end of the NB module, wherein the cathode of the diode D1 is connected to the TXD end of the MCU, and the anode is connected to the RXD end of the NB module. Meanwhile, the resistor R1 is connected to the RXD end of the NB module to pull up the voltage level to 1.8V.

4. The MCU and NB module communication level conversion circuit according to claim 1, characterized in that: The capacitor C1 is a filter capacitor connected in parallel to the resistor R3.

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