Circuit of serial port receiving and transmitting data control indicating lamp
By designing a serial port data transmission and reception control indicator circuit, the RC circuit is used to delay the transistor switch state, which solves the problem that the indicator light cannot clearly indicate when the data volume is small or the interval is long, and achieves a clear indication effect under different conditions.
Patent Information
- Application Number
- CN202422051372.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-23
- Publication Date
- 2025-08-12
- Estimated Expiration
- 2034-08-23
AI Technical Summary
In the prior art, when the data volume is small or the interval is long, the indicator light cannot clearly indicate the serial port sending and receiving status.
A serial port data transmission and reception control indicator light circuit is adopted to delay the switching state of the transistor through different times, and the RC circuit is used to control the flashing effect of the indicator light.
When the data volume is small or the transfer time interval is long, the indicator light can clearly flash to indicate the serial port's sending and receiving status.
Smart Images
Figure CN223219247U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of data communication indication, in particular to a circuit for controlling an indicating light for sending and receiving data at a serial port. Background Art
[0002] Many products have multiple serial ports, requiring indicator lights to indicate the status of serial port data transmission. Existing hardware serial port lighting systems connect the received and transmitted data to the base of a transistor and control the on / off switching of the transistor to illuminate the indicator light. This approach has the drawback that if the data volume is very small or the interval between data transmissions is large, the transistor conduction time is very short, causing the indicator light to either not illuminate or remain permanently on. Therefore, it is essential to design a hardware-based circuit to implement serial port transmit and receive indicators, providing real-time indication of the serial port's transmit and receive status. Utility Model Content
[0003] The purpose of the utility model is to provide a circuit for controlling an indicator light by sending and receiving data via a serial port, so as to solve the problem in the prior art that the indicator light cannot clearly indicate when the amount of data is small or the interval time is long.
[0004] To achieve the above object, the technical solution adopted by the present invention is as follows: providing a circuit for controlling an indicator light for receiving and sending data via a serial port, comprising an indicator light LED1, wherein an anode of the indicator light LED1 is connected to a power supply VCC, a cathode of the indicator light LED1 is connected to one end of a third resistor R3, the other end of the third resistor R3 is connected to an emitter of a second transistor Q2, and a collector of the second transistor Q2 is grounded;
[0005] The base set of the second transistor Q2 is connected to one end of the second resistor R2, the other end of the second resistor R2 is commonly connected to one end of the first capacitor C1 and the emitter of the first transistor Q1, and the other end of the first capacitor C1 is grounded; the collector of the first transistor Q1 is grounded, the base set of the first transistor Q1 is connected to one end of the first resistor R1, and the other end of the first resistor R1 is connected to the transmit / receive pin TX / RX of the chip.
[0006] Preferably, in this technical solution, the model of the first transistor Q1 is PMBT3906; the model of the second transistor Q2 is PMBT3906.
[0007] Preferably, in this technical solution, the resistance of the first resistor R1 is 1KΩ, and the resistance of the third resistor R3 is 330Ω.
[0008] Preferably, in this technical solution, the resistance value of the second resistor R2 is 1KΩ, and the capacitance value of the first capacitor C1 is 1UF.
[0009] Preferably, in this technical solution, the resistance value of the second resistor R2 is 1KΩ, and the capacitance value of the first capacitor C1 is 0.1UF.
[0010] Preferably, in this technical solution, the resistance of the second resistor R2 is 1KΩ, and the capacitance of the first capacitor C1 is 0.22UF.
[0011] Compared with the prior art, the present invention has the following beneficial effects:
[0012] The utility model delays the switching state of the transistor by different time periods, so that the indicator light LED1 can clearly show flashing when the amount of data is small or the transmission time interval is long. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 This is the circuit schematic diagram of the utility model;
[0014] Figure 2 This is a schematic diagram of an embodiment of the present invention. DETAILED DESCRIPTION
[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0016] See also Figure 1 A circuit for controlling an indicator light for receiving and transmitting data via a serial port includes an indicator light LED1, wherein an anode of the indicator light LED1 is connected to a power supply VCC, a cathode of the indicator light LED1 is connected to one end of a third resistor R3, the other end of the third resistor R3 is connected to an emitter of a second transistor Q2, and a collector of the second transistor Q2 is grounded;
[0017] The base set of the second transistor Q2 is connected to one end of the second resistor R2, the other end of the second resistor R2 is commonly connected to one end of the first capacitor C1 and the emitter of the first transistor Q1, and the other end of the first capacitor C1 is grounded; the collector of the first transistor Q1 is grounded, the base set of the first transistor Q1 is connected to one end of the first resistor R1, and the other end of the first resistor R1 is connected to the transmit / receive pin TX / RX of the chip.
[0018] Working principle description:
[0019] When the serial port is idle, the serial port line is at a high level (ie, the transmit and receive pins TX / RX are at a high level), the first transistor Q1 and the second transistor Q2 are both in the cut-off state, and the indicator LED1 is off.
[0020] When the serial port sends data, the signal is a high-low pulse waveform. The first transistor Q1 and the second transistor Q2 are both in the off state, and the indicator LED1 is off. When the signal is low, the first transistor Q1 is turned on, the upper end of the first capacitor C1 is grounded through the first transistor Q1 to a low level, the base of the second transistor Q2 is low, the second transistor Q2 is turned on, and the indicator LED1 is lit. When the serial port jumps to high, the first transistor Q1 is turned off, and the first capacitor C1 is charged through the second transistor Q2 (emitter set E - base set B) and the second resistor R2. Due to the impedance of the second resistor R2, the charging time of the first capacitor C1 is slow. Therefore, the base of the second transistor Q2 can continue to remain on for a period of time while the first capacitor C1 is charging, thereby extending the lighting time of the indicator LED1. Even when the interval between data transmission is larger, the flashing indication can be clear.
[0021] For more specific working principles, please refer to the following Example 1
[0022] Example 1
[0023] See Figure 2 Preferably, the resistance of the first resistor R1 is 1KΩ, the resistance of the second resistor R2 is 1KΩ, the resistance of the third resistor R3 is 330Ω, the model of the first transistor Q1 is PMBT3906, the model of the second transistor Q2 is PMBT3906, and the power supply VCC is 3.3V.
[0024] The lighting time of the indicator LED1 is affected by the second resistor R2 and the first capacitor C1. Therefore, changing the values of the second resistor R2 and the first capacitor C1 can change the lighting time of the indicator LED1. Specifically:
[0025] The calculation formula of the time constant τ is τ=RC, where R is the resistance value and C is the capacitance value.
[0026] According to the formula τ=RC, if the second resistor R2=1KΩ, the first capacitor C1=1UF, the capacitor charge and discharge time τ=1000x0.001F=1 second;
[0027] If the second resistor R2 = 1KΩ, the first capacitor C1 = 0.1UF, the capacitor charging and discharging time T = 10000x0.001 = 0.1 seconds;
[0028] If the second resistor R2 = 1KΩ, the first capacitor C1 = 0.22UF, the capacitor charge and discharge time T = 1000x0.00022F = 0.22 seconds;
[0029] As shown above, based on the RC circuit's time constant: τ = RC, increasing the second resistor R2 or the first capacitor C1 can cause the indicator LED1 to illuminate longer, making it appear brighter. This constant measures the speed of voltage or current transitions in a circuit. In an RC circuit, this time constant reflects the speed at which the capacitor charges or discharges, with a longer time constant indicating a slower charging or discharging process, while a shorter time constant indicates a faster charging or discharging process. Therefore, this circuit can use the RC circuit to delay the switching state of the transistor to adapt to the waveform of the serial port data transmission and reception, ensuring clear indicator light indication at different baud rates and data volumes.
[0030] The specifications and models of the various electrical components in the present invention are not limited to those in the first embodiment.
[0031] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.
[0032] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A circuit for controlling an indicator light by sending and receiving serial port data, characterized in that: It includes an indicator light LED1, wherein the anode of the indicator light LED1 is connected to the power supply VCC, the cathode of the indicator light LED1 is connected to one end of a third resistor R3, the other end of the third resistor R3 is connected to the emitter of a second transistor Q2, and the collector of the second transistor Q2 is grounded; The base set of the second transistor Q2 is connected to one end of the second resistor R2, the other end of the second resistor R2 is commonly connected to one end of the first capacitor C1 and the emitter of the first transistor Q1, and the other end of the first capacitor C1 is grounded; the collector of the first transistor Q1 is grounded, the base set of the first transistor Q1 is connected to one end of the first resistor R1, and the other end of the first resistor R1 is connected to the transmit / receive pin TX / RX of the chip.
2. The circuit for controlling an indicator light by transmitting and receiving serial data according to claim 1, characterized in that: The first transistor Q1 is PMBT3906; The second transistor Q2 is PMBT3906.
3. The circuit for controlling an indicator light by transmitting and receiving serial data according to claim 2, characterized in that: The resistance of the first resistor R1 is 1KΩ, and the resistance of the third resistor R3 is 330Ω.
4. The circuit for controlling an indicator light by transmitting and receiving serial data according to claim 3, characterized in that: The resistance of the second resistor R2 is 1KΩ, and the capacitance of the first capacitor C1 is 1UF.
5. The circuit for controlling an indicator light by transmitting and receiving serial data according to claim 3, characterized in that: The resistance of the second resistor R2 is 1KΩ, and the capacitance of the first capacitor C1 is 0.1UF.
6. The circuit for controlling an indicator light by transmitting and receiving serial data according to claim 3, characterized in that: The resistance of the second resistor R2 is 1KΩ, and the capacitance of the first capacitor C1 is 0.22UF.