CN215499644U

CN215499644U - LED lighting structure based on I2C bus expansion chip

Info

Publication number: CN215499644U
Application number: CN202122003142.1U
Authority: CN
Inventors: 魏文辉; 霍光辉; 魏建功; 张锋
Original assignee: Tianjin Qingyuan Huayue Technology Co ltd
Current assignee: Tianjin Qingyuan Huayue Technology Co ltd
Priority date: 2021-08-24
Filing date: 2021-08-24
Publication date: 2022-01-11
Anticipated expiration: 2031-08-24

Abstract

The utility model discloses an LED lighting structure based on an I2C bus extension chip, which comprises a Micro Control Unit (MCU) and an I/O extension chip, wherein the MCU is connected with the I/O extension chip through an I2C bus, and the I/O extension chip is connected with an LED lamp bank. And 2 non-clock leads of the micro control unit MCU are simulated into an SCL line and an SDA line to be in communication connection with the I/O expansion chip. Use the NCA9555 chip as an example, only need 2 lines of SCL line and SDA line can expand even 16I/O ports, also can control 16 LED lamps, has greatly solved the insufficient problem of MCU pin, has avoided too much occupation pin simultaneously again, and the design of software simulation communication is supported in I2C communication in addition, can promote the flexibility of MCU pin.

Description

LED lighting structure based on I2C bus expansion chip

Technical Field

The utility model relates to the technical field of electronic information, in particular to an LED lighting structure based on an I2C bus expansion chip.

Background

With the development of electronic technology, various electronic products enter the electronic market, including the power industry in vigorous development. LED indicator lamps are often used in the power industry to display operating status, and LED lamps are often required to indicate all operating statuses in consideration of each operating status. Therefore, the number of LED lamps required for one power device is large, often dozens or even hundreds, and the number of pins required is correspondingly increased. However, the IO pins of the MCU (MicrocontrollerUnit) are limited, and many pins need to do other work, which results in insufficient pin count. Therefore, it is considered to expand some I/O ports to realize a lighting circuit of the LED.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide an LED lighting structure based on an I2C bus expansion chip, which aims to solve the problem that the number of MCU pins is not enough and improve the flexibility of the MCU pins.

To solve the above technical problem, an embodiment of the present invention provides the following solutions:

the LED lighting structure based on the I2C bus extension chip comprises a Micro Control Unit (MCU) and an I/O extension chip, wherein the MCU is connected with the I/O extension chip through an I2C bus, and the I/O extension chip is connected with an LED lamp bank.

Preferably, 2 non-clock leads of the MCU are simulated as SCL and SDA lines to communicatively connect with the I/O expansion chip.

Preferably, the MCU adopts an STM32 singlechip.

Preferably, the I/O expansion chip adopts an NCA9555 chip.

Preferably, the NCA9555 chip is a 16-pin CMOS device and can extend 16I/O ports to control 16 LED lamps.

Preferably, the device address of the NCA9555 chip is determined by pins A0, A1 and A2, and the MCU realizes the control of a plurality of NCA9555 chips by inquiring different device addresses.

The technical scheme provided by the embodiment of the utility model has the beneficial effects that at least:

in the embodiment of the utility model, the MCU is connected with the I/O expansion chip through the I2C bus to expand the ports, for example, an NCA9555 chip can expand and connect 16I/O ports only by 2 wires of an SCL wire and an SDA wire, namely, 16 LED lamps can be controlled, the problem of insufficient MCU pins is greatly solved, and meanwhile, the excessive pin occupation is avoided, in addition, the design of software simulation communication supported by I2C communication can improve the flexibility of the MCU pins.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic block diagram of an LED lighting structure based on an I2C bus expansion chip according to an embodiment of the present invention;

FIG. 2 is a logic diagram of the interior of a channel of the NCA9555 chip according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a hardware design based on NCA9555 according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiment of the utility model provides an LED lighting structure based on an I2C bus expansion chip, as shown in FIG. 1, the LED lighting structure comprises a micro control unit MCU and an I/O expansion chip, wherein the micro control unit MCU is connected with the I/O expansion chip through an I2C bus, and the I/O expansion chip is connected with an LED lamp bank to control an LED indicator lamp.

In a specific embodiment, the micro control unit MCU may adopt an STM32 single chip microcomputer, and the I/O expansion chip may adopt an NCA9555 chip. 2 non-clock lead wires of the micro control unit MCU are simulated into an SCL wire and an SDA wire to be in communication connection with the I/O expansion chip, so that the expansion of the port is realized.

Taking the NCA9555 chip as an example, the NCA9555 chip is a 16-pin CMOS device, and can extend 16I/O ports to control 16 LED lamps. The NCA9555 chip supports 3-bit address definition, so that chip addresses can be different, theoretically, 16 x 8 IO ports can be supported, the problem that MCU pins are not enough can be greatly solved, meanwhile, too many pins cannot be occupied, and the I2C communication supports the design of software simulation communication, so that the flexibility of the MCU pins can be improved.

In the embodiment of the utility model, the communication between the MCU and the NCA9555 is in an I2C communication mode, and 2 non-clock pins of the MCU are simulated into two lines of SCL and SDA which are in communication connection with the NCA 9555. The MCU judges what the current working state of the equipment is according to the received external information, and sends command data to the NCA9555 through the SDA and the SCL after corresponding analysis, and controls the output of the command data, thereby realizing the on and off of the corresponding LED lamp.

The working voltage of the NCA9555 chip supports 3.3V/5V, 8-bit general parallel input/output ports (GPIOs) in I2C application are provided, and the NCA9555 chip comprises an 8-bit configuration register (input or output selection), an 8-bit input register, an 8-bit output register and a polarity inversion (high level or low level operation effective) register. The system host controller activates the input or output of the port by writing the corresponding configuration bit of the I/O port. The logic diagram inside one channel of the NCA9555 chip is shown in fig. 2.

According to the I2C communication protocol, I2C devices on the same bus need to define different addresses, so that each device can be distinguished, the number of devices hung on the I2C bus is limited, theoretically, at most, the number of devices hung on the I2C is determined by the I2C address, 8-bit address, 1-bit broadcast address is subtracted, 7-bit address is obtained, 2^7 ^ 128 is obtained, but the address 0x00 is not used, that is, 127 addresses, so that 127 slave devices can be hung theoretically.

The NCA9555 chip realizes different I2C addresses by 3 hardware pins A0, A1 and A2, 8 devices are allowed to share one I2C bus at most, and the device address of each NCA9555 chip is unique. The micro control unit MCU realizes the control of a plurality of NCA9555 chips by inquiring different device addresses.

As shown in fig. 3, when a0, a1 and a2 of the first piece of NCA9555(U57) are connected to GND, the device address of the NCA9555 is 0x40, when a0 of the second piece of NCA9555(U57) is connected to 10K pull-up resistor, and when a1 and a2 are connected to GND, the device address of the NCA9555 is 0x 41. The STM32 single-chip microcomputer is used as a main control chip, the simulated SDA and SCL pins are connected with NCA9555, and control over 32 lamps can be realized by inquiring different device addresses.

In summary, in the embodiment of the utility model, the control of multiple LED lamps can be realized by using 2 pins simulated by the MCU, so as to solve the problem of insufficient pins in the prior art; meanwhile, the LAYOUT design of the PCB is very convenient, a large amount of design time can be saved, and the scheme has higher reliability through verification.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. The LED lighting structure based on the I2C bus extension chip is characterized by comprising a Micro Control Unit (MCU) and an I/O extension chip, wherein the MCU is connected with the I/O extension chip through an I2C bus, and the I/O extension chip is connected with an LED lamp bank.

2. The I2C bus expansion chip-based LED lighting structure of claim 1, wherein 2 non-clock leads of the MCU are simulated as an SCL line and an SDA line to be communicatively connected with the I/O expansion chip.

3. The LED lighting structure based on the I2C bus extension chip of claim 1, wherein the MCU adopts an STM32 single chip microcomputer.

4. The I2C bus expansion chip-based LED lighting structure of claim 1, wherein the I/O expansion chip is NCA9555 chip.

5. The LED lighting structure based on the I2C bus extension chip is characterized in that, the NCA9555 chip is a 16-pin CMOS device, and can extend 16I/O ports to control 16 LED lamps.

6. The I2C bus expansion chip-based LED lighting structure of claim 4, wherein the device address of the NCA9555 chip is determined by pins A0, A1 and A2, and the MCU realizes control of multiple NCA9555 chips by inquiring different device addresses.