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走马观花

Lichuang EDA customized 87-key mechanical keyboard

 
Overview
Table of contents

1. Introduction

2. Design focus

1. Communication method

2. Crystal oscillator circuit

3. Power circuit

4. Manual description

3. Circuit design and sample making

1. Circuit design

2. PCB proofing

3. Purchase of components

4. Principle description

1. Power supply

2. Main control circuit

3. Key circuit

5. Picture Appreciation

1. PCB3D preview

2. Physical picture

6. Video

 

1. Introduction

This project is an 87-key mechanical keyboard officially drawn         by Lichuang EDA based on HT82K629A as the main controller;

        HT82K629A is an excellent USB keyboard dedicated chip with simple application and few peripheral circuits. It can be used directly connected to the computer without downloading drivers and code control. Is the best choice for DIY keyboard!

2. Design focus

1. Communication method

        HT82K629A can support two communication methods: USB and PS2. It can be used normally by directly using the USB data cable. You can also add a Bluetooth chip and a serial port chip for wireless Bluetooth transmission (you are welcome to modify it if you are creative);

2. Crystal oscillator circuit

        In addition to the 6M crystal oscillator in the reference schematic diagram, the 12M crystal oscillator is also compatible (pay attention to the last line on the second page of the manual);

3. Power circuit

        The working voltage of this chip is 4.4V~5.5V. It can communicate and supply power directly with a USB data cable. It does not require a step-up and step-down circuit, which is really convenient!

4. Manual description

        The chip manual is 27 pages long. If you don’t want to conduct in-depth communication tests with the computer, you only need to look at the key value matrix table on page 20 and the circuit reference diagram on page 22. There are not too many other issues that need attention. You can refer to us of this circuit.

3. Circuit design and sample making

1. Circuit design

        Use Lichuang EDA to draw the circuit principle. Regarding the schematic library and package library, you can use the official package library or the user shared library (thank you to the user for providing a large number of different styles of button packages). When you draw the schematic diagram, you give priority to Lichuang. After the EDA basic library device , not only the style is unified, but also comes with a 3D model . Next, layout and design are carried out according to the dxf positioning board file (for detailed operations, you can watch our live broadcast replay, the link is below)

2. PCB proofing

        Which company is better at PCB proofing? For exporting Gerber, go to Jialichuang ! ! Jialichuang's 5 yuan proofing is simply a benefit to all mankind. Although this keyboard PCB file exceeds the scope of 5 yuan proofing, we still have coupons. There are many ways to obtain proofing coupons, such as participating in the open source platform's collection order, Sign-in gifts on the open source platform, proofing coupons given out during Lichuang EDA training, or rewards for users who give us constructive opinions or feedback . We fully support you who love to do things~

3. Purchase of components

        To buy devices, choose Lichuang Mall . There is absolutely nothing wrong with this choice. The devices on Lichuang Mall are all original and genuine and do not contain fake or shoddy products. No matter in terms of learning, preparing for competitions, participating in competitions, etc., a genuine chip can save us a lot of detours.
        Lichuang Mall, which delivers goods within four hours , has two major warehouses in Shenzhen and Jiangsu. The delivery is fast , you can choose the express delivery method, and it also has high-quality after-sales service. The most important thing is that Lichuang Mall has a lot of activities , and there are many more every month Brand coupons are just like giving away equipment ! ! There is also a big gift package for new user registration ! ! !
(PS: The Lichuang EDA account is shared between Lichuang Mall and Jialichuang)

4. Principle explanation (multi-picture warning)

1. Power supplyimage.png

        In the picture, C1 and C2 are two power supply filter capacitors. In addition, R1 is used as the current limiting resistor of LED1. When the power is on, the LED lights up (this is the power indicator light)

2. Main control circuit

image.png
        In the picture above, X1 is the crystal oscillator circuit, which can be directly connected to the crystal oscillator. The size can be 6M or 12M ; R4 and R5 are used as reset circuits, and R6/7/8 are used as USB circuits. LED2-digit case lock indicator, LED3 is the scroll lock indicator. Since the 87-key key does not have a small numeric key, a non-connection indicator is added to the Num pin of the numeric lock to indicate that this pin is not used.

3. Key circuit

image.png
        There are several small issues that need to be paid attention to in the button circuit. The first is that the direction of the diode is from the R direction to the C direction. If the button is connected reversely, the button will not be triggered. If you find that there is no response when pressing the button during the test, you can check whether the diode is Welded well (you can directly short-circuit to test the button function);
        In addition, the role of the diode here is to provide full-key overshoot and cannot be omitted.

5. Picture Appreciation

1. PCB3D preview

image.png
 
image.png

2. Physical picture

Lichuang keyboard three.png
 
image.png

6. Video

Live playback of the complete video: https://www.bilibili.com/video/BV1XZ4y1x7ix

Full video of soldering PCB: https://www.bilibili.com/video/BV1Y54y19797?from=search&seid=3334337676173120982

Everyone is welcome to like, follow and collect! ! Three consecutive support! !

The following are the highlights of the video, click the link above for the complete video:

 
参考设计图片
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Design Files
 
 
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All reference designs on this site are sourced from major semiconductor manufacturers or collected online for learning and research. The copyright belongs to the semiconductor manufacturer or the original author. If you believe that the reference design of this site infringes upon your relevant rights and interests, please send us a rights notice. As a neutral platform service provider, we will take measures to delete the relevant content in accordance with relevant laws after receiving the relevant notice from the rights holder. Please send relevant notifications to email: bbs_service@eeworld.com.cn.

It is your responsibility to test the circuit yourself and determine its suitability for you. EEWorld will not be liable for direct, indirect, special, incidental, consequential or punitive damages arising from any cause or anything connected to any reference design used.

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Update:2024-11-22 12:08:27
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