CW32 Multifunctional Testing Pen

This project utilizes the CW32f030 chip, replicating the CW32 open-source project. Although the replication process was fraught with difficulties and many problems were encountered, it was finally completed at the last minute. I also learned a lot of new knowledge and encountered new problems in the process. Below, I will introduce my project and the problems I encountered.
I. PCB Design.
First, I personally felt that a two-layer board was too extreme. Secondly, I also felt that I might find it very difficult to design a two-layer board, so I changed the board to a four-layer board. Some difficult-to-handle traces and the flying leads used by Engineer He in the project were added to the inner layer one. I used the inner layer one as a signal layer. In this way, the flying leads were placed in the inner layer, making the entire board very beautiful and complete, which is what I wanted to see. Secondly, I used the inner layer two as a ground layer to lay copper for GND and AGND respectively. This involved using the method of splitting the inner power layer. Below, I will explain the method of splitting the inner power layer:

use the polyline tool, then rebuild the inner power layer, use shift+b to partition, and then click to set the net.
The image shown is a diagram of the internal electrical layers that I created.
Secondly, the width of my multi-function pen is also wider than that of the original project because I think that being faster would make it easier to draw on the board and also increase the rigidity of the board.
After modifying this as shown in the diagram,
the second step was to solve the problem.
Once all the soldering was complete, I was eager to start programming, but things weren't so simple. First, I encountered the problem that the programmer couldn't recognize the chip. Initially, I used the SW interface of a DAPlink (from Liangshanpai) to program the CW32. Because my DAPlink's power supply is 5V, I used a Type-C port to power the chip, but I still couldn't recognize it. I asked some fellow programmers, and they suggested it might be a link incompatibility issue. So I quickly bought an ST-Link to try programming with it. However, when the ST-Link arrived, I burned it out. After investigating, I discovered that the ST-Link wires cannot be crossed; this can easily damage the chip. Initially, I connected the power wires on one side and the signal wires on the other, causing the ST-Link to burn out. I was forced to buy another one. After the ST-Link arrived, the chip was recognized, but the program couldn't be downloaded to the CW32, as shown below.
This is the ST-Link wiring diagram. Pay attention! Do not cross-connect the wires. (Secondly, J-Link cannot download CW32; it seems to be unrecognized. I've tried it myself,
and it doesn't work.) This is the error. If this error occurs, it means you haven't cracked the Keil 5 ARM. You need to crack Keil first, and then compile the program. After cracking, there should be no errors, only warnings, but it won't affect the burning process. After burning, your multi-function pen will look like this. I thought that would be enough, but then another problem arose. After soldering, it wouldn't turn on at all. So I analyzed all the digital circuits, checking all the problems one by one, and finally found that the linear regulator was faulty. The input was 4V and the output was 0.3V, so I replaced the regulator, and it worked. The multi-function pen could also turn on correctly. However, I later found that there was a white line on the screen, indicating that the program hadn't been burned. So I adjusted it. If your screen also has a line, you can adjust it like I did. Please
modify the image below to match the original image, that is, change the original 24 to 26 and change X to X+1. I hope this helps.