40% Jiadalong low axis keyboard

### Features

1. Jiadalong hot-swappable dwarf axis
2.40% configuration
3. QMK firmware (support via)
4. stm32f103c8t6 main control
5.0807 packaged front-mounted ws2812RGB light
6. Install steel plate satellite axis on PCB (PCB can only Make it 1.6mm thick)

### Some instructions

###### (1)

![2812-1.png] ![2812-2.png] ![2812-3.png] From the 3 pictures above It can be seen that the high-level threshold of WS2812 for data input is generally 0.7 times the power supply voltage, which
is 3.5V at 5V, while the working voltage of the stm32f103 chip is 3.3V. I did not find the output high-level in the chip manual. threshold,
but it should not exceed 3.3V, so the work of WS2812 may not be stable enough (but I have not had any problems when using it in other places)
, so I connected diodes in series to the power supply of the first two RGB lights. , to reduce its power supply voltage, so that the input threshold of the RGB light falls within the output threshold of stm32.
(You can also create a level conversion circuit)

###### (2)

Because the axis seat of the Jiadalong dwarf axis is wider than the axis seat of the normal axis, when using the steel plate satellite axis installed on the PCB During the design, one side of the pad will be cut in half (as shown below)
! [Axle seat 1.png] In order to avoid this problem, the other two projects using Jiadalong dwarf axis seat on the open source platform The shaft body in the shaft is rotated 90 degrees to install
the [50% low-shaft hot-swappable keypad] from DaDa (https://oshwhub.com/nimrodlord/ada40)
[50% low-shaft hot-swappable keypad] from ythfjjh Keyboard](https://oshwhub.com/ythfjjh/zq50)
I previously made a small board to verify that the half-cut solder pad can still fix the axis seat normally. For the sake of overall beauty,
I did not rotate it. The shaft body in the middle of the satellite shaft is still installed in the original direction, and it has been verified that it can be used normally.
(The picture size is a bit large and was lost in the attachment)

### The first update (2023.07.05)

has updated the QMK version, added via support, and uploaded via in the attachment using volume compression. Installation package.

### The second update (2023.07.28)

elongates the pad of the RGB lamp and replaces the resistor in the 0402 package with the 0603 package to facilitate soldering with a soldering iron.
The location of the download interface has been slightly moved to make it more convenient to re-download the BootLoader after it is damaged.
Updated the firmware to enable all lighting effects and lifted the brightness limit.
Corrected the positioning plate opening so that the satellite axis can pass completely through the positioning plate.
Uploaded a 3D printed shell model.

##### Update plan

~~1.3D printed shell (a hull has been drawn now, but it has not been verified yet. It will be sent to the attachment after verification)~~~~
2.via support, my qmk version It is neither new nor old, which means it neither supports the old version of local via nor the latest version of web via. I will update qmk after a while and learn how to write the new via~~
3. OLED screen support, on the board An IIC interface has been introduced, and I will update it after I figure out how to program OLED and draw the corresponding expansion board and shell
~~4. I will add an explanation of some parts in the next update~~
~~5. Prepare to change it to a suitable one Soldering iron to solder PCB of RGB lamp beads~~