Snowflake Lights

A snowflake lamp based on HK32F030MJ4M6

Overview

This document contains

• Hardware introduction
• Firmware introduction
• Introduction to the host computer

introduce

Snowflake lamp using HK32F030MJ4M6 as the main control

Precautions

The TYPE-C female port of this product will interfere with snowflakes. When welding, it can be tilted upward to avoid the situation where thicker TYPE-C data cables cannot be connected.

I think the currently used TYPE-C female socket is more cost-effective, and the upturned welding is also an acceptable solution. I haven't found a female socket that better meets the requirements in the Lichuang Mall. Of course, if you have any better suggestions, please feel free to put them in the comment area

There are certain differences in signal timing between the WS2812 used in this project and the WS2812 sold in the mall:

WS2812 sold in the mall:

It can be seen that after receiving 24-bit data, this WS2812 will interpret it as green, red, and blue (GRB) in sequence .

The WS2812 used in this project will interpret 24-bit data into red, green, and blue (RGB) at one time .

Of course, there may be other situations in WS2812 sold on the market. If your WS2812 does not interpret data in RGB order, please modify the firmware code to adapt to your hardware.

Line 338 of the firmwaresrcmain.c file defines a function void SN_WS2812_Transmit(uint8_t* color), which is a data sending function. This function will be called every time the color information is updated. The passed-in parameter color is a color array, with 3 adjacent data as a group, namely R, G and B values.

You can modify lines 344 ~ 346 of this file, which are lines 6 ~ 8 in this function. The original code is

R = (uint8_t)(color[3 * pos] * LED_light);
G = (uint8_t)(color[3 * pos + 1] * LED_light);
B = (uint8_t)(color[3 * pos + 2] * LED_light);

Among them, the corresponding relationship between RGB and digits is as follows:

That is, if you are using WS2812 to interpret data according to GRB, you should modify the code to:

G = (uint8_t)(color[3 * pos] * LED_light);
R = (uint8_t)(color[3 * pos + 1] * LED_light);
B = (uint8_t)(color[3 * pos + 2] * LED_light);

Here I directly modified the previous variable name, of course you can also modify the subsequent value.

Manufacturing steps

1. Use snowflake-lights/hardware/Gerber.zip for pattern making
2. Purchase the device and solder it, please pay attention when soldering
   • Complete the welding of all WS2812 lamp beads first , and then weld the decoupling capacitor to prevent the decoupling capacitor from hindering the lamp bead welding.
   • Upturned TYPE-C female seat .
3. Test and power on

Project details

The following link directs to the Gitee project address, where you can view code updates in real time

Snowflake Lights Hardware

introduce

The following content contains an introduction to schematics, PCB, and GERBER

MCU pin distribution

MCU pin function mapping

Main bill of materials

Model rendering

top	bottom

Snowflake Lights Firmware

introduce

The following content contains an introduction to the EWARM project

MCU pin function mapping

Peripheral configuration information

• SPI

  Setting items	content	Remark
  SPI_Direction	SPI_Direction_1Line_Tx	Single line sending
  SPI_Mode	SPI_Mode_Master	host mode
  SPI_DataSize	SPI_DataSize_10b	10 Bits
  SPI_CPOL	SPI_CPOL_Low	Low level idle
  SPI_CPHA	SPI_CPHA_2Edge	Second edge sampling
  SPI_BaudRatePrescaler	SPI_BaudRatePrescaler_4	4 dividers
  SPI_FirstBit	SPI_FirstBit_MSB	High starting position

• USART

  Setting items	content	Remark
  USART_BaudRate	115200	baud rate
  USART_HardwareFlowControl_None	USART_HardwareFlowControl_None	Does not use hardware flow control
  USART_Mode	USART_Mode_Tx|USART_Mode_Rx	Use TX RX at the same time
  USART_Parity	USART_Parity_No	No parity bit
  USART_StopBits	USART_StopBits_1	Stop bit
  USART_WordLength	USART_WordLength_8b	Data bit length

Secondary development

• Pin 7

  • Used as reset button by default .
  • It can be reused as an external interrupt , and the falling edge triggers the interrupt.
  • Can be reused as GPIO input mode , and loop to determine whether it is low level.

• Pin 8

  • Used as SWDIO by default
  • Can be reused as USART1-TX . At this time, SW cannot be used to debug , but it can be downloaded through SW.

Precautions

Since SWDIO will be reused as TX and NRST as external interrupt immediately after power-on, if you need to program the code again, please follow the steps below.

1. Power off the device.
2. Keep the button pressed and power up.
3. Continue to keep the button pressed and use the debugger to connect the computer to the device.
4. Continue to keep the button pressed to start the download process.
5. Continue to keep the button pressed , and release the button when the word Flashing appears on the screen .

Snowflake Lights Software

introduce

The following content contains the upper computer code introduction

The host computer is developed using python3 and uses the serial port to communicate with the snowflake lamp. The baud rate is fixed at 115200. Of course, the user can also directly modify the code to change the baud rate.

Window screenshot

Configuration file

Directory Structure

• The configuration file needs to be placed in the styles folder under the installation directory.
• The folder should contain a db.csv data file
• It is recommended to place all image files used in the styles directory and its subdirectories

db.csv file format

• The prompt text will be displayed in the drop-down list. Since the component width is fixed, please modify the prompt text and run the program to see whether the prompt text can be fully displayed in the list box.
• It is recommended to use letters and numbers as identification codes to avoid garbled characters during text encoding and decoding.
• Please fill in the relative path in column 3 to specify the display image or animation. The path is relative to the styles directory and supports ./ ../ symbols, but it is not recommended to place images and animation files outside the styles directory.
• Display pictures support common image formats, and display animations only support gif format.
• If column 3 is left blank, the content filled in column 1 will be displayed in the display area.

Default db.csv file content

letter of agreement

• The upper computer and lower computer should send requests at least 5ms apart from the last request sent by the local computer .
• Unless otherwise specified, all characters and symbols used in this communication protocol should be in English half-width format.
• Unless otherwise specified, all characters below represent a newline character .characters represent a null character .
• Unless otherwise specified, all space characters below should not appear consecutively .
• Unless otherwise specified, all character strings specified in this communication protocol should end with symbols, and symbols are not used as a valid basis for judgment.

shake hands

1. The host computer sends the handshake request string sl connect query to the serial port.
2. After receiving the handshake request, the lower computer replies with the string sl connect successfully dev:"AAAAA" ver:"BBBBB" .
   • AAAAA should be replaced with the firmware developer name.
   • BBBBB should be replaced with the firmware version number.
3. After receiving the reply, the host computer displays the developer's name and firmware version number on the screen.

Change style

1. The host computer sends the style change request string sl code XXXXX to the serial port.
   • XXXXX should be replaced with the identifier corresponding to the style used .
   • It should be ensured that the identification codes of the upper computer and lower computer are consistent.
   • Modify the stylesdb.csv file to modify the corresponding relationship between the host computer identification codes.
   • If you want to modify the corresponding relationship between the identification codes of the lower computer, please modify the firmware code directly.
2. After receiving the style change request, the lower computer parses the identification code and immediately changes it to the corresponding style.

Identification code format

• reserved identification code
  • Monochrome display identification code
  • All upper computers and lower computers using this communication protocol should support this identification code.
  • Identification code format color RRR GGG BBB
  • Please replace RRR GGG BBB in the identification code with the color R, G, and B values ​​respectively.
  • It should be ensured that the color R, G, and B values ​​are integers in the range of 0 ~ 255 .
• open identifier
  • The open identification code is used to identify special styles and should be unified between the upper computer and the lower computer.
  • The open identification code should minimize the use of space symbols to avoid being recognized as a reserved identification code by the lower computer.
  • It is recommended to use a combination of letters and numbers without spaces as the open identification code.

Change brightness

1. The host computer sends the brightness change request string sl light XXXXX to the serial port.
   • XXXXX should be replaced with the brightness to be used.
   • Brightness should be a decimal in the range 0 - 1 .
2. After receiving the brightness change request, the lower computer parses the brightness value and immediately changes it to the specified brightness.
   • Display style should not be modified when modifying brightness.
   • This brightness setting should take effect for all current and future styles.
   • This brightness setting should expire on the next brightness change request. Bold