STM32-ARGB-DMA

Fastest and simplest library for ARGB LEDs: WS28xx and SK68xx Series RGB or RGBW for STM32 Series.
Uses DMA Interrupts and PWM to control LED Strip

RU Description

RU Habr

Features:

• Can be used for addressable RGB and RGBW LED strips
• Uses double-buffer and half-ready DMA interrupts, so RAM consumption is small
• Uses standard neopixel’s 800/400 KHz protocol
• Supports RGB and HSV color models
• Timer frequency auto-calculation

Limitations

• Only supports APBx frequency >32 MHz. It’s timers’ limitations.

Lib settings

#define WS2812       // Family: {WS2811S, WS2811F, WS2812, SK6812}
// WS2811S — RGB, 400kHz;
// WS2811F — RGB, 800kHz;
// WS2812  — GRB, 800kHz;
// SK6812  — RGBW, 800kHz

#define NUM_PIXELS 5 // Pixel quantity

#define USE_GAMMA_CORRECTION 1 // Gamma-correction should fix red&green, try for yourself

#define TIM_NUM	   2  // Timer number
#define TIM_CH	   TIM_CHANNEL_2  // Timer's PWM channel
#define DMA_HANDLE hdma_tim2_ch2_ch4  // DMA Channel
#define DMA_SIZE_WORD     // DMA Memory Data Width: {.._BYTE, .._HWORD, .._WORD}
// DMA channel can be found in main.c / tim.c

Function reference (from .h file):

// API enum status
typedef enum ARGB_STATE {
    ARGB_BUSY = 0,      // DMA Transfer in progress
    ARGB_READY = 1,     // DMA Ready to transfer
    ARGB_OK = 2,        // Function execution success
    ARGB_PARAM_ERR = 3, // Error in input parameters
} ARGB_STATE;

void ARGB_Init(void);   // Initialization
void ARGB_Clear(void);  // Clear strip

void ARGB_SetBrightness(u8_t br); // Set global brightness

void ARGB_SetRGB(u16_t i, u8_t r, u8_t g, u8_t b);  // Set single LED by RGB
void ARGB_SetHSV(u16_t i, u8_t hue, u8_t sat, u8_t val); // Set single LED by HSV
void ARGB_SetWhite(u16_t i, u8_t w); // Set white component in LED (RGBW)

void ARGB_FillRGB(u8_t r, u8_t g, u8_t b); // Fill all strip with RGB color
void ARGB_FillHSV(u8_t hue, u8_t sat, u8_t val); // Fill all strip with HSV color
void ARGB_FillWhite(u8_t w); // Fill all strip's white component (RGBW)

ARGB_STATE ARGB_Ready(void); // Get DMA Ready state
ARGB_STATE ARGB_Show(void); // Push data to the strip

Connection

Instructions for use:

Also available in PDF (RU/EN)

• Use CubeMX to configure clocks and peripheral.
• Enable PWM Generation for your preferred timer channel.
• PWM Mode 1, OC Preload: Enable, Fast Mode: Disable, CH Polarity: High
• Enable DMA for your timer channel with “Memory To Peripheral” direction.
• Set DMA mode to Circular, Data Width to Word/Byte, Increment Address checkbox only for Memory.
• Set GPIO Speed to the Maximum, use Open Drain or Push Pull Mode - details in Troubleshooting.
• Save CubeMX .ioc file and generate code.
• Add library to your source destination and add #include in your code.
• In main.c file search for your DMA Handler

/* Private variables */
TIM_HandleTypeDef htim2;
DMA_HandleTypeDef hdma_tim2_ch2_ch4;  <-- THIS

• Add this handler in ARGB.h file in DMA HANDLE define.
• Set other defines with your settings.
• Now we’re ready to go!

TROUBLESHOOTING

• IF STRIP DOESN’T WORK

  • You should convert logic levels
    • In Push Pull GPIO Mode use SN74LVC Translator
    • In Open Drain GPIO Mode use 1K PullUp Resistor
  • Check HAL DMA Generation order. DMA_Init should be higher than TIM_Init

• COLOR NOISE

  • Use Logic Analyzer or Oscilloscope to measure the signal, or just play with values
    • Correct timer values in .c file 152 string
• ANY OTHER
  • Write an issue!

Suggestions

• Write an issue or use pull request

Special thanks

NarodStream, VFD

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