library<\/a> and added segment splitting to it. The Arduino library that inspired me also has this capability, but it is implemented in a slightly different way.<\/p>\n\n\n\nOne of my assumptions was dynamically creating the appropriate array of segments. Thanks to this, if you want only one segment, only one \u201cobject\u201d of a segment is created in memory. The number of segments can be changed on the fly. The code ensures there are no memory leaks and the segment array scales on an ongoing basis. One segment occupies 56 bytes in memory and looks like this:<\/p>\n\n\n\n
typedef struct ws2812bfx_s\n{\n\tvolatile uint32_t ModeDelay; \/\/ Segment SW timer counter\n\n\tuint16_t IdStart; \/\/ Start segment point\n\tuint16_t IdStop; \/\/ End segment point\n\n\tuint8_t Running : 1; \/\/ Is sector running\n\tuint8_t ActualMode; \/\/ Sector mode setting\n\tuint8_t Reverse : 1; \/\/ Is reverted mode\n\tuint32_t CounterModeCall; \/\/ Numbers of calls\n\tuint32_t CounterModeStep; \/\/ Call step\n\n\tuint16_t Speed; \/\/ Segment speed\n\n\tuint32_t ModeColor[NUM_COLORS]; \/\/ Mode color 32 bit representation\n\tws2812b_color ModeColor_w[NUM_COLORS]; \/\/ Mode color struct representation\n\n\tuint8_t AuxParam; \/\/ Computing variable\n\tuint16_t AuxParam16b; \/\/ Computing variable\n\tuint8_t Cycle : 1; \/\/ Cycle variable\n\n\tvoid (*mModeCallback)(void); \/\/ Sector mode callback\n} ws2812bfx_s;<\/pre>\n\n\n\nI am aware that some parameters are redundant for certain modes. Fortunately, this is not a huge cost. I will optimize it in the future as needed.<\/p>\n\n\n\n
Library fundamentals<\/h2>\n\n\n\n
For proper operation, the library requires software timers<\/em> and a callback in the main loop.<\/p>\n\n\n\nvoid WS2812BFX_SysTickCallback(void);<\/pre>\n\n\n\nI place the SysTick callback in the predefined SysTick callback located in the HAL libraries. Since it is a weak<\/em> function, I conveniently put it in the fourth user code section of the main.c<\/em> file. This is similar to the previous version of the library.<\/p>\n\n\n\nvoid WS2812BFX_Callback(void);<\/pre>\n\n\n\nThe FX library callback function, similar to the previous version, handles invoking subsequent effects. It must be placed in the main loop.<\/p>\n\n\n\n
Creating segments<\/h3>\n\n\n\n
In the example, I split the entire strip into 3 segments. After initializing LED control, you need to call the effect initialization using the function<\/p>\n\n\n\n
FX_STATUS WS2812BFX_Init(uint8_t Segments);\n<\/pre>\n\n\n\nThis function sets up the array of structures responsible for segments. It takes as an argument the number of segments into which the strip will be divided. This function divides the strip into equal parts. The function can also add another segment while remembering the settings of all previous ones. Removing a segment causes the information about the last one to be irretrievably lost, while every new segment above the previous count has default settings and is paused \u2013 you need to start it. For convenient addition and removal of segments, you can use the prepared functions.<\/p>\n\n\n\n
FX_STATUS WS2812BFX_SegmentIncrease(void);\nFX_STATUS WS2812BFX_SegmentDecrease(void);\n<\/pre>\n\n\n\nSegment configuration<\/h3>\n\n\n\n
Alright, but I\u2019d like different lengths for these segments. I anticipated that with several convenient functions.<\/p>\n\n\n\n
FX_STATUS WS2812BFX_SegmentIncreaseEnd(uint8_t Segment);\nFX_STATUS WS2812BFX_SegmentDecreaseEnd(uint8_t Segment);\nFX_STATUS WS2812BFX_SegmentIncreaseStart(uint8_t Segment);\nFX_STATUS WS2812BFX_SegmentDecreaseStart(uint8_t Segment);\n<\/pre>\n\n\n\nAs the names suggest, with them we can move the first and last point within a segment. These operations are safe and do not allow two neighboring segments to overlap. Therefore, for example, to increase segment no. 1 at the end, you must first move the start of segment no. 2.<\/p>\n\n\n\n
There is one more, less safe function.<\/p>\n\n\n\n
FX_STATUS WS2812BFX_SetSegmentSize(uint8_t Segment, uint16_t Start, uint16_t Stop);<\/pre>\n\n\n\nIt no longer prevents segments from overlapping. I didn\u2019t implement guarding for a simple reason. Everyone may imagine shifting a neighboring segment differently. Because what should be done when the neighboring segment already has only one LED? Remove it or shorten another one? Or maybe shorten all segments evenly as you expand? I leave that to you, and with this function you can freely configure the lengths of individual effects.<\/p>\n\n\n\n
Setting colors<\/h3>\n\n\n\n
Each mode requires at least one color to operate. The maximum number of colors required by any mode is 3. Each has its own ID by which it can be referenced. A color can be set in four ways.<\/p>\n\n\n\n
void WS2812BFX_SetColorStruct(uint8_t id, ws2812b_color c);\nvoid WS2812BFX_SetColorRGB(uint8_t id, uint8_t r, uint8_t g, uint8_t b);\nvoid WS2812BFX_SetColorHSV(uint8_t id, uint16_t h, uint8_t s, uint8_t v);\nvoid WS2812BFX_SetColor(uint8_t id, uint32_t c);\n<\/pre>\n\n\n\nThe effect of calling any of the above functions is the same. Note <\/em><\/strong>\u2013<\/em> <\/em>these functions assign the color to temporary variables. To apply them to a specific segment, you must afterward call the function that starts the selected operating mode on the given segment.<\/p>\n\n\n\nOperations on modes<\/h3>\n\n\n\n
Changing the mode of individual segments seems to be the most important function in the operation of a WS2812B LED strip.<\/p>\n\n\n\n
FX_STATUS WS2812BFX_SetMode(uint8_t Segment, fx_mode Mode);\nFX_STATUS WS2812BFX_NextMode(uint8_t Segment);\nFX_STATUS WS2812BFX_PrevMode(uint8_t Segment);\nFX_STATUS WS2812BFX_SetReverse(uint8_t Segment, uint8_t Reverse);<\/pre>\n\n\n\nThe names, as usual, speak for themselves. You can set a specific mode for a selected segment or choose the next or previous mode. The functions do not allow you to go beyond the list of available modes.<\/p>\n\n\n\n
The last two functions concern setting the direction of the animation for some modes, either one way or the other.<\/p>\n\n\n\n
Besides changing modes, the library allows you to control the operation of a given segment.<\/p>\n\n\n\n
FX_STATUS WS2812BFX_Start(uint8_t Segment);\nFX_STATUS WS2812BFX_Stop(uint8_t Segment);\n<\/pre>\n\n\n\nThese functions start or stop the animation on the selected segment. At the moment of start, the mode\u2019s timers <\/em>are reset and the colors stored in the temporary color settings variables are assigned \u2013 the segment will run from the beginning rather than continue from the stop point.<\/p>\n\n\n\nAnimation speed<\/h3>\n\n\n\n
The animation speed for each segment is set separately using the functions below.<\/p>\n\n\n\n
FX_STATUS WS2812BFX_SetSpeed(uint8_t Segment, uint16_t Speed);\nFX_STATUS WS2812BFX_IncreaseSpeed(uint8_t Segment, uint16_t Speed);\nFX_STATUS WS2812BFX_DecreaseSpeed(uint8_t Segment, uint16_t Speed);\n<\/pre>\n\n\n\nThe value of Speed<\/em> in the first function is expressed in milliseconds between each step in a mode. The exceptions are two modes \u2013 FX_MODE_WHITE_TO_COLOR<\/em> and FX_MODE_BLACK_TO_COLOR<\/em> \u2013 for which this value is the time needed for the transition black\/white -> color -> black\/white, also expressed in milliseconds.<\/p>\n\n\n\nThe last two functions increase the already set speed in the segment by the value from the Speed<\/em> argument.<\/p>\n\n\n\nCollecting information about segments<\/h3>\n\n\n\n
For the purposes of external communication, e.g., via UART or USB, there is a need to remotely check the configuration of the entire strip controller.<\/p>\n\n\n\n
uint8_t WS2812BFX_GetSegmentsQuantity(void);\nFX_STATUS WS2812BFX_IsRunning(uint8_t Segment, uint8_t *Running);\nFX_STATUS WS2812BFX_GetMode(uint8_t Segment, fx_mode *Mode);\nFX_STATUS WS2812BFX_GetReverse(uint8_t Segment, uint8_t *Reverse);\nFX_STATUS WS2812BFX_GetSegmentSize(uint8_t Segment, uint16_t *Start, uint16_t *Stop);\nFX_STATUS WS2812BFX_GetSpeed(uint8_t Segment, uint16_t *Speed);\nFX_STATUS WS2812BFX_GetColorRGB(uint8_t id, uint8_t *r, uint8_t *g, uint8_t *b);\n<\/pre>\n\n\n\nAll these functions return the appropriate operating parameters of the strip and segments. They return them via the pointers provided in the arguments. As you can see, each function returns an FX_STATUS value. This is related to the successful execution of the function. FX_STATUS has two states.<\/p>\n\n\n\n
typedef enum {\n FX_OK = 0,\n FX_ERROR = 1\n} FX_STATUS;\n<\/pre>\n\n\n\nFX_ERROR, as is easy to guess, indicates an error. For example, it may be an out-of-range error. Such an error will occur when trying to read the mode of segment no. 7 while only 5 are active.<\/p>\n\n\n\n
Example<\/h2>\n\n\n\n
I recorded a video that showcases the operation of segments and their configuration. For this purpose, I implemented USB communication via a virtual COM port <\/em>and simple message parsing. Please don\u2019t pay attention to the correctness of the parsing because there are many ways to do it, and the one I implemented here is quite primitive.<\/p>\n\n\n\n
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