STM32F4xx-WS2812B-lib is a very simple to use library which handles WS2812B programmable LEDs using STM32F4xx. Whole library is intend as simple as possible to use. It requires only one command for initialization and includes only one command for particular LED settings.
The library is based on DMA, which transfers LED colour data directly into ODR register of the GPIO. Half of the GPIO peripheral is used (pins 0 to 7). Data is bursted via DMA on TIM1 Update trigger. It is important for bit-rate period to be about 400 ns, as the WS2812B interface is time dependent. Data transfer is triggered by TIM2 with frequency of 100Hz. This provides possibility to alter LED settings at any time, even in the main program loop. You can change refresh rate frequency, but bare in mind that it should depend on how many LEDs are there in the longest strip. Minimum refresh period is 404ns*72*LED_COUNT_IN_SEGMENT+50us. Timers period and prescalers are calculated for 168MHz SystemCoreClock, you should alter this values in an appropriate way.
Provide longest strip length in ws2812b_conf.h
#define LED_COUNT_IN_SEGMENT 200
here you can also change an output port for your WS2812B strip. Code below shows how to initialize and use the library:
#include "ws2812b.h"
int main(void)
{
WS2812B_Init();
WS2812B_SetRGB(0, 0, 255, 0, 0);
WS2812B_SetRGB(0, 1, 0, 255, 0);
WS2812B_SetRGB(0, 2, 0, 0, 255);
while(1)
{
}
}
WS2812B_SetRGB is defined as:
void WS2812B_SetRGB(uint8_t ChannelNumber, uint16_t LEDNumber, uint8_t R, uint8_t G, uint8_t B);
which is pretty much self-explanatory.
- CMSIS DSP Library v1.4.4
- STM32F4xx_DSP_StdPeriph_Lib_V1.6.0
MIT