LuatOS-Soc驱动WS2812教程

前言

很久没写东西了，马上520了，程序猿和攻城狮们，给女朋友点个灯表白吧~（没有女朋友？男朋友也可以嘛~）

介绍

ws2812是一款比较常用的外控集成LED光源，具有低电压驱动、环保节能、亮度高、散射角度大、低功率及超长寿命等优点。控制简单，应用领域极广。

驱动ws2812需要条件如下:

显然，不是所有mcu都能支持的，所以LuatOS-Soc在支持gpio直驱的情况下加入了PWM和SPI驱动的方法：

sensor.ws2812b_pwm(pin,data)和sensor.ws2812b_spi(pin,data)

下面看看这两个函数对硬件要求:

sensor.ws2812b_pwm(pin,data)：800k的PWM输出频率

sensor.ws2812b_spi(pin,data)：5Mbps 的SPI输出速率

显然，这要求就很低了，三种驱动方式，总有一款适合你~

Air101/Air103:推荐使用spi驱动方式

Air105:推荐使用pwm驱动方式，也可使用spi驱动方式，io直驱也可但实际有点勉强

使用

首先看一下api说明：

是不是api很简单？配合zbuff更简单，下面我们就显示❤+520

首先将我们要显示的换算成GBR颜色数组：

local show_520 = {
    {0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff},
    {0x0000ff,0x00ff00,0x00ff00,0x0000ff,0x0000ff,0x00ff00,0x00ff00,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff},
    {0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x0000ff,0x00ff00,0x00ff00,0x00ff00,0x0000ff,0x00ff00,0x00ff00,0x00ff00,0x0000ff,0x00ff00,0x00ff00,0x00ff00,0x0000ff,0x0000ff,0x0000ff,0x0000ff},
    {0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x0000ff,0x00ff00,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x00ff00,0x0000ff,0x00ff00,0x0000ff,0x00ff00,0x0000ff,0x0000ff,0x0000ff,0x0000ff},
    {0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x0000ff,0x00ff00,0x00ff00,0x00ff00,0x0000ff,0x00ff00,0x00ff00,0x00ff00,0x0000ff,0x00ff00,0x0000ff,0x00ff00,0x0000ff,0x0000ff,0x0000ff,0x0000ff},
    {0x0000ff,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x00ff00,0x0000ff,0x00ff00,0x0000ff,0x0000ff,0x0000ff,0x00ff00,0x0000ff,0x00ff00,0x0000ff,0x0000ff,0x0000ff,0x0000ff},
    {0x0000ff,0x0000ff,0x00ff00,0x00ff00,0x00ff00,0x00ff00,0x0000ff,0x0000ff,0x0000ff,0x00ff00,0x00ff00,0x00ff00,0x0000ff,0x00ff00,0x00ff00,0x00ff00,0x0000ff,0x00ff00,0x00ff00,0x00ff00,0x0000ff,0x0000ff,0x0000ff,0x0000ff},
    {0x0000ff,0x0000ff,0x0000ff,0x00ff00,0x00ff00,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff,0x0000ff},
}
local show_520_w = 24
local show_520_h = 8

之后申请一个8*8的zbuff空间

local ws2812_w = 8
local ws2812_h = 8
local buff = zbuff.create({ws2812_w,ws2812_h,24},0x000000)

然后做一个简单的滚动显示函数就可以了

local function ws2812_roll_show(show_data,data_w)
    local m = 0
    while 1 do
        for j=0,ws2812_w-1 do
            if j%2==0 then
                for i=ws2812_w-1,0,-1 do
                    if m+ws2812_w-i>data_w then
                        buff:pixel(i,j,show_data[j+1][m+ws2812_w-i-data_w])
                    else
                        buff:pixel(i,j,show_data[j+1][m+ws2812_w-i])
                    end
                end
            else
                for i=0,ws2812_w-1 do
                    if m+i+1>data_w then
                        buff:pixel(i,j,show_data[j+1][m+i+1-data_w])
                    else
                        buff:pixel(i,j,show_data[j+1][m+i+1])
                    end
                end
            end
        end
        m = m+1
        if m==data_w then m=0 end
        sensor.ws2812b_pwm(5,buff)--此处使用pwm方法驱动,当然也可以用gpio,spi方式,API详情查看wiki https://wiki.luatos.com/api/sensor.html
        -- sensor.ws2812b_spi(0,buff)
        sys.wait(300)
    end
end

好，我们的表白程序写好了

看一下效果：

资料连接

demo