【LPC845月餅板】+ WS2812數(shù)字燈亮起來

LPC845月餅板上有12顆WS2812數(shù)字燈。下面說說如何把這個燈點亮呢。

首先簡單說明下WS2812燈，他是RGB 3種顏色，每種顏色8Bit，總共24Bit數(shù)據(jù)。每個Bit的0,1碼是按照高低電平占空比來確定的。這個網(wǎng)上資料很多，不過這個0,1碼的占空比大小有好幾種。

有的是0碼是：H：0.5us，L：2.0us；1碼是H：1.2us，L：1.3us。

有的是0碼是：H：0.3us，L：0.9us；1碼是H：0.6us，L：0.7us。速度比上面的快1倍。

還有其他的我就不多說了。

我就是實現(xiàn)的0碼是H：0.3us，L：0.9us；1碼是H：0.6us，L：0.7us，這一種情況的。驅(qū)動WS2812B常用的方式有SPI、PWM、UASRT、GPIO模擬PWM等方式。本次就是用的SPI模式。使用SPI的mosi引腳驅(qū)動WS2812。

根據(jù)WS2812的0，1碼的占空比確定SPI輸出數(shù)據(jù)，1字節(jié)8Bit。

WS_BIT1 0x7C 1碼是H：0.6us，L：0.7us

WS_BIT0 0x60 0碼是H：0.3us，L：0.9us

根據(jù)電路圖得到燈的驅(qū)動管腳，然后初始化GPIO和SPI。如下圖可以看到使用的管腳是PIO1_13。

GPIO和SPI初始化如下，參照上一期LCD屏的SPI初始化。

void drv_spi_gpio_init(void)
{
    CLOCK_EnableClock(kCLOCK_Iocon);
    CLOCK_EnableClock(kCLOCK_Gpio0);
    CLOCK_EnableClock(kCLOCK_Gpio1);
    
    CLOCK_EnableClock(kCLOCK_Spi0);
    CLOCK_EnableClock(kCLOCK_Spi1);
    
    CLOCK_Select(kSPI0_Clk_From_MainClk);
    CLOCK_Select(kSPI1_Clk_From_MainClk);
    
    RESET_PeripheralReset(kSPI0_RST_N_SHIFT_RSTn);
    RESET_PeripheralReset(kSPI1_RST_N_SHIFT_RSTn);

    gpio_pin_config_t SPILCD_IN_config = {
        .pinDirection = kGPIO_DigitalInput,
        .outputLogic = 1U,
    };
    gpio_pin_config_t SPILCD_IOH_config = {
        .pinDirection = kGPIO_DigitalOutput,
        .outputLogic = 1U,
    };
    gpio_pin_config_t SPILCD_IOL_config = {
        .pinDirection = kGPIO_DigitalOutput,
        .outputLogic = 0U,
    };
    /* Initialize GPIO functionality on pin */
    GPIO_PinInit(GPIO, 0, 7, &SPILCD_IOL_config);//LCD_BLK
    GPIO_PinInit(GPIO, 1, 6, &SPILCD_IOH_config);//LCD_DC
    GPIO_PinInit(GPIO, 1, 7, &SPILCD_IOH_config);//LCD_RST
    GPIO_PinInit(GPIO, 1,18, &SPILCD_IOH_config);//LCD_CS
    GPIO_PinInit(GPIO, 1,19, &SPILCD_IOH_config);//LCD_CLK
    GPIO_PinInit(GPIO, 0, 6, &SPILCD_IOH_config);//LCD_MOSI
    
    GPIO_PinInit(GPIO, 1,13, &SPILCD_IOH_config);//RGB_MOSI
    
    GPIO_PinInit(GPIO, 1,8, &SPILCD_IOH_config); //FLASH_CS
    GPIO_PinInit(GPIO, 1,9, &SPILCD_IN_config); //FLASH_MISO
    GPIO_PinInit(GPIO, 0,12, &SPILCD_IOH_config);//FLASH_CLK
    GPIO_PinInit(GPIO, 0,13, &SPILCD_IOH_config);//FLASH_MOSI
    
    const uint32_t spilcd_ioc = (/* Selects pull-up function */
                              IOCON_PIO_MODE_PULLUP |
                              /* Enable hysteresis */
                              IOCON_PIO_HYS_EN |
                              /* Input not invert */
                              IOCON_PIO_INV_DI |
                              /* Disables Open-drain function */
                              IOCON_PIO_OD_DI |
                              /* Bypass input filter */
                              IOCON_PIO_SMODE_BYPASS |
                              /* IOCONCLKDIV0 */
                              IOCON_PIO_CLKDIV0);
    IOCON_PinMuxSet(IOCON, IOCON_INDEX_PIO0_7,  spilcd_ioc);
    IOCON_PinMuxSet(IOCON, IOCON_INDEX_PIO1_6,  spilcd_ioc);
    IOCON_PinMuxSet(IOCON, IOCON_INDEX_PIO1_7,  spilcd_ioc);
    IOCON_PinMuxSet(IOCON, IOCON_INDEX_PIO1_18, spilcd_ioc);    
    
    /* Enables clock for switch matrix.: enable */
    const uint32_t SPI_LCD_CLK = (/* Selects pull-up function */
                                    IOCON_PIO_MODE_PULLUP |
                                    /* Enable hysteresis */
                                    IOCON_PIO_HYS_EN |
                                    /* Input not invert */
                                    IOCON_PIO_INV_DI |
                                    /* Disables Open-drain function */
                                    IOCON_PIO_OD_DI |
                                    /* Bypass input filter */
                                    IOCON_PIO_SMODE_BYPASS |
                                    /* IOCONCLKDIV0 */
                                    IOCON_PIO_CLKDIV0);
    IOCON_PinMuxSet(IOCON, IOCON_INDEX_PIO1_19, SPI_LCD_CLK);

    const uint32_t SPI_LCD_MOSI = (/* Selects pull-up function */
                                    IOCON_PIO_MODE_PULLUP |
                                    /* Enable hysteresis */
                                    IOCON_PIO_HYS_EN |
                                    /* Input not invert */
                                    IOCON_PIO_INV_DI |
                                    /* Disables Open-drain function */
                                    IOCON_PIO_OD_DI |
                                    /* Bypass input filter */
                                    IOCON_PIO_SMODE_BYPASS |
                                    /* IOCONCLKDIV0 */
                                    IOCON_PIO_CLKDIV0);
    IOCON_PinMuxSet(IOCON, IOCON_INDEX_PIO0_6, SPI_LCD_MOSI);
    
    IOCON_PinMuxSet(IOCON, IOCON_INDEX_PIO1_13, SPI_LCD_MOSI);  //RGB_IO=MOSI
    
    const uint32_t SPI_MISO = (/* Selects pull-up function */
                                    0 |
                                    /* Enable hysteresis */
                                    IOCON_PIO_HYS_EN |
                                    /* Input not invert */
                                    IOCON_PIO_INV_DI |
                                    /* Disables Open-drain function */
                                    IOCON_PIO_OD_DI |
                                    /* Bypass input filter */
                                    IOCON_PIO_SMODE_BYPASS |
                                    /* IOCONCLKDIV0 */
                                    IOCON_PIO_CLKDIV0);
    IOCON_PinMuxSet(IOCON, IOCON_INDEX_PIO1_9, SPI_MISO);   //f_miso

    IOCON_PinMuxSet(IOCON, IOCON_INDEX_PIO1_8,   spilcd_ioc);    //f_cs
    IOCON_PinMuxSet(IOCON, IOCON_INDEX_PIO0_12,  spilcd_ioc);   //f_clk
    IOCON_PinMuxSet(IOCON, IOCON_INDEX_PIO0_13,  spilcd_ioc);   //f_mosi
    
    CLOCK_EnableClock(kCLOCK_Swm);
    
    SWM_SetMovablePinSelect(SWM0, kSWM_SPI0_SCK,   kSWM_PortPin_P1_19);
    SWM_SetMovablePinSelect(SWM0, kSWM_SPI0_MOSI,  kSWM_PortPin_P0_6);
    
    SWM_SetMovablePinSelect(SWM0, kSWM_SPI1_MOSI,  kSWM_PortPin_P1_13);
    
    /* Disable clock for switch matrix. */
    CLOCK_DisableClock(kCLOCK_Swm);
    
    spi_master_config_t userConfig = {0};
    uint32_t srcFreq               = 0U;
    /* Note: The slave board using interrupt way, slave will spend more time to write data
     *       to TX register, to prevent TX data missing in slave, we will add some delay between
     *       frames and capture data at the second edge, this operation will make the slave
     *       has more time to prapare the data.
     */
    
    SPI_MasterGetDefaultConfig(&userConfig);
    userConfig.baudRate_Bps           = 30000000;
    userConfig.sselNumber             = kSPI_Ssel0Assert;
    userConfig.clockPolarity          = kSPI_ClockPolarityActiveHigh;
    userConfig.clockPhase             = kSPI_ClockPhaseFirstEdge;
    userConfig.direction              = kSPI_MsbFirst;
    userConfig.delayConfig.preDelay   = 0x0U;
    userConfig.delayConfig.postDelay  = 0x0U;
    userConfig.delayConfig.frameDelay = 0x0U;
    userConfig.delayConfig.transferDelay = 0x0U;
    srcFreq                           = CLOCK_GetFreq(kCLOCK_MainClk);
    SPI_MasterInit(SPI0, &userConfig, srcFreq);
    
    userConfig.baudRate_Bps           = 6000000;
    SPI_MasterInit(SPI1, &userConfig, srcFreq);

}




SPI_Type * spi_table[2]=
{
    SPI0,
    SPI1,
};

void spi_pre_h(void)
{
    CLOCK_EnableClock(kCLOCK_Swm);
    SWM_SetMovablePinSelect(SWM0, kSWM_SPI1_MISO,  kSWM_PortPin_P1_9);  //F_MISO
    SWM_SetMovablePinSelect(SWM0, kSWM_SPI1_MOSI,  kSWM_PortPin_P0_13); //F_MOSI
    SWM_SetMovablePinSelect(SWM0, kSWM_SPI1_SCK ,  kSWM_PortPin_P0_12); //F_CLK
    CLOCK_DisableClock(kCLOCK_Swm);
    SPI_MasterSetBaudRate(SPI1,30000000, CLOCK_GetFreq(kCLOCK_MainClk));
}

void spi_pre_l(void)
{
    CLOCK_EnableClock(kCLOCK_Swm);
    SWM_SetMovablePinSelect(SWM0, kSWM_SPI1_MOSI,  kSWM_PortPin_P1_13); //RGB_IO
    SWM_SetMovablePinSelect(SWM0, kSWM_SPI1_MISO,  0XFF);  //
    SWM_SetMovablePinSelect(SWM0, kSWM_SPI1_SCK ,  0XFF);  //
    CLOCK_DisableClock(kCLOCK_Swm);
    SPI_MasterSetBaudRate(SPI1,6000000, CLOCK_GetFreq(kCLOCK_MainClk));
}

ws2812驅(qū)動代碼如下：

#include "stdint.h"
#include "string.h"
#include "main.h"
#include "drv_ws2812.h"
#include "drv_spi.h"
/*******************************************************************************
 * Definitions
 ******************************************************************************/
#define WS_TRANSFER_SIZE   (WS2812_PIXELS*24)   // Transfer dataSize

#define WS_BIT              24
#define WS_BIT1             0x7C
#define WS_BIT0             0x60

/*******************************************************************************
 * Variables
 ******************************************************************************/
volatile uint8_t g_WS2812TxBuf[WS_TRANSFER_SIZE];   // WS2812 Strip transmit data buffer

typedef union WS2812_ARGB
{
    struct
    {
        uint8_t b;
        uint8_t g;
        uint8_t r;
        uint8_t a;
    }s_argb;
    uint32_t u32_rgba;
}WS2812_ARGB_U;

/*
 * @brief   WS2812_StripInit
 * @param   NULL
 * @return  NULL
 */
void WS2812_Init(void)
{
    spi_pre_l();
    WS2812_ClearData();
    WS2812_SendData();
}


/*
 * @brief   WS2812_PixelSetBuff
 * @param   n, LED num / c, color / brightness, brightness
 * @return  NULL
 */
void WS2812_PixelSetIndexColor(uint16_t n, uint32_t color)
{
    volatile WS2812_ARGB_U l_color;
    uint16_t c_temp;
    
    if(n < WS2812_PIXELS)
    {
        memset((void *)&g_WS2812TxBuf[n*WS_BIT], WS_BIT0, 24);
        l_color.u32_rgba = color;
        c_temp = l_color.s_argb.a + 1;
        l_color.s_argb.r = (l_color.s_argb.r * c_temp) >> 8;
        l_color.s_argb.g = (l_color.s_argb.g * c_temp) >> 8;
        l_color.s_argb.b = (l_color.s_argb.b * c_temp) >> 8;
        
        if( ((l_color.s_argb.g>>7)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+0] = WS_BIT1;
        if( ((l_color.s_argb.g>>6)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+1] = WS_BIT1;
        if( ((l_color.s_argb.g>>5)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+2] = WS_BIT1;
        if( ((l_color.s_argb.g>>4)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+3] = WS_BIT1;
        if( ((l_color.s_argb.g>>3)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+4] = WS_BIT1;
        if( ((l_color.s_argb.g>>2)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+5] = WS_BIT1;
        if( ((l_color.s_argb.g>>1)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+6] = WS_BIT1;
        if( ((l_color.s_argb.g>>0)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+7] = WS_BIT1;
        
        if( ((l_color.s_argb.r>>7)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+0] = WS_BIT1;
        if( ((l_color.s_argb.r>>6)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+1] = WS_BIT1;
        if( ((l_color.s_argb.r>>5)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+2] = WS_BIT1;
        if( ((l_color.s_argb.r>>4)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+3] = WS_BIT1;
        if( ((l_color.s_argb.r>>3)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+4] = WS_BIT1;
        if( ((l_color.s_argb.r>>2)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+5] = WS_BIT1;
        if( ((l_color.s_argb.r>>1)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+6] = WS_BIT1;
        if( ((l_color.s_argb.r>>0)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+7] = WS_BIT1;
        
        if( ((l_color.s_argb.b>>7)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+0] = WS_BIT1;
        if( ((l_color.s_argb.b>>6)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+1] = WS_BIT1;
        if( ((l_color.s_argb.b>>5)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+2] = WS_BIT1;
        if( ((l_color.s_argb.b>>4)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+3] = WS_BIT1;
        if( ((l_color.s_argb.b>>3)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+4] = WS_BIT1;
        if( ((l_color.s_argb.b>>2)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+5] = WS_BIT1;
        if( ((l_color.s_argb.b>>1)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+6] = WS_BIT1;
        if( ((l_color.s_argb.b>>0)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+7] = WS_BIT1;
    }
}

void WS2812_PixelSetIndexRGB(uint16_t n, uint8_t r, uint8_t g, uint8_t b)
{    
    if(n < WS2812_PIXELS)
    {
        memset((void *)&g_WS2812TxBuf[n*WS_BIT], WS_BIT0, 24);

        if( ((g>>7)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+0] = WS_BIT1;
        if( ((g>>6)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+1] = WS_BIT1;
        if( ((g>>5)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+2] = WS_BIT1;
        if( ((g>>4)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+3] = WS_BIT1;
        if( ((g>>3)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+4] = WS_BIT1;
        if( ((g>>2)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+5] = WS_BIT1;
        if( ((g>>1)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+6] = WS_BIT1;
        if( ((g>>0)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 0+7] = WS_BIT1;
        
        if( ((r>>7)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+0] = WS_BIT1;
        if( ((r>>6)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+1] = WS_BIT1;
        if( ((r>>5)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+2] = WS_BIT1;
        if( ((r>>4)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+3] = WS_BIT1;
        if( ((r>>3)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+4] = WS_BIT1;
        if( ((r>>2)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+5] = WS_BIT1;
        if( ((r>>1)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+6] = WS_BIT1;
        if( ((r>>0)&0x01))  g_WS2812TxBuf[n*WS_BIT+ 8+7] = WS_BIT1;
        
        if( ((b>>7)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+0] = WS_BIT1;
        if( ((b>>6)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+1] = WS_BIT1;
        if( ((b>>5)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+2] = WS_BIT1;
        if( ((b>>4)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+3] = WS_BIT1;
        if( ((b>>3)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+4] = WS_BIT1;
        if( ((b>>2)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+5] = WS_BIT1;
        if( ((b>>1)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+6] = WS_BIT1;
        if( ((b>>0)&0x01))  g_WS2812TxBuf[n*WS_BIT+16+7] = WS_BIT1;
    }
}
/*
 * @brief   strip_clear, clean-up LED strip display
 * @param   NULL
 * @return  NULL
 */
void WS2812_ClearData(void)
{
    memset((void *)&g_WS2812TxBuf[0], WS_BIT0, (WS_TRANSFER_SIZE));//
}

/*
 * @brief   color_dim dimme color
 * @param   color, number of LEDs
 * @return  dimmed color
 */
void WS2812_SendData(void)
{
    volatile uint32_t i;
    spi_pre_l();
    for(i=0; i<WS_TRANSFER_SIZE; i++)
    {
        spi_writebyte(1,g_WS2812TxBuf[i]);
    }
    spi_pre_h();
}

void WS2812_ShowRGB(uint8_t r,uint8_t g,uint8_t b)
{
        uint8_t         i;

        for(i=0; i<WS2812_PIXELS; i++)
        {
                WS2812_PixelSetIndexRGB(i, r,g,b);
        }
    WS2812_SendData();
}

void WS2812_ShowColor(uint32_t color)
{
        uint8_t         i;

        for(i=0; i<WS2812_PIXELS; i++)
        {
                WS2812_PixelSetIndexColor(i, color);
        }
    WS2812_SendData();
}

void WS2812_ShowBuff(uint8_t *buff)
{
        uint8_t i;
        uint8_t *pLedData = buff;

    for(i=0; i<WS2812_PIXELS; i++)
        {
                WS2812_PixelSetIndexRGB(i, pLedData[0],pLedData[1],pLedData[2]);
        pLedData += 3;
        }
    WS2812_SendData();
}

好了，下面就可以開始測試WS2812效果了。

寫了2種效果，一個時鐘模式，一個轉(zhuǎn)圈模式

uint8_t clock_color_level[8]=
{
    0x10,
    0x30,
    0x70,
    0xa0,
    0xff,
    0,0,0,
};

uint8_t _hour,_minute,_second;
void ws2812rgb_clock_fsm(fsm_pt_t *pt)
{
    static int i;
    WS2812_ARGB_U rgb;
    
    PT_BEGIN(pt);
    
    _hour = 5;
    _minute = 5;
    _second = 40;
    
    while(1)
    {
        for(i=0;i<12;i++)
        {
            if(_second/5 == i) rgb.s_argb.r = clock_color_level[_second%5];
            else    rgb.s_argb.r = 0;
            
            if(_minute/5 == i) rgb.s_argb.g = clock_color_level[_minute%5];
            else    rgb.s_argb.g = 0;
            
            if(_hour == i)    rgb.s_argb.b = 0xff;
            else rgb.s_argb.b = 0;
            rgb.s_argb.a = rgb_light;
            
            WS2812_PixelSetIndexColor(i,rgb.u32_rgba);
        }
        WS2812_SendData();
        
        PT_WAIT_TIME(pt,1000);  //延時1秒
        
        _second++;
        if(_second == 60)
        {
            _minute ++;
            _second = 0;
            if(_minute == 60)
            {
                _minute = 0;
                _hour ++;
                if(_hour == 12)
                {
                    _hour = 0;
                }
            }
        }
    }
    PT_END(pt);
}

void ws2812rgb_demo_fsm(fsm_pt_t *pt)
{
    static int i;
    
    PT_BEGIN(pt);
    while(1)
    {
        for(i=0;i<12;i++)
        {
            WS2812_PixelSetIndexColor(i,WS2812_RED|(rgb_light<<24));
            WS2812_SendData();
            PT_WAIT_TIME(pt,100);
        }
        for(i=0;i<12;i++)
        {
            WS2812_PixelSetIndexColor(i,WS2812_GREEN|(rgb_light<<24));
            WS2812_SendData();
            PT_WAIT_TIME(pt,100);
        }
        for(i=0;i<12;i++)
        {
            WS2812_PixelSetIndexColor(i,WS2812_BLUE|(rgb_light<<24));
            WS2812_SendData();
            PT_WAIT_TIME(pt,100);
        }
    }
    PT_END(pt);
}

main函數(shù)

int main(void)
{
    BOARD_InitBootClocks();
    SysTick_Config(SystemCoreClock / 1000U);
    init_cycle_counter(true);
    
    BOARD_InitBootPins();
    drv_gpio_init();
    BOARD_InitDebugConsole();
    
    drv_spi_gpio_init();
    drv_i2c_gpio_init();
    
    DbgConsole_Printf("LPC845 Mooncake Board Test!rn");
    
    spilcd_init();
    
    __cycleof__("lcd_fresh_time(n/30000=X ms):")
    {
        spilcd_fill(0,0,240,240,LCD_RED);
    }
    delay_ms(100);
    __cycleof__("lcd_fresh_time(n/30000=X ms):")
    {
        spilcd_fill(0,0,240,240,LCD_GREEN);
    }
    delay_ms(100);
    __cycleof__("lcd_fresh_time(n/30000=X ms):")
    {
        spilcd_fill(0,0,240,240,LCD_BLUE);
    }
    delay_ms(100);
    __cycleof__("show 40*40 picture time:")
    {
        spilcd_draw_bitmap(100,100,40,40,(uint8_t *)gImage_1);
    }
    delay_ms(100);
        
    rgb_light = 0xff;
    WS2812_Init();
        while(1)
        {
        keyscan_fsm(&pt_key_scan);

資料如下：

lpc845_mooncake.zip (15.77 MB)