Crank Storyboard工程显示异常解决

小恩GG · 发表于 2021-7-28 13:57:42

问题现象

客户正在开发的项目想使用Crank[1]做LCD GUI界面，所以使用MIMXRT1050开发板和SDK library提供的Crank工程做功能验证与评估，在此过程中，他们注意到显示屏(RK043FN02H-CT)最左上角的（0，0）像素点显示为白色或者绿色（如下图所示），并且这个现象在测试Coffee Machine和Home Controls工程时都有复现，但并未出现在LVGL和emWin相关的工程中，所以客户怀疑此现象与硬件无关，猜测与SDK library中的PXP驱动有关。

图 1

问题分析与解决

小编根据客户的描述复现了上述问题现象，并在经过如下测试步骤后，基本认同客户的猜测，认为问题与硬件设计无关，并在与AE team沟通后，确认问题现象确与PXP驱动相关，导致gr_generic_display_update（）函数更新LCD时，数组值有错码。

降低LCD的DCLK频率
采用更稳定的外置电源供电
在IAR、MCUXpresso都有复现问题现象

解决方式有两种（如下图所示），第一种为使能ping-pong模式的双buffer缓存机制，以空间换时间，交替将显示数据传给LCD，这样的话，可以舍弃PXP模块，第二种方法是在原有程序基础上，修改PXP驱动，代码修改量相对较小。

图 2

修改后代码如下所示，允许开发者可以通过宏 #define APP_USE_PXP x 自主选择上述两种解决方式的任何一种。

#define APP_USE_PXP 1
/*
* Configure the PXP block to handle the framebuffer transfer in hardware.
*
* We will assume 16bit RGB565 based framebuffer
* - The LCD peripheral is setup to use eLCDIF_Buffer[0]
* - Storyboard is configured to render single buffer, eLCDIF_Buffer[1]
* - The PXP will be configured to transfer from eLCDIF_Buffer[1] to eLCDIF_Buffer[0]
*/
static void APP_InitPxp(void)
{
PXP_Init(APP_PXP);
/* PS configure. */
const pxp_ps_buffer_config_t psBufferConfig = {
.pixelFormat = kPXP_PsPixelFormatRGB565,
.swapByte = false,
.bufferAddr = (uint32_t)eLCDIF_Buffer[1],
.bufferAddrU = 0U,
.bufferAddrV = 0U,
.pitchBytes = APP_IMG_WIDTH * APP_BPP,
};
PXP_SetProcessSurfaceBackGroundColor(APP_PXP, 0x1f);
PXP_SetProcessSurfaceBufferConfig(APP_PXP, &psBufferConfig);
PXP_SetProcessSurfacePosition(APP_PXP, 0, 0, APP_IMG_WIDTH, APP_IMG_HEIGHT);
/* Disable AS. */
PXP_SetAlphaSurfacePosition(APP_PXP, 0xFFFFU, 0xFFFFU, 0U, 0U);
/* Output config. */
outputBufferConfig.pixelFormat = kPXP_OutputPixelFormatRGB565;
outputBufferConfig.interlacedMode = kPXP_OutputProgressive;
outputBufferConfig.buffer0Addr = (uint32_t)eLCDIF_Buffer[0];
outputBufferConfig.buffer1Addr = 0U;
outputBufferConfig.pitchBytes = APP_IMG_WIDTH * APP_BPP;
outputBufferConfig.width = APP_IMG_WIDTH;
outputBufferConfig.height = APP_IMG_HEIGHT;
PXP_SetOutputBufferConfig(APP_PXP, &outputBufferConfig);
/* Disable CSC1, it is enabled by default. */
PXP_EnableCsc1(APP_PXP, false);
/* Process 16x16 pixel blocks - Note: make sure this is appropriate for the display geometry */
PXP_SetProcessBlockSize(APP_PXP, kPXP_BlockSize16);
}
int
gr_generic_display_init(gr_generic_display_info_t *info) {
BOARD_InitLcdifPixelClock();
/* enable backlight */
BOARD_InitLcd();
info->num_layers = 1;
info->layer_info = &main_layer;
#if APP_USE_PXP
main_layer.num_buffers = 1; // Single render buffer for Storyboard
main_layer.buffer[0] = (void *)eLCDIF_Buffer[1];
#else
main_layer.num_buffers = 2; // double (ping-pong) render buffers for Storyboard
main_layer.buffer[0] = (void *)eLCDIF_Buffer[0];
main_layer.buffer[1] = (void *)eLCDIF_Buffer[1];
#endif
main_layer.render_format = GR_RENDER_FMT_RGB565;
main_layer.width = (uint16_t)APP_IMG_WIDTH;;
main_layer.height = (uint16_t)APP_IMG_HEIGHT;
main_layer.stride = (uint16_t)(main_layer.width * GR_RENDER_FMT_BYTESPP(main_layer.render_format));
ELCDIF_RgbModeInit(APP_ELCDIF, &eLCDIF_rgbConfig);
#if APP_USE_PXP
/* configure PXP for hardware assisted framebuffer transfer */
APP_InitPxp();
#else
/* Enable interrupt LCDIF_IRQn request in the NVIC. */
EnableIRQ(LCDIF_IRQn);
/* Enable interrupts */
ELCDIF_EnableInterrupts(ELCDIF_PERIPHERAL, (kELCDIF_CurFrameDoneInterruptEnable | kELCDIF_TxFifoUnderflowInterruptEnable));
#endif
ELCDIF_SetNextBufferAddr(APP_ELCDIF, (uint32_t)eLCDIF_Buffer[0]);
ELCDIF_RgbModeStart(APP_ELCDIF);
return 0;
}
int
gr_generic_display_update(const gr_generic_display_info_t *info) {
#if APP_USE_PXP
/* invalidate cache on the buffer about to be being written to LCD by pxp*/
DCACHE_CleanInvalidateByRange((uint32_t)info->layer_info[0].buffer[info->layer_info[0].buffer_draw_index], APP_IMG_HEIGHT * APP_IMG_WIDTH * GR_RENDER_FMT_BYTESPP(info->layer_info[0].render_format) );
/* Start PXP. */
PXP_Start(APP_PXP);
/* Wait for process complete. */
while (!(kPXP_CompleteFlag & PXP_GetStatusFlags(APP_PXP))) {}
PXP_ClearStatusFlags(APP_PXP, kPXP_CompleteFlag);
#else
/* invalidate cache on the buffer about to be being written to LCD */
DCACHE_CleanInvalidateByRange((uint32_t)info->layer_info[0].buffer[info->layer_info[0].buffer_draw_index], APP_IMG_HEIGHT * APP_IMG_WIDTH * GR_RENDER_FMT_BYTESPP(info->layer_info[0].render_format) );
s_frame_done = false;
ELCDIF_SetNextBufferAddr(APP_ELCDIF, (uint32_t)info->layer_info[0].buffer[info->layer_info[0].buffer_draw_index]);
while(s_frame_done == false) {}
#endif
return 0;
}