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Renesas GLCDC

Overview

Architectural overview of Renesas GLCDC

GLCDC is a multi-stage graphics output peripheral used in Renesas MCUs. It is designed to automatically generate timing and data signals for different LCD panels.

  • Supports LCD panels with RGB interface (up to 24 bits) and sync signals (HSYNC, VSYNC and Data Enable optional)

  • Supports various color formats for input graphics planes (RGB888, ARGB8888, RGB565, ARGB1555, ARGB4444, CLUT8, CLUT4, CLUT1)

  • Supports the Color Look-Up Table (CLUT) usage for input graphics planes (ARGB8888) with 512 words (32 bits/word)

  • Supports various color formats for output (RGB888, RGB666, RGB565, Serial RGB888)

  • Can input two graphics planes on top of the background plane and blend them on the screen

  • Generates a dot clock to the panel. The clock source is selectable from internal or external (LCD_EXTCLK)

  • Supports brightness adjustment, contrast adjustment, and gamma correction

  • Supports GLCDC interrupts to handle frame-buffer switching or underflow detection

Setting up a project and further integration with Renesas' ecosystem is described in detail on page Renesas.
Check out the following repositories for ready-to-use examples:

Prerequisites

  • This diver relies on code generated by e² studio. Missing the step while setting up the project will cause a compilation error.

  • Activate the diver by setting LV_USE_RENESAS_GLCDC to 1 in your "lv_conf.h".

Usage

There is no need to implement any platform-specific functions.

The following code demonstrates using the diver in LV_DISPLAY_RENDER_MODE_DIRECT mode.

lv_display_t * disp = lv_renesas_glcdc_direct_create();
lv_display_set_default(disp);

To use the driver in LV_DISPLAY_RENDER_MODE_PARTIAL mode, an extra buffer must be allocated, preferably in the fastest available memory region.

Buffer swapping can be activated by passing a second buffer of same size instead of the NULL argument.

static lv_color_t partial_draw_buf[DISPLAY_HSIZE_INPUT0 * DISPLAY_VSIZE_INPUT0 / 10] BSP_PLACE_IN_SECTION(".sdram") BSP_ALIGN_VARIABLE(1024);

lv_display_t * disp = lv_renesas_glcdc_partial_create(partial_draw_buf, NULL, sizeof(partial_draw_buf));
lv_display_set_default(disp);

Note

Partial mode can be activated via the macro in src/board_init.c file of the demo projects.

Screen rotation

Software based screen rotation is supported in partial mode. It uses the common API, no extra configuration is required:

lv_display_set_rotation(lv_display_get_default(), LV_DISP_ROTATION_90);
/* OR */
lv_display_set_rotation(lv_display_get_default(), LV_DISP_ROTATION_180);
/* OR */
lv_display_set_rotation(lv_display_get_default(), LV_DISP_ROTATION_270);

Make sure the heap is large enough, as a buffer with the same size as the partial buffer will be allocated.