STM32F479 datasheet(65/91 Pages) STMICROELECTRONICS

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LTDC application examples

Figure 34. LCD-TFT connection in the STM32F746G-DISCO board

As shown in Figure 34, the display module is connected to the MCU through two different

pin categories:

•

LTDC interface pins:

–

24-bit RGB interface.

–

Timing signals: LCD_HSYNC, LCD_VSYNC, LCD_DE and LCD_CLK.

•

Other specific pins:

–

LCD_DISP to enable/disable display standby mode.

–

INT interrupt line: allows the touch sensor to generate interrupts.

–

I2C interface to control the touch sensor.

–

LCD_RST reset pin allowing to reset the LCD-TFT, it is connected to the global

MCU reset pin (NRST).

–

LCD_BL_A and LCD_BL_K pins for LED backlight control: the backlight is

controlled by the STLD40DPUR circuit.

Backlight Controller: the STLD40DPUR circuit described in Figure 35 is a boost converter

that operates from 3.0 V to 5.5 V. It can provide an output voltage as high as 37 V and can

drive up to ten white LEDs in series. Refer to the STLD40D datasheet for more information

on the backlight controller.

The high level on the LCD_BL_CTRL (PK3) signal lights the backlight on, while the low level

switches it off.

Note:

It is possible to change the display brightness (dim the backlight intensity) by applying a low-

frequency (1 to 10 kHz) PWM signal to the EN pin 7 of the STLD40D circuit. This action

needs a rework since there is no timer PWM output alternate function available on the PK3

pin, so user should remove the R81 resistance and connect another GPIO pin with the

PWM output alternate function.

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