STM32F469 datasheet(29/91 Pages) STMICROELECTRONICS

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LCD-TFT (LTDC) display controller description

3.4

Interrupts

The LTDC peripheral supports two global interrupts:

•

LTDC global interrupt.

•

LTDC global error interrupt.

Each global interrupt is connected to two LTDC interrupts (logically disjointed) that can be

masked separately through a specific register. Table 7 summarizes all of the related

interrupts and all the particular cases when each interrupt is generated.

3.5

Low-power modes

The STM32 power state has a direct effect on the LTDC peripheral. While in sleep mode,

the LTDC is not affected and it keeps driving graphical data to the screen. While in the

standby and the stop mode, the LTDC is disabled and no output is driven through its parallel

interface. Exiting the standby mode should be followed with the LTDC reconfiguration.

It is possible to drive a display panel in sleep mode while the CPU is stopped thanks to the

smart architecture embedded in the STM32 microcontrollers which allows all the peripherals

to be enabled even in sleep mode. This feature fits wearable applications where the low-

power consumption is a must.

The LTDC as an AHB master may continue fetching data from FMC_SDRAM or Quad-SPI

(when the memory-mapped mode is used) even after entering the MCU in SLEEP mode. A

line event or register reload interrupt can be generated to wake up the STM32 when a

defined line on the screen is reached or when the shadow reload occurs.

More information on reducing power consumption is available on Section 5.

Table 8 summarizes the LTDC's state versus the STM32's low-power modes.

Table 7. LTDC interrupts summary

NVIC

interrupt

Interrupt

event

Event flag bit

(LTDC_ISR

Enable bit

(LTDC_IER

Clear bit

(LTDC_ICR

Description

LTDC

GLOBAL

INTERRUPT

Line

LIF

LIE

CLIF

Generated when a

defined line on the

screen is reached

reload

RRIF

RRIE

CRRIF

Generated when the

shadow reload

occurs

LTDC

GLOBAL

ERROR

INTERRUPT

FIFO

underrun(1)

1. FIFO underrun interrupt is useful for determining the display size compatibility (see Section 4.2.2:

Checking display compatibility considering the memory bandwidth requirements).

FUIF

FUIE

CFUIF

Generated when a

pixel is requested

while the FIFO is

empty

Transfer

error

TERRIF

TERRIE

CTERRIF

Generated when bus

error occurs

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