SAMA5D4-EK LCDC: Adding a delay after enabling the LCD solves lots of start-up timing issues

This commit is contained in:
Gregory Nutt 2014-07-12 08:05:22 -06:00
parent 20493f1212
commit 30603b1021

View File

@ -1,7 +1,7 @@
/****************************************************************************
* arch/arm/src/sama5/sam_lcd.c
*
* Copyright (C) 2013 Gregory Nutt. All rights reserved.
* Copyright (C) 2013-2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* References:
@ -2973,6 +2973,18 @@ int up_fbinitialize(void)
sam_show_hcr();
#endif
#if defined(BOARD_LCDC_ENABLE_DELAY) && BOARD_LCDC_ENABLE_DELAY > 0
/* Delay a bit after enabling the LDC. I presume that a delay of a few
* frame times allows some unstable clocking to synchronize before we
* tart thrashing the framebuffer? But I am not sure why this is
* necessary and, in fact, is certainly not necessary in most LCDC
* configurations. Perhaps this delay would not be necessary if timings
* were more precise?
*/
usleep(BOARD_LCDC_ENABLE_DELAY);
#endif
/* Enable the backlight.
*
* REVISIT: Backlight level could be dynamically adjustable