I’ve a couple of related questions about eboot timings:
Are there any circumstances where the splash screen image is not output on the parallel RGB interface until after the configured dispondelay?
If you configure the eboot configblock to turn on various GPIO pins in both the gpio block and the splash screen block (via the BL_GPIO and DISP_GPIO settings), is there a fixed deterministic order that the GPIO pins will be enabled? Or are the different config block settings applied asynchronously?
The background to the query is we are looking at using a different TFT LCD display with our Colibri T20s, previously we used a display that had a parallel RGB input but we are looking at using a different display which has a LVDS input with a TI DS90C383 to do the signal conversion.
This all works fine apart from we get a very brief (a few tens of milliseconds) flash of a random colour before the splash screen is shown – the colour changes each time and fills the whole screen. We do not control the display’s enabled signal but have two signals that control the backlight and when the backlight is off the display cannot be seen.
We have tried the obvious things of setting the ss.bl_gpio and disp_gpio to control the backlight signals and varying the dispondelay (up to several seconds), but all that happens is the coloured flash and splash screen are displayed later - after the dispondelay period. We have also tried all the combinations of pins to bl_gpio/disp_gpio, and all eboot versions from v2.0 to v2.3, without any success, and have done various hardware scoping. We do use a custom splash screen and WinCE 7 image (but standard eboot), but the issue also happens if I just use the standard Toradex flash image (v2.3 loading using the .cfg file) with the splash screen configblock updated to match the display timings and bl_gpio/disp_gpio.
However, if we configure the backlight signals to be set by the gpio config block then we don’t get the coloured flash. This is making us wonder if we have somehow caused the splash screen to not be output to the parallel RGB output until the dispondelay period and if so whether a workaround might be that we can reliably rely on some of the gpio settings being applied at a reasonably constant point.