I have connected LTDC output to VGA monitor input and the picture is flickering. I've connected HSYNC and VSYNC signals, ground pin and only the highest R/G/B bits over 500 Ohm resistors to R/G/B input signals of the monitor. I've set vertical/horizontal settings according to the VGA timings (pixels, front+back porch, sync) and layer 0 window height/width and frame buffer address to Bank 1 (0x24000000). I get expected result, which are random pixels, since I have not initialized memory. The problem is that the picture on the monitor is not stable. I did something similar some time ago with 8-bit MCU and I got similar flicker when the frequency was not exact (within 0.5%), but when I connected an exact CMOS clock, the flickering stopped.
So, I tried different combinations os HSI, on-board HSE CMOS and RC oscillator, VGA signalling for 640x480 and 800x600, no improvement. The image is still flickering.
Am I missing something? Or on-board 8Mhz oscillator is not within 0.5% tollerance? It says that on-chip oscillator has 1% tolerance so that would explain at least that.
BTW, I tried it on two different monitors and there is flicker on both, slightly less on one of them.
