When I update my graphic LCD, I have done an cli() and sei() before and after. This does not affect SPI or i2c protocols nor are they affected by ISR's.
Problem is I now want a PWM signal to control an RGB LED and cli() obviously affects this.
So there is either some LCD corruption or LED flicker and I can't find a solution for both.
It looks to me that this can't be done or can someone point me in the right direction.