I've made a board with ATMEGA8 running at 8MHz and 11 WS2812B LEDS.
Because of a shortcut, i've had hard time making it work but i'm facing a problem i've never had before.
On cold start (capacitor uncharged or shortcut between vcc and gnd pins), the ATMEGA starts normally, it drives the LEDs stripe with 24 bits datas but NO LIGHT at all.
At this point, i put a small wire or a screw driver on RESET pin, then, the LED stripe goes ON.
I can do the same if i power the board with the programmer port and reset the chip (ExtremBurner read or write function).
On "HOT" startup (Caps charged), everything run normally.
I've tryed adding a delay on startup (_delay_ms(800);) and also the startup fuse setup (0, 4ms, 64ms with C4, D4, E4 at LFUSE).
Strange thing isn't it ?
If someone has a hint about this, it would be great.