short register 0x63: values 0x81 .. 0x8F
	set DPI as 100 .. 1500


short register 0x51: set leds
	value: ab cd 00
	where a/b/c/d values are 1=off, 2=on, 3=flash
		a = lower led
		b = red led
		c = upper led
		d = middle led