Hardware:

Keyboard matrix is following:
Scan lines are PORTE[0..2] and PORTF[3..4] active low.
Inputs are PORTE[3..7]

PORTE:
7	6	5	4	3	
[vol]	[OK]	[<-]	[8]	[1]	PORTE[0]
	[->]	[C]	[7]	[6]	PORTE[1]
			[#]	[5]	PORTE[2]
	[^]	[0]	[4]	[3]	PORTF[3]
[VM]	[*]	[*]	[9]	[2]	PORTF[4]



