; U11
; PIN Declarations related to address decoding

pin	2	 E
pin	3	 A15
pin	4	 A14
pin	5	 A11
pin	6	 A0
pin	7	 A13
pin	8	 RW
pin	9	 A10

pin	12	 PORTB
pin	13	 OE
pin	14	 RWRAM
pin	17	 LCD
pin	19	 PORTC 

EQUATIONS for U11
; A12 is not used because there are not enough inputs on U11.
; It results a partial decodeing on the address ranges of PORTB and PORTC. 
; The address range $1400-$17FF is duplicated 
; at $0400-$07FF, but it does not conflict with any other memory devices.

; The addresses for portB, portC and LCD are partial decoded as well 
; since A1-A9 are not used. Actually portC and LCD
; share the same address, but former is for reading and latter is for writing.


;Logic equations related to address decoding:
; read  $1403 (U9, 74HC245, being used as a 74HC244)
/PORTC = /A15 * /A14 * /A13 * /A11 * A10 * A0 * E * RW ;

; write 1401 (U1, 74HC273)
/LCD   = /A15 * /A14 * /A13 * /A11 * A10 * A0 * E * /RW ;

; write 1404 (U10, 74HC273)
/PORTB = /A15 * /A14 * /A13 * /A11 * A10 * /A0 * E * /RW ;

/OE = E * RW ;
/RWRAM = E * /RW ;