; ***************************************
; * EAROM Read/Write Routine          
; * Written by Clay Cowgill
; * http://www.multigame.com
; *
; * NOTE: Revised October 9, 1999.
; ***************************************

wait:
        ldy     #h'ff
waitloop:
        dey
        bne     waitloop

        rts


; ***************************************
; * Write EAROM
; *
; * x = address
; * a = data

ea_write:
        sta     scratch
        lda     #h'00
        sta     h'6040
        jsr     wait
        sta     h'6000,x
        jsr     wait
        lda     #h'0e
        sta     h'6040
        jsr     wait

        lda     #h'00
        sta     h'6040
        jsr     wait
        lda     scratch
        sta     h'6000,x
        jsr     wait
        lda     #h'0c
        sta     h'6040
        jsr     wait

        lda     #h'00
        sta     h'6040

        rts

; ***************************************
; * READ EAROM
; *
; * x = address
; * a = returned data

ea_read:
        lda     #h'00
        sta     h'6040
        jsr     wait
        lda     #h'08
        sta     h'6040
        sta     h'6000,x
        lda     #h'09
        sta     h'6040
        nop
        lda     #h'08
        sta     h'6040
        lda     h'6050

        ldy     #h'00
        sty     h'6040
        jsr     wait
        sty     h'6040

        rts