m6809a.abl

来自「自己编写的GAL可编程逻辑电路的编译软件abel4的windows界面」· ABL 代码 · 共 32 行

module M6809A 
title '6809 memory decode
Jean Designer  Data I/O Corp Redmond WA'

                        m6809a  device  'P14L4';
        A15,A14,A13,A12,A11,A10 pin 1,2,3,4,5,6;
        ROM1,IO,ROM2,DRAM       pin 14,15,16,17;

        H,L,X   = 1,0,.X.;
        Address = [A15,A14,A13,A12, A11,A10,X,X, X,X,X,X, X,X,X,X];

equations
        !DRAM   = (Address <= ^hDFFF);

        !IO     = (Address >= ^hE000) & (Address <= ^hE7FF);

        !ROM2   = (Address >= ^hF000) & (Address <= ^hF7FF);

        !ROM1   = (Address >= ^hF800);

test_vectors 
             (Address -> [ROM1,ROM2,IO,DRAM])
              ^h0000  -> [  H,  H,  H,   L ];
              ^h4000  -> [  H,  H,  H,   L ];
              ^h8000  -> [  H,  H,  H,   L ];
              ^hC000  -> [  H,  H,  H,   L ];
              ^hE000  -> [  H,  H,  L,   H ];
              ^hE800  -> [  H,  H,  H,   H ];
              ^hF000  -> [  H,  L,  H,   H ];
              ^hF800  -> [  L,  H,  H,   H ];
end M6809A