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U15 address decoder – Zilog eZ80F92 User Manual

Page 81

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eZ80F92 Development Kit
User Manual

Appendix A

UM013911-0607

77

//Flash enabled if this is

0

//wire nDIS_FL = (nFL_DIS) ? ~nEXP_EN : ~(nFL_DIS);

wire nDIS_FL = nFL_DIS & nEXP_EN; //if either of them is 0

Flash

//is disabled

assign nCS_EX = (nEX_FL_DIS) ? nEXP_EN : ~(nEX_FL_DIS);

assign nL_RD =

~((nmemen1==0)|(nmemen2==0)|(nmemen3==0)|(nmemen4==0)|(nEM_EN=

=0)|(nCS_EX==0));

assign nmemen4 = ~((nCS2==0)&({A7,A6,A5,A4,A3}==5'h17));

assign nmemen3 = ~((nCS2==0)&({A7,A6,A5,A4,A3}==5'h16));

assign nmemen2 = ~((nCS2==0)&({A7,A6,A5,A4,A3}==5'h15));

assign nmemen1 = ~((nCS2==0)&({A7,A6,A5,A4,A3}==5'h14));

assign nEM_EN =

~((nCS2==0)&({A7,A6,A5,A4,A3,A2,A1,A0}==8'h80));

endmodule

U15 Address Decoder

`define

anode

8'h00

`define

cathode

8'h01

`define

latch

8'h02

// FOR eZ80 Development Platform Rev B

// This PAL generates signals that control Expansion

// Module access, LED and Port A emulation

// This device is a GAL22LV10-5JC (5ns tpd) or

// equivalent with Package = 28 pin PLCC

//

//