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/*信号定义：
clk： 时钟信号，本例中其频率值为1Hz；
decide： 电话局反馈回来的信号，代表话务种类，“01”表示市话，“10”表示 长话，“11”表示特话；
dispmoney： 用来显示卡内余额，其单位为角，这里假定能显示的最大数额为50元（500角）；
disptime： 显示本次通话的时长；
write,read： 当write信号下降沿到来时写卡，当话卡插入，read信号变高时读卡；
warn： 余额过少时的告警信号。本例中，当打市话时，余额少于3角，打长
话时，余额少于6角，即会产生告警信号；
cut： 当告警时间过长时自动切断通话信号。 */
module account(state,clk,card,decide,disptime,dispmoney,
write,read,warn,cut);
output write,read,warn,cut;
input state,clk,card;
input[2:1] decide;
output[10:0] dispmoney;
output[8:0] disptime;
reg[10:0] money;
reg[8:0] dtime;
reg warn,cut,write,t1m; //t1m为分时钟
reg set,reset_ena;
integer num1,temp;
assign dispmoney=card?money:0;
assign disptime=dtime;
assign read=card?1:0;
always @(posedge clk)
begin
if (num1==59) begin num1<=0; t1m<=1; end
else begin
if(state) num1<=num1+1;
else num1<=0; t1m<=0;
end
end
always @(negedge clk) //该进程完成电话计费功能
begin
if(!set)
begin money<=11'h500; set<=1; end
if(card&state)
if(t1m)
case({state,decide})
3'b101: if(money<3)
begin warn<=1; write<=0; reset_ena<=1; end
else
begin //市话计费
if(money[3:0]<4'b0011)
begin
money[3:0]<=money[3:0]+7;
if(money[7:4]!=0)
money[7:4]<=money[7:4]-1;
else
begin money[7:4]<=9; money[10:8]<=money[10:8]-1; end
end
else money[3:0]<=money[3:0]-3; write<=1;
//市话通话计时
if(dtime[3:0]==9)
begin
dtime[3:0]<=0;
if(dtime[7:4]==9)
begin dtime[7:4]<=0; dtime[8]<=dtime[8]+1; end
else dtime[7:4]<=dtime[7:4]+1;
end
else
begin
dtime[3:0]<=dtime[3:0]+1; warn<=0; reset_ena<=0;
end
end
3'b110: if(money<6)
begin warn<=1; write<=0; reset_ena<=1; end
else begin
//通话计时
if(dtime[3:0]==9)
begin
dtime[3:0]<=0; if(dtime[7:4]==9)
begin dtime[7:4]<=0; dtime[8]<=dtime[8]+1; end
else dtime[7:4]<=dtime[7:4]+1;
end
else dtime[3:0]<=dtime[3:0]+1;
//长话计费
if(money[3:0]<4'b0110)
begin
money[3:0]<=money[3:0]+4;
if(!money[7:4])
begin money[7:4]<=9; money[10:8]<=money[10:8]-1; end
else money[7:4]<=money[7:4]-1;
end
else money[3:0]<=money[3:0]-6;
write<=1; reset_ena<=0; warn<=0;
end
endcase
else write<=0;
else begin dtime<=0; warn<=0; write<=0; reset_ena<=0; en
//取卡后对一些信号进行复位
end
always @(posedge clk) //该进程在告警时间过长的情况下切断本次通话
begin
if(warn) temp<=temp+1;
else temp<=0;
if(temp==15)
begin cut<=1; temp<=0; end
if(!card||!reset_ena)
begin
cut<=0; //复位cut信号
temp<=0;
end
end
endmodule
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