pci9054 局部总线控制器代码

i2cbus · 发表于 2008-10-30 21:38:32

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//*******************fsm**********************
always @(posedge lclk)
if (reset)
Pci_Csta <= s0_idle;
else
Pci_Csta <= Pci_Nsta;

//Next state logic
always @ (ads_b or blast_b or  Pci_Csta)  //rdy_b or  or lclk
begin
      Pci_Nsta=Pci_Csta;
case (Pci_Csta)
s0_idle: if (!ads_b)
Pci_Nsta = s1_start;
else
Pci_Nsta = s0_idle;

s1_start: if (!blast_b)
Pci_Nsta = s2_single_wait;
else if (blast_b)
Pci_Nsta = s4_burst_wait;
else
Pci_Nsta = s1_start;

s2_single_wait:
Pci_Nsta = s3_single_last;

s3_single_last: if (!ads_b)
Pci_Nsta = s1_start;
else
Pci_Nsta = s0_idle;

s4_burst_wait: Pci_Nsta = s5_burst_repeat;

s5_burst_repeat: if (blast_b)
Pci_Nsta = s5_burst_repeat;
else
Pci_Nsta = s6_burst_last;

s6_burst_last: if (!ads_b)
Pci_Nsta = s1_start;
else
Pci_Nsta = s0_idle;

default:
Pci_Nsta = s0_idle;
endcase
end

//output logic
always @ (posedge lclk)
begin
lrdy<=1'b1;
case(Pci_Nsta)
s0_idle: begin
lrdy <=1;
// watch_sta<=3'b000;
end

s1_start: begin
lrdy <=1;
// watch_sta<=3'b001;
end

s2_single_wait: begin
lrdy<=0;//2008/07/04 15:33
// watch_sta<=3'b010;
end

s3_single_last: begin
lrdy<=1;
// watch_sta<=3'b011;
end

s4_burst_wait: begin
lrdy<=1;
// watch_sta<=3'b100;
end

s5_burst_repeat: begin
lrdy<=0;
// watch_sta<=3'b101;
end

s6_burst_last: begin
lrdy<=1;
// watch_sta<=3'b110;
end

default: begin
lrdy<=1;
// watch_sta<=3'b110;
end
endcase
   end

//------------------------------------------------
// local bus arbitration
always @(posedge lclk)
if (lhold)
lholda <= lhold;
else
lholda <= 1'b0;