Apple-2-HW/GR8RAM
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This commit is contained in:
Zane Kaminski 2020-03-10 18:54:44 -04:00
parent ac8cf35610
commit 0ad3b4640a
1 changed files with 70 additions and 18 deletions
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cpld/GR8RAM.v
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@ -34,17 +34,26 @@ module GR8RAM(C7M, C7M_2, Q3, PHI0in, PHI1in, nRES, nMode,
( nIOSTRB & CASel & nIOSEL) ? Addr[7:0] : 8'h00;
/* Select Signals */
wire BankSELA = A[3:0]==4'hF;
wire RAMSELA = A[3:0]==4'h3;
wire AddrHSELA = A[3:0]==4'h2;
wire AddrMSELA = A[3:0]==4'h1;
wire AddrLSELA = A[3:0]==4'h0;
LCELL BankWR_MC (.in(BankSELA & ~nWE & ~nDEVSEL & REGEN), .out(BankWR)); wire BankWR;
LCELL SetWR_MC (.in(SetSELA & ~nWE & ~nDEVSEL & REGEN), .out(SetWR)); wire SetWR;
LCELL RAMSEL_MC (.in(RAMSELA & ~nDEVSEL & REGEN), .out(RAMSEL)); wire RAMSEL;
LCELL AddrHWR_MC (.in(AddrHSELA & ~nWE & ~nDEVSEL & REGEN), .out(AddrHWR)); wire AddrHWR;
LCELL AddrMWR_MC (.in(AddrMSELA & ~nWE & ~nDEVSEL & REGEN), .out(AddrMWR)); wire AddrMWR;
LCELL AddrLWR_MC (.in(AddrLSELA & ~nWE & ~nDEVSEL & REGEN), .out(AddrLWR)); wire AddrLWR;
wire BankSELA = A[3:0]==4'hF;
wire MagicSELA = A[3:0]==4'hE;
wire TCntHSELA = A[3:0]==4'hB;
wire TCntLSELA = A[3:0]==4'hA;
wire DestHSELA = A[3:0]==4'h9;
wire DestLSELA = A[3:0]==4'h8;
wire RAMSELA = A[3:0]==4'h3;
wire AddrHSELA = A[3:0]==4'h2;
wire AddrMSELA = A[3:0]==4'h1;
wire AddrLSELA = A[3:0]==4'h0;
LCELL BankWR_MC (.in(BankSELA & ~nWE & ~nDEVSEL & REGEN), .out(BankWR)); wire BankWR;
LCELL MagicWR_MC (.in(MagicSELA & ~nWE & ~nDEVSEL & REGEN), .out(MagicWR)); wire MagicWR;
LCELL TCntHWR_MC (.in(TCntHSELA & ~nWE & ~nDEVSEL & REGEN), .out(TCntHWR)); wire TCntHWR;
LCELL TCntLWR_MC (.in(TCntLSELA & ~nWE & ~nDEVSEL & REGEN), .out(TCntLWR)); wire TCntLWR;
LCELL DestHWR_MC (.in(DestHSELA & ~nWE & ~nDEVSEL & REGEN), .out(DestHWR)); wire DestHWR;
LCELL DestLWR_MC (.in(DestLSELA & ~nWE & ~nDEVSEL & REGEN), .out(DestLWR)); wire DestLWR;
LCELL RAMSEL_MC (.in(RAMSELA & ~nDEVSEL & REGEN), .out(RAMSEL)); wire RAMSEL;
LCELL AddrHWR_MC (.in(AddrHSELA & ~nWE & ~nDEVSEL & REGEN), .out(AddrHWR)); wire AddrHWR;
LCELL AddrMWR_MC (.in(AddrMSELA & ~nWE & ~nDEVSEL & REGEN), .out(AddrMWR)); wire AddrMWR;
LCELL AddrLWR_MC (.in(AddrLSELA & ~nWE & ~nDEVSEL & REGEN), .out(AddrLWR)); wire AddrLWR;
/* Data Bus Routing */
// DRAM/ROM data bus
@ -71,15 +80,20 @@ module GR8RAM(C7M, C7M_2, Q3, PHI0in, PHI1in, nRES, nMode,
reg REGEN = 0; // Register enable
reg IOROMEN = 0; // IOSTRB ROM enable
reg FullIOEN = 0; // Set to enable full I/O ROM space
reg PDMARDEN = 0;
reg PDMAWREN = 0;
reg [7:0] Bank = 0; // Bank register for ROM access
reg [23:0] Addr = 0; // RAM address register
/* Increment Control */
/* RAM Address Register Increment Control */
reg IncAddrL = 0, IncAddrM = 0, IncAddrH = 0;
/* Transfer Counters */
reg [15:0] TCnt = 0;
/* Pseudo-DMA Transfer Counters */
reg [9:0] TCnt = 0;
reg [15:0] Dest = 0;
/* Transfer Counter Increment Control */
reg PDMANext = 0, IncDestH = 0;
/* CAS rising/falling edge components */
// These are combined to create the CAS outputs.
@ -164,19 +178,21 @@ module GR8RAM(C7M, C7M_2, Q3, PHI0in, PHI1in, nRES, nMode,
Addr <= 0;
Bank <= 0;
FullIOEN <= 0;
PDMARDEN <= 0;
PDMAWREN <= 0;
IncAddrL <= 0;
IncAddrM <= 0;
IncAddrH <= 0;
end else begin
// Increment address register
if (S==1 & IncAddrL) begin
Addr[7:0] <= Addr[7:0]+1;
IncAddrL <= 0;
Addr[7:0] <= Addr[7:0]+1;
IncAddrM <= Addr[7:0] == 8'hFF;
end
if (S==2 & IncAddrM) begin
Addr[15:8] <= Addr[15:8]+1;
IncAddrM <= 0;
Addr[15:8] <= Addr[15:8]+1;
IncAddrH <= Addr[15:8] == 8'hFF;
end
if (S==3 & IncAddrH) begin
@ -186,8 +202,12 @@ module GR8RAM(C7M, C7M_2, Q3, PHI0in, PHI1in, nRES, nMode,
// Set register in middle of S6 if accessed.
if (S==6) begin
if (BankWR) Bank[7:0] <= D[7:0]; // Bank
if (SetWR) FullIOEN <= D[7:0] == 8'hE5;
if (BankWR) begin
Bank[7:0] <= D[7:0];
PDMARDEN <= D[7:0]==8'h10 & FullIOEN;
PDMAWREN <= D[7:0]==8'h10 & FullIOEN;
end
if (MagicWR) FullIOEN <= D[7:0] == 8'hE5;
IncAddrL <= RAMSEL;
IncAddrM <= AddrLWR & Addr[7] & ~D[7];
@ -200,6 +220,38 @@ module GR8RAM(C7M, C7M_2, Q3, PHI0in, PHI1in, nRES, nMode,
end
end
/* Pseudo-DMA transfer counters */
always @(negedge C7M, negedge nRES) begin
if (~nRES) begin
TCnt <= 0;
Dest <= 0;
PDMANext <= 0;
IncDestH <= 0;
end else begin
// Increment destination pointer and decrement transfer counter
if (S==1 & PDMANext) begin
PDMANext <= 0;
Dest[7:0] <= Dest[7:0]+1;
IncDestH <= Dest[7:0] == 8'hFF;
TCnt <= TCnt-1;
end
if (S==2 & IncDestH) begin
IncDestH <= 0;
Dest[15:8] <= Dest[15:8]+1;
end
// Set register in middle of S6 if accessed.
if (S==6) begin
PDMANext <= RAMSEL;
if (TCntHWR) TCnt[15:8] <= D[7:0]; // TCnt hi
if (TCntLWR) TCnt[7:0] <= D[7:0]; // TCnt lo
if (DestHWR) Dest[15:8] <= D[7:0]; // Dest hi
if (DestLWR) Dest[7:0] <= D[7:0]; // Dest lo
end
end
end
/* DRAM RAS/CAS */
always @(posedge C7M) begin
RASr <= (S==1 & Ref==0) | // Refresh