Add mock up LCDC
authorJoshua Wise <joshua@rebirth.joshuawise.com>
Sun, 13 Apr 2008 09:44:09 +0000 (05:44 -0400)
committerJoshua Wise <joshua@rebirth.joshuawise.com>
Sun, 13 Apr 2008 09:44:09 +0000 (05:44 -0400)
LCDC.v [new file with mode: 0644]
Makefile
System.v
diag.asm

diff --git a/LCDC.v b/LCDC.v
new file mode 100644 (file)
index 0000000..41b5500
--- /dev/null
+++ b/LCDC.v
@@ -0,0 +1,104 @@
+`define ADDR_LCDC      16'hFF40
+`define ADDR_STAT      16'hFF41
+`define ADDR_SCY       16'hFF42
+`define ADDR_SCX       16'hFF43
+`define ADDR_LY                16'hFF44
+`define ADDR_LYC       16'hFF45
+`define ADDR_DMA       16'hFF46
+`define ADDR_BGP       16'hFF47
+`define ADDR_OBP0      16'hFF48
+`define ADDR_OBP1      16'hFF49
+`define ADDR_WY                16'hFF4A
+`define ADDR_WX                16'hFF4B
+
+module LCDC(
+       input [15:0] addr,
+       inout [7:0] data,
+       input clk,      // 8MHz clock
+       input wr, rd,
+       output reg irq = 0);
+       
+       /***** Internal clock that is stable and does not depend on CPU in single/double clock mode *****/
+       reg clk4 = 0;
+       always @(posedge clk)
+               clk4 = ~clk4;
+       
+       /***** Sync generation *****/
+       
+       /* A complete cycle takes 456 clocks.
+        * VBlank lasts 4560 clocks (10 scanlines) -- LY = 144 - 153.
+        *
+        * Modes: 0 -> in hblank and OAM/VRAM available - present 207 clks
+        *        1 -> in vblank and OAM/VRAM available
+        *        2 -> OAM in use - present 83 clks
+        *        3 -> OAM/VRAM in use - present 166 clks
+        * So, X = 0~165 is HActive,
+        * X = 166-372 is HBlank,
+        * X = 373-455 is HWhirrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr.
+        */
+       reg [8:0] posx = 9'h000;
+       reg [7:0] posy = 8'h00;
+       wire [1:0] mode = (posy < 144) ?
+                               ((posx < 166) ? 2'b11 :
+                                (posx < 373) ? 2'b00 :
+                                2'b10)
+                               : 2'b01;
+       
+       always @(posedge clk)
+       begin
+               if (posx == 455) begin
+                       posx <= 0;
+                       if (posy == 153)
+                               posy <= 0;
+                       else
+                               posy <= posy + 1;
+               end else
+                       posx <= posx + 1;
+       end
+  
+       /***** Bus interface *****/
+       reg [7:0] rLCDC = 8'h91;
+       reg [7:0] rSTAT = 8'h00;
+       reg [7:0] rSCY = 8'b00;
+       reg [7:0] rSCX = 8'b00;
+       reg [7:0] rLYC = 8'b00;
+       reg [7:0] rDMA = 8'b00;
+       reg [7:0] rBGP = 8'b00;
+       reg [7:0] rOBP0 = 8'b00;
+       reg [7:0] rOBP1 = 8'b00;
+       reg [7:0] rWY = 8'b00;
+       reg [7:0] rWX = 8'b00;
+       
+       assign data = rd ?
+                       (addr == `ADDR_LCDC) ? rLCDC :
+                       (addr == `ADDR_STAT) ? {rSTAT[7:3], (rLYC == posy) ? 1'b1 : 1'b0, mode} :
+                       (addr == `ADDR_SCY) ? rSCY :
+                       (addr == `ADDR_SCX) ? rSCX :
+                       (addr == `ADDR_LY) ? posy :
+                       (addr == `ADDR_LYC) ? rLYC :
+                       (addr == `ADDR_BGP) ? rBGP :
+                       (addr == `ADDR_OBP0) ? rOBP0 :
+                       (addr == `ADDR_OBP1) ? rOBP1 :
+                       (addr == `ADDR_WY) ? rWY :
+                       (addr == `ADDR_WX) ? rWX :
+                       8'bzzzzzzzz :
+               8'bzzzzzzzz;
+  
+       always @(negedge clk)
+       begin
+               if (wr)
+                       case (addr)
+                       `ADDR_LCDC:     rLCDC <= data;
+                       `ADDR_STAT:     rSTAT <= {data[7:2],rSTAT[1:0]};
+                       `ADDR_SCY:      rSCY <= data;
+                       `ADDR_SCX:      rSCX <= data;
+                       `ADDR_LYC:      rLYC <= data;
+                       `ADDR_DMA:      rDMA <= data;
+                       `ADDR_BGP:      rBGP <= data;
+                       `ADDR_OBP0:     rOBP0 <= data;
+                       `ADDR_OBP1:     rOBP1 <= data;
+                       `ADDR_WY:       rWY <= data;
+                       `ADDR_WX:       rWX <= data;
+                       endcase
+       end
+endmodule
index 26e2289..9d94442 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,7 @@ VLOGS = 7seg.v GBZ80Core.v insn_call-callcc.v insn_incdec16.v \
        insn_ld_sp_hl.v insn_pop_reg.v insn_rst.v System.v CPUDCM.v \
        insn_alu_a.v insn_halt.v insn_jp-jpcc.v insn_ld_hl_reg.v \
        insn_ld_reg_imm8.v insn_ldx_ahl.v insn_push_reg.v insn_vop_intr.v \
-       Timer.v
+       Timer.v LCDC.v insn_ldm_a.v
 
 all: CoreTop_rom.svf CoreTop_diag.svf CoreTop.twr
 
index 5b0fb3c..712dd75 100644 (file)
--- a/System.v
+++ b/System.v
@@ -76,7 +76,7 @@ module CoreTop(
        wire [7:0] data;
        wire wr, rd;
        
-       wire irq, tmrirq;
+       wire irq, tmrirq, lcdcirq;
        wire [7:0] jaddr;
        wire [1:0] state;
        
@@ -97,6 +97,14 @@ module CoreTop(
                .wr(wr),
                .rd(rd));
        
+       LCDC lcdc(
+               .addr(addr),
+               .data(data),
+               .clk(clk),
+               .wr(wr),
+               .rd(rd),
+               .irq(lcdcirq));
+       
        AddrMon amon(
                .addr(addr), 
                .clk(clk), 
@@ -152,7 +160,7 @@ module CoreTop(
                .addr(addr),
                .data(data),
                .vblank(0),
-               .lcdc(0),
+               .lcdc(lcdcirq),
                .tovf(tmrirq),
                .serial(0),
                .buttons(0),
index 55127f8..ff70e07 100644 (file)
--- a/diag.asm
+++ b/diag.asm
@@ -1,15 +1,13 @@
        SECTION "a",HOME
 
 main:
-       ld c, $51       ; Note that we are alive.
        ld a, $FF
-       ld [c],a
+       ld [$FF51],a
        
        ld sp, $DFF0
        
-       ld c, $07
        ld a, $04       ;start timer, 4.096KHz
-       ld [c], a
+       ld [$FF07], a
 
        ld hl, $DF81
        xor a
@@ -42,8 +40,7 @@ irqhand:
        PUSH HL
        
        xor a
-       ld c, $0F       ; ack the irq
-       ld [c], a
+       ld [$FF0F], a
        
        ld hl, $DF82
        ld a, [hld]
@@ -54,8 +51,7 @@ irqhand:
 .noprint:
        inc [hl]
        ld a, [hl]
-       ld c, $51
-       ld [c], a
+       ld [$FF51], a
 
        POP HL
        POP DE
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