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Gameboy_MiSTer/Gameboy.sv
sorgelig 0fcfcaf4f3 remove fast boot option. It's byggy.
2019-02-13 15:46:38 +08:00

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//============================================================================
// Gameboy
// Copyright (c) 2015 Till Harbaum <till@harbaum.org>
//
// Port to MiSTer
// Copyright (C) 2017,2018 Sorgelig
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 of the License, or (at your option)
// any later version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
// more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//============================================================================
module emu
(
//Master input clock
input CLK_50M,
//Async reset from top-level module.
//Can be used as initial reset.
input RESET,
//Must be passed to hps_io module
inout [44:0] HPS_BUS,
//Base video clock. Usually equals to CLK_SYS.
output CLK_VIDEO,
//Multiple resolutions are supported using different CE_PIXEL rates.
//Must be based on CLK_VIDEO
output CE_PIXEL,
//Video aspect ratio for HDMI. Most retro systems have ratio 4:3.
output [7:0] VIDEO_ARX,
output [7:0] VIDEO_ARY,
output [7:0] VGA_R,
output [7:0] VGA_G,
output [7:0] VGA_B,
output VGA_HS,
output VGA_VS,
output VGA_DE, // = ~(VBlank | HBlank)
output VGA_F1,
output [1:0] VGA_SL,
output LED_USER, // 1 - ON, 0 - OFF.
// b[1]: 0 - LED status is system status OR'd with b[0]
// 1 - LED status is controled solely by b[0]
// hint: supply 2'b00 to let the system control the LED.
output [1:0] LED_POWER,
output [1:0] LED_DISK,
output [15:0] AUDIO_L,
output [15:0] AUDIO_R,
output AUDIO_S, // 1 - signed audio samples, 0 - unsigned
output [1:0] AUDIO_MIX, // 0 - no mix, 1 - 25%, 2 - 50%, 3 - 100% (mono)
input TAPE_IN,
// SD-SPI
output SD_SCK,
output SD_MOSI,
input SD_MISO,
output SD_CS,
input SD_CD,
//High latency DDR3 RAM interface
//Use for non-critical time purposes
output DDRAM_CLK,
input DDRAM_BUSY,
output [7:0] DDRAM_BURSTCNT,
output [28:0] DDRAM_ADDR,
input [63:0] DDRAM_DOUT,
input DDRAM_DOUT_READY,
output DDRAM_RD,
output [63:0] DDRAM_DIN,
output [7:0] DDRAM_BE,
output DDRAM_WE,
//SDRAM interface with lower latency
output SDRAM_CLK,
output SDRAM_CKE,
output [12:0] SDRAM_A,
output [1:0] SDRAM_BA,
inout [15:0] SDRAM_DQ,
output SDRAM_DQML,
output SDRAM_DQMH,
output SDRAM_nCS,
output SDRAM_nCAS,
output SDRAM_nRAS,
output SDRAM_nWE,
input UART_CTS,
output UART_RTS,
input UART_RXD,
output UART_TXD,
output UART_DTR,
input UART_DSR,
input OSD_STATUS
);
assign {DDRAM_CLK, DDRAM_BURSTCNT, DDRAM_ADDR, DDRAM_DIN, DDRAM_BE, DDRAM_RD, DDRAM_WE} = 0;
assign VGA_F1 = 0;
assign {UART_RTS, UART_TXD, UART_DTR} = 0;
assign {SD_SCK, SD_MOSI, SD_CS} = 'Z;
assign LED_USER = ioctl_download | sav_pending;
assign LED_DISK = 0;
assign LED_POWER = 0;
assign VIDEO_ARX = status[4:3] == 2'b10 ? 8'd16:
status[4:3] == 2'b01 ? 8'd10:
8'd4;
assign VIDEO_ARY = status[4:3] == 2'b10 ? 8'd9:
status[4:3] == 2'b01 ? 8'd9:
8'd3;
assign AUDIO_MIX = status[8:7];
`include "build_id.v"
localparam CONF_STR1 = {
"GAMEBOY;;",
"-;",
"FS,GBCGB ,Load ROM;",
"OEF,System,Auto,Gameboy,Gameboy Color;",
"-;",
"OC,Inverted color,No,Yes;",
"O1,Palette,Grayscale,Custom;"
};
localparam CONF_STR2 = {
",GBP,Load Palette;",
"-;",
"OD,OSD triggered autosaves,No,Yes;",
};
localparam CONF_STR3 = {
"9,Load Backup RAM;"
};
localparam CONF_STR4 = {
"A,Save Backup RAM;",
"-;",
"O34,Aspect ratio,4:3,10:9,16:9;",
"O78,Stereo mix,none,25%,50%,100%;",
"-;",
"R0,Reset;",
"J1,A,B,Select,Start;",
"V,v",`BUILD_DATE
};
//////////////////// CLOCKS ///////////////////
wire clk_sys;
wire pll_locked;
pll pll
(
.refclk(CLK_50M),
.rst(0),
.outclk_0(clk_sys),
.outclk_1(SDRAM_CLK),
.locked(pll_locked)
);
///////////////////////////////////////////////////
wire [31:0] status;
wire [1:0] buttons;
wire ioctl_download;
wire ioctl_wr;
wire [24:0] ioctl_addr;
wire [15:0] ioctl_dout;
reg ioctl_wait;
wire [15:0] joystick_0, joystick_1;
wire [15:0] joystick = joystick_0 | joystick_1;
wire [7:0] filetype;
reg [31:0] sd_lba;
reg sd_rd = 0;
reg sd_wr = 0;
wire sd_ack;
wire [7:0] sd_buff_addr;
wire [15:0] sd_buff_dout;
wire [15:0] sd_buff_din;
wire sd_buff_wr;
wire img_mounted;
wire img_readonly;
wire [63:0] img_size;
wire [7:0] sav_char = sav_supported ? "R" : "+";
hps_io #(.STRLEN(($size(CONF_STR1)>>3) + ($size(CONF_STR2)>>3) + ($size(CONF_STR3)>>3) + ($size(CONF_STR4)>>3) + 3), .WIDE(1)) hps_io
(
.clk_sys(clk_sys),
.HPS_BUS(HPS_BUS),
.conf_str({CONF_STR1,status[1]?"F":"+",CONF_STR2, sav_char, CONF_STR3, sav_char, CONF_STR4}),
.ioctl_download(ioctl_download),
.ioctl_wr(ioctl_wr),
.ioctl_addr(ioctl_addr),
.ioctl_dout(ioctl_dout),
.ioctl_wait(ioctl_wait),
.ioctl_index(filetype),
.sd_lba(sd_lba),
.sd_rd(sd_rd),
.sd_wr(sd_wr),
.sd_ack(sd_ack),
.sd_buff_addr(sd_buff_addr),
.sd_buff_dout(sd_buff_dout),
.sd_buff_din(sd_buff_din),
.sd_buff_wr(sd_buff_wr),
.img_mounted(img_mounted),
.img_readonly(img_readonly),
.img_size(img_size),
.buttons(buttons),
.status(status),
.joystick_0(joystick_0),
.joystick_1(joystick_1)
);
///////////////////////////////////////////////////
wire cart_download = ioctl_download && (filetype == 8'h01 || filetype == 8'h41 || filetype == 8'h80);
wire palette_download = ioctl_download && (filetype == 8'h05 || filetype == 8'h00);
wire bios_download = ioctl_download && (filetype == 8'h40);
wire [1:0] sdram_ds = cart_download ? 2'b11 : {cart_addr[0], ~cart_addr[0]};
wire [15:0] sdram_do;
wire [15:0] sdram_di = cart_download ? ioctl_dout : 16'd0;
wire [23:0] sdram_addr = cart_download? ioctl_addr[24:1]: {2'b00, mbc_bank, cart_addr[12:1]};
wire sdram_oe = ~cart_download & cart_rd & ~cram_rd;
wire sdram_we = cart_download & dn_write;
assign SDRAM_CKE = 1;
sdram sdram (
// interface to the MT48LC16M16 chip
.sd_data ( SDRAM_DQ ),
.sd_addr ( SDRAM_A ),
.sd_dqm ( {SDRAM_DQMH, SDRAM_DQML} ),
.sd_cs ( SDRAM_nCS ),
.sd_ba ( SDRAM_BA ),
.sd_we ( SDRAM_nWE ),
.sd_ras ( SDRAM_nRAS ),
.sd_cas ( SDRAM_nCAS ),
// system interface
.clk ( clk_sys ),
.sync ( ce_cpu2x ),
.init ( ~pll_locked ),
// cpu interface
.din ( sdram_di ),
.addr ( sdram_addr ),
.ds ( sdram_ds ),
.we ( sdram_we ),
.oe ( sdram_oe ),
.dout ( sdram_do )
);
reg cart_ready = 0;
reg dn_write;
always @(posedge clk_sys) begin
if(ioctl_wr) ioctl_wait <= 1;
if(speed?ce_cpu2x:ce_cpu) begin
dn_write <= ioctl_wait;
if(dn_write) {ioctl_wait, dn_write} <= 0;
if(dn_write) cart_ready <= 1;
end
end
///////////////////////////////////////////////////
// http://fms.komkon.org/GameBoy/Tech/Carts.html
// 32MB SDRAM memory map using word addresses
// 2 2 2 2 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 D
// 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 S
// -------------------------------------------------
// 0 0 0 0 X X X X X X X X X X X X X X X X X X X X X up to 2MB used as ROM (MBC1-3), 8MB for MBC5
// 0 0 0 0 R R B B B B B C C C C C C C C C C C C C C MBC1 ROM (R=RAM bank in mode 0)
// ---------------------------------------------------------------
// ----------------------------- MBC1 ----------------------------
// ---------------------------------------------------------------
wire [9:0] mbc1_addr =
(cart_addr[15:14] == 2'b00)?{9'd0, cart_addr[13]}: // 16k ROM Bank 0
(cart_addr[15:14] == 2'b01)?{2'b00, mbc1_rom_bank, cart_addr[13]}: // 16k ROM Bank 1-127
9'd0;
wire [9:0] mbc2_addr =
(cart_addr[15:14] == 2'b00)?{9'd0, cart_addr[13]}: // 16k ROM Bank 0
(cart_addr[15:14] == 2'b01)?{2'b00, mbc2_rom_bank, cart_addr[13]}: // 16k ROM Bank 1-15
9'd0;
wire [9:0] mbc3_addr =
(cart_addr[15:14] == 2'b00)?{9'd0, cart_addr[13]}: // 16k ROM Bank 0
(cart_addr[15:14] == 2'b01)?{2'b00,mbc3_rom_bank, cart_addr[13]}: // 16k ROM Bank 1-127
9'd0;
wire [9:0] mbc5_addr =
(cart_addr[15:14] == 2'b00)?{9'd0, cart_addr[13]}: // 16k ROM Bank 0
(cart_addr[15:14] == 2'b01)?{mbc5_rom_bank, cart_addr[13]}: // 16k ROM Bank 0-480 (0h-1E0h)
9'd0;
// -------------------------- RAM banking ------------------------
// in mode 0 (16/8 mode) the ram is not banked
// in mode 1 (4/32 mode) four ram banks are used
wire [1:0] mbc1_ram_bank = (mbc1_mode?mbc_ram_bank_reg[1:0]:2'b00) & ram_mask[1:0];
wire [1:0] mbc3_ram_bank = mbc_ram_bank_reg[1:0] & ram_mask[1:0];
wire [3:0] mbc5_ram_bank = mbc_ram_bank_reg & ram_mask;
// -------------------------- ROM banking ------------------------
// in mode 0 (16/8 mode) the ram bank select signals are the upper rom address lines
// in mode 1 (4/32 mode) the upper two rom address lines are 2'b00
wire [6:0] mbc1_rom_bank_mode = { mbc1_mode?2'b00:mbc_ram_bank_reg[1:0], mbc_rom_bank_reg[4:0]};
// in mode 0 map memory at A000-BFFF
// in mode 1 map rtc register at A000-BFFF
//wire [6:0] mbc3_ram_bank_addr = { mbc3_mode?2'b00:mbc3_ram_bank_reg, mbc3_rom_bank_reg};
// mask address lines to enable proper mirroring
wire [6:0] mbc1_rom_bank = mbc1_rom_bank_mode & rom_mask[6:0]; //128
wire [6:0] mbc2_rom_bank = mbc_rom_bank_reg[6:0] & rom_mask[6:0]; //16
wire [6:0] mbc3_rom_bank = mbc_rom_bank_reg[6:0] & rom_mask[6:0]; //128
wire [8:0] mbc5_rom_bank = mbc_rom_bank_reg & rom_mask; //480
wire mbc_battery = (cart_mbc_type == 8'h03) || (cart_mbc_type == 8'h06) || (cart_mbc_type == 8'h09) || (cart_mbc_type == 8'h0D) ||
(cart_mbc_type == 8'h10) || (cart_mbc_type == 8'h13) || (cart_mbc_type == 8'h1B) || (cart_mbc_type == 8'h1E) ||
(cart_mbc_type == 8'h22) || (cart_mbc_type == 8'hFF);
// --------------------- CPU register interface ------------------
reg mbc_ram_enable;
reg mbc1_mode;
reg mbc3_mode;
reg [8:0] mbc_rom_bank_reg;
reg [3:0] mbc_ram_bank_reg; //0-15
always @(posedge clk_sys) begin
if(reset) begin
mbc_rom_bank_reg <= 5'd1;
mbc_ram_bank_reg <= 4'd0;
mbc1_mode <= 1'b0;
mbc3_mode <= 1'b0;
mbc_ram_enable <= 1'b0;
end else if(ce_cpu2x) begin
//write to ROM bank register
if(cart_wr && (cart_addr[15:13] == 3'b001)) begin
if(~mbc5 && cart_di[6:0]==0) //special case mbc1-3 rombank 0=1
mbc_rom_bank_reg <= 5'd1;
else if (mbc5) begin
if (cart_addr[13:12] == 2'b11) //3000-3FFF High bit
mbc_rom_bank_reg[8] <= cart_di[0];
else //2000-2FFF low 8 bits
mbc_rom_bank_reg[7:0] <= cart_di[7:0];
end else
mbc_rom_bank_reg <= {2'b00,cart_di[6:0]}; //mbc1-3
end
//write to RAM bank register
if(cart_wr && (cart_addr[15:13] == 3'b010)) begin
if (mbc3) begin
if (cart_di[3]==1)
mbc3_mode <= 1'b1; //enable RTC
else begin
mbc3_mode <= 1'b0; //enable RAM
mbc_ram_bank_reg <= {2'b00,cart_di[1:0]};
end
end else
if (mbc5)//can probably be simplified
mbc_ram_bank_reg <= cart_di[3:0];
else
mbc_ram_bank_reg <= {2'b00,cart_di[1:0]};
end
// MBC1 ROM/RAM Mode Select
if(mbc1 && cart_wr && (cart_addr[15:13] == 3'b011))
mbc1_mode <= cart_di[0];
//RAM enable/disable
if(ce_cpu2x && cart_wr && (cart_addr[15:13] == 3'b000))
mbc_ram_enable <= (cart_di[3:0] == 4'ha);
end
end
// extract header fields extracted from cartridge
// during download
reg [7:0] cart_mbc_type;
reg [7:0] cart_rom_size;
reg [7:0] cart_ram_size;
reg [7:0] cart_cgb_flag;
// RAM size
wire [3:0] ram_mask = // 0 - no ram
(cart_ram_size == 1)?4'b0000: // 1 - 2k, 1 bank
(cart_ram_size == 2)?4'b0000: // 2 - 8k, 1 bank
(cart_ram_size == 3)?4'b0011: // 3 - 32k, 4 banks
4'b1111; // 4 - 128k 16 banks
// ROM size
wire [8:0] rom_mask = // 0 - 2 banks, 32k direct mapped
(cart_rom_size == 1)? 9'b000000011: // 1 - 4 banks = 64k
(cart_rom_size == 2)? 9'b000000111: // 2 - 8 banks = 128k
(cart_rom_size == 3)? 9'b000001111: // 3 - 16 banks = 256k
(cart_rom_size == 4)? 9'b000011111: // 4 - 32 banks = 512k
(cart_rom_size == 5)? 9'b000111111: // 5 - 64 banks = 1M
(cart_rom_size == 6)? 9'b001111111: // 6 - 128 banks = 2M
(cart_rom_size == 7)? 9'b011111111: // 7 - 256 banks = 4M
(cart_rom_size == 8)? 9'b111111111: // 8 - 512 banks = 8M
(cart_rom_size == 82)?9'b001111111: //$52 - 72 banks = 1.1M
(cart_rom_size == 83)?9'b001111111: //$53 - 80 banks = 1.2M
(cart_rom_size == 84)?9'b001111111:
9'b001111111; //$54 - 96 banks = 1.5M
wire mbc1 = (cart_mbc_type == 1) || (cart_mbc_type == 2) || (cart_mbc_type == 3);
wire mbc2 = (cart_mbc_type == 5) || (cart_mbc_type == 6);
//wire mmm01 = (cart_mbc_type == 11) || (cart_mbc_type == 12) || (cart_mbc_type == 13) || (cart_mbc_type == 14);
wire mbc3 = (cart_mbc_type == 15) || (cart_mbc_type == 16) || (cart_mbc_type == 17) || (cart_mbc_type == 18) || (cart_mbc_type == 19);
//wire mbc4 = (cart_mbc_type == 21) || (cart_mbc_type == 22) || (cart_mbc_type == 23);
wire mbc5 = (cart_mbc_type == 25) || (cart_mbc_type == 26) || (cart_mbc_type == 27) || (cart_mbc_type == 28) || (cart_mbc_type == 29) || (cart_mbc_type == 30);
//wire tama5 = (cart_mbc_type == 253);
//wire tama6 = (cart_mbc_type == ???);
//wire HuC1 = (cart_mbc_type == 254);
//wire HuC3 = (cart_mbc_type == 255);
wire [9:0] mbc_bank =
mbc1?mbc1_addr: // MBC1, 16k bank 0, 16k bank 1-127 + ram
mbc2?mbc2_addr: // MBC2, 16k bank 0, 16k bank 1-15 + ram
mbc3?mbc3_addr:
mbc5?mbc5_addr:
// tama5?tama5_addr:
// HuC1?HuC1_addr:
// HuC3?HuC3_addr:
{8'd0, cart_addr[14:13]}; // no MBC, 32k linear address
wire isGBC_game = (cart_cgb_flag == 8'h80 || cart_cgb_flag == 8'hC0);
reg [127:0] palette = 128'h828214517356305A5F1A3B4900000000;
always @(posedge clk_sys) begin
if(!pll_locked) begin
cart_mbc_type <= 8'h00;
cart_rom_size <= 8'h00;
cart_ram_size <= 8'h00;
end else begin
if(cart_download & ioctl_wr) begin
case(ioctl_addr)
'h142: cart_cgb_flag <= ioctl_dout[15:8];
'h146: cart_mbc_type <= ioctl_dout[15:8];
'h148: { cart_ram_size, cart_rom_size } <= ioctl_dout;
endcase
end
end
if (palette_download & ioctl_wr) begin
palette[127:0] <= {palette[111:0], ioctl_dout[7:0], ioctl_dout[15:8]};
end
end
//TODO: e.g. output and read timer register values from mbc3 when selected
wire [7:0] cart_di; // data from cpu to cart
wire [7:0] cart_do =
~cart_ready ?
8'h00 :
cram_rd ?
cram_do :
cart_addr[0] ?
sdram_do[15:8]:
sdram_do[7:0];
wire [15:0] cart_addr;
wire cart_rd;
wire cart_wr;
wire lcd_clkena;
wire [14:0] lcd_data;
wire [1:0] lcd_mode;
wire lcd_on;
assign AUDIO_S = 0;
wire reset = (RESET | status[0] | buttons[1] | cart_download | bk_loading);
wire speed;
reg isGBC = 0;
always @(posedge clk_sys) if(reset) isGBC <= status[15:14] ? status[15] : !filetype[7:4];
// the gameboy itself
gb gb (
.reset ( reset ),
.clk ( clk_cpu ), // the whole gameboy runs on 4mhnz
.clk2x ( clk_cpu2x ), // ~8MHz in dualspeed mode (GBC)
.fast_boot ( 0 ),
.joystick ( joystick ),
.isGBC ( isGBC ),
.isGBC_game ( isGBC_game ),
// interface to the "external" game cartridge
.cart_addr ( cart_addr ),
.cart_rd ( cart_rd ),
.cart_wr ( cart_wr ),
.cart_do ( cart_do ),
.cart_di ( cart_di ),
//gbc bios interface
.gbc_bios_addr ( bios_addr ),
.gbc_bios_do ( bios_do ),
// audio
.audio_l ( AUDIO_L ),
.audio_r ( AUDIO_R ),
// interface to the lcd
.lcd_clkena ( lcd_clkena ),
.lcd_data ( lcd_data ),
.lcd_mode ( lcd_mode ),
.lcd_on ( lcd_on ),
.speed ( speed )
);
// the lcd to vga converter
wire [7:0] video_r, video_g, video_b;
wire video_hs, video_vs, video_bl;
lcd lcd (
.pclk ( clk_sys_old),
.pce ( ce_pix ),
.clk ( clk_cpu ),
.isGBC ( isGBC ),
.tint ( status[1] ),
.inv ( status[12] ),
// Palettes
.pal1 (palette[127:104]),
.pal2 (palette[103:80]),
.pal3 (palette[79:56]),
.pal4 (palette[55:32]),
// serial interface
.clkena ( lcd_clkena ),
.data ( lcd_data ),
.mode ( lcd_mode ), // used to detect begin of new lines and frames
.on ( lcd_on ),
.hs ( video_hs ),
.vs ( video_vs ),
.blank ( video_bl ),
.r ( video_r ),
.g ( video_g ),
.b ( video_b )
);
assign VGA_SL = 0;
assign VGA_R = video_r;
assign VGA_G = video_g;
assign VGA_B = video_b;
assign VGA_DE = ~video_bl;
assign CLK_VIDEO = clk_sys;
assign CE_PIXEL = ce_pix & !line_cnt;
assign VGA_HS = video_hs;
assign VGA_VS = video_vs;
wire clk_sys_old = clk_sys & ce_sys;
wire ce_cpu2x = ce_pix;
wire clk_cpu = clk_sys & ce_cpu;
wire clk_cpu2x = clk_sys & ce_pix;
reg ce_pix, ce_cpu,ce_sys;
always @(negedge clk_sys) begin
reg [3:0] div = 0;
div <= div + 1'd1;
ce_sys <= !div[0];
ce_pix <= !div[2:0];
ce_cpu <= !div[3:0];
end
///////////////////////////// GBC BIOS /////////////////////////////////
wire [7:0] bios_do;
wire [11:0] bios_addr;
dpram_dif #(12,8,11,16) boot_rom_gbc (
.clock (clk_sys),
.address_a (bios_addr),
.wren_a (),
.data_a (),
.q_a (bios_do),
.address_b (ioctl_addr[11:1]),
.wren_b (ioctl_wr && bios_download),
.data_b (ioctl_dout),
.q_b ()
);
///////////////////////// BRAM SAVE/LOAD /////////////////////////////
wire [16:0] bk_addr = {sd_lba[7:0],sd_buff_addr};
wire bk_wr = sd_buff_wr & sd_ack;
wire [15:0] bk_data = sd_buff_dout;
wire [15:0] bk_q;
assign sd_buff_din = bk_q;
wire [7:0] cram_do =
mbc_ram_enable ?
((cart_addr[15:9] == 7'b1010000) && mbc2) ?
{4'hF,cram_q[3:0]} : // 4 bit MBC2 Ram needs top half masked.
mbc3_mode ?
8'h0: // RTC mode
cram_q : // Return normal value
8'hFF; // Ram not enabled
wire [7:0] cram_q = cram_addr[0] ? cram_q_h : cram_q_l;
wire [7:0] cram_q_h;
wire [7:0] cram_q_l;
wire is_cram_addr = (cart_addr[15:13] == 3'b101);
wire cram_rd = cart_rd & is_cram_addr;
wire cram_wr = cart_wr & is_cram_addr;
wire [16:0] cram_addr = mbc1? {2'b00,mbc1_ram_bank, cart_addr[12:0]}:
mbc3? {2'b00,mbc3_ram_bank, cart_addr[12:0]}:
mbc5? {mbc5_ram_bank, cart_addr[12:0]}:
{4'd0, cart_addr[12:0]};
// Up to 8kb * 16banks of Cart Ram (128kb)
dpram #(16) cram_l (
.clock_a (clk_cpu2x),
.address_a (cram_addr[16:1]),
.wren_a (cram_wr & ~cram_addr[0]),
.data_a (cart_di),
.q_a (cram_q_l),
.clock_b (clk_sys),
.address_b (bk_addr[15:0]),
.wren_b (bk_wr),
.data_b (bk_data[7:0]),
.q_b (bk_q[7:0])
);
dpram #(16) cram_h (
.clock_a (clk_cpu2x),
.address_a (cram_addr[16:1]),
.wren_a (cram_wr & cram_addr[0]),
.data_a (cart_di),
.q_a (cram_q_h),
.clock_b (clk_sys),
.address_b (bk_addr[15:0]),
.wren_b (bk_wr),
.data_b (bk_data[15:8]),
.q_b (bk_q[15:8])
);
wire downloading = cart_download;
reg bk_ena = 0;
reg new_load = 0;
reg old_downloading = 0;
reg sav_pending = 0;
wire sav_supported = (mbc_battery && (cart_ram_size > 0 || mbc2) && bk_ena);
always @(posedge clk_sys) begin
old_downloading <= downloading;
if(~old_downloading & downloading) bk_ena <= 0;
//Save file always mounted in the end of downloading state.
if(downloading && img_mounted && img_size && !img_readonly) bk_ena <= 1;
if (old_downloading & ~downloading & sav_supported)
new_load <= 1'b1;
else if (bk_state)
new_load <= 1'b0;
if (cram_wr & ~OSD_STATUS & sav_supported)
sav_pending <= 1'b1;
else if (bk_state)
sav_pending <= 1'b0;
end
wire bk_load = status[9] | new_load;
wire bk_save = status[10] | (sav_pending & OSD_STATUS & status[13]);
reg bk_loading = 0;
reg bk_state = 0;
// RAM size
wire [7:0] ram_mask_file = // 0 - no ram
(mbc2)?8'h01: // mbc2 512x4bits
(cart_ram_size == 1)?8'h03: // 1 - 2k, 1 bank sd_lba[1:0]
(cart_ram_size == 2)?8'h0F: // 2 - 8k, 1 bank sd_lba[3:0]
(cart_ram_size == 3)?8'h3F: // 3 - 32k, 4 banks sd_lba[5:0]
8'hFF; // 4 - 128k 16 banks sd_lba[7:0] 1111
always @(posedge clk_sys) begin
reg old_load = 0, old_save = 0, old_ack;
old_load <= bk_load;
old_save <= bk_save;
old_ack <= sd_ack;
if(~old_ack & sd_ack) {sd_rd, sd_wr} <= 0;
if(!bk_state) begin
if(bk_ena & ((~old_load & bk_load) | (~old_save & bk_save))) begin
bk_state <= 1;
bk_loading <= bk_load;
sd_lba <= 32'd0;
sd_rd <= bk_load;
sd_wr <= ~bk_load;
end
end else begin
if(old_ack & ~sd_ack) begin
if(sd_lba[7:0]>=ram_mask_file) begin
bk_loading <= 0;
bk_state <= 0;
end else begin
sd_lba <= sd_lba + 1'd1;
sd_rd <= bk_loading;
sd_wr <= ~bk_loading;
end
end
end
end
reg [1:0] line_cnt;
always @(posedge clk_sys_old) begin
reg old_hs;
reg old_vs;
old_vs <= video_vs;
old_hs <= video_hs;
if(old_hs & ~video_hs) line_cnt <= line_cnt + 1'd1;
if(old_vs & ~video_vs) line_cnt <= 0;
end
endmodule
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