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sd2snes/verilog/sd2snes_obc1/main.v
ikari f7e1208b06 comments, wording, cleanup, cosmetics
2021-07-28 02:19:06 +02:00

787 lines
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Verilog
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`timescale 1 ns / 1 ns
//////////////////////////////////////////////////////////////////////////////////
// Company: Rehkopf
// Engineer: Rehkopf
//
// Create Date: 01:13:46 05/09/2009
// Design Name:
// Module Name: main
// Project Name:
// Target Devices:
// Tool versions:
// Description: Master Control FSM
//
// Dependencies: address
//
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
//
//////////////////////////////////////////////////////////////////////////////////
module main(
`ifdef MK2
/* Bus 1: PSRAM, 128Mbit, 16bit, 70ns */
output [22:0] ROM_ADDR,
output ROM_CE,
input MCU_OVR,
/* debug */
output p113_out,
`endif
`ifdef MK3
input SNES_CIC_CLK,
/* Bus 1: 2x PSRAM, 64Mbit, 16bit, 70ns */
output [21:0] ROM_ADDR,
output ROM_1CE,
output ROM_2CE,
output ROM_ZZ,
/* debug */
output PM6_out,
output PN6_out,
input PT5_in,
`endif
/* input clock */
input CLKIN,
/* SNES signals */
input [23:0] SNES_ADDR_IN,
input SNES_READ_IN,
input SNES_WRITE_IN,
input SNES_ROMSEL_IN,
inout [7:0] SNES_DATA,
input SNES_CPU_CLK_IN,
input SNES_REFRESH,
output SNES_IRQ,
output SNES_DATABUS_OE,
output SNES_DATABUS_DIR,
input SNES_SYSCLK,
input [7:0] SNES_PA_IN,
input SNES_PARD_IN,
input SNES_PAWR_IN,
/* SRAM signals */
inout [15:0] ROM_DATA,
output ROM_OE,
output ROM_WE,
output ROM_BHE,
output ROM_BLE,
/* Bus 2: SRAM, 4Mbit, 8bit, 45ns */
inout [7:0] RAM_DATA,
output [18:0] RAM_ADDR,
output RAM_OE,
output RAM_WE,
/* MCU signals */
input SPI_MOSI,
inout SPI_MISO,
input SPI_SS,
input SPI_SCK,
output MCU_RDY,
output DAC_MCLK,
output DAC_LRCK,
output DAC_SDOUT,
/* SD signals */
input [3:0] SD_DAT,
inout SD_CMD,
inout SD_CLK
);
wire CLK2;
wire [7:0] spi_cmd_data;
wire [7:0] spi_param_data;
wire [7:0] spi_input_data;
wire [31:0] spi_byte_cnt;
wire [2:0] spi_bit_cnt;
wire [23:0] MCU_ADDR;
wire [2:0] MAPPER;
wire [23:0] SAVERAM_MASK;
wire [23:0] ROM_MASK;
wire [7:0] SD_DMA_SRAM_DATA;
wire [1:0] SD_DMA_TGT;
wire [10:0] SD_DMA_PARTIAL_START;
wire [10:0] SD_DMA_PARTIAL_END;
wire [10:0] dac_addr;
wire [2:0] dac_vol_select_out;
wire [8:0] dac_ptr_addr;
wire [7:0] msu_volumerq_out;
wire [7:0] msu_status_out;
wire [31:0] msu_addressrq_out;
wire [15:0] msu_trackrq_out;
wire [13:0] msu_write_addr;
wire [13:0] msu_ptr_addr;
wire [7:0] MSU_SNES_DATA_IN;
wire [7:0] MSU_SNES_DATA_OUT;
wire [5:0] msu_status_reset_bits;
wire [5:0] msu_status_set_bits;
wire [15:0] featurebits;
wire feat_cmd_unlock = featurebits[5];
wire [23:0] MAPPED_SNES_ADDR;
wire ROM_ADDR0;
wire [7:0] OBC1_SNES_DATA_IN;
wire [7:0] OBC1_SNES_DATA_OUT;
wire [13:0] DBG_msu_address;
wire DBG_msu_reg_oe_rising;
wire DBG_msu_reg_oe_falling;
wire DBG_msu_reg_we_rising;
wire [2:0] SD_DMA_DBG_clkcnt;
wire [10:0] SD_DMA_DBG_cyclecnt;
wire [8:0] snescmd_addr_mcu;
wire [7:0] snescmd_data_out_mcu;
wire [7:0] snescmd_data_in_mcu;
reg [7:0] SNES_PARDr = 8'b11111111;
reg [7:0] SNES_PAWRr = 8'b11111111;
reg [7:0] SNES_READr = 8'b11111111;
reg [7:0] SNES_WRITEr = 8'b11111111;
reg [7:0] SNES_CPU_CLKr = 8'b00000000;
reg [7:0] SNES_ROMSELr = 8'b11111111;
reg [7:0] SNES_PULSEr = 8'b11111111;
reg [23:0] SNES_ADDRr [6:0];
reg [7:0] SNES_PAr [6:0];
reg [7:0] SNES_DATAr [4:0];
reg SNES_DEADr = 1;
reg SNES_reset_strobe = 0;
reg free_strobe = 0;
wire [23:0] SNES_ADDR = (SNES_ADDRr[5] & SNES_ADDRr[4]);
wire [7:0] SNES_PA = (SNES_PAr[5] & SNES_PAr[4]);
wire [7:0] SNES_DATA_IN = (SNES_DATAr[3] & SNES_DATAr[2]);
wire SNES_PULSE_IN = SNES_READ_IN & SNES_WRITE_IN & ~SNES_CPU_CLK_IN;
wire SNES_PULSE_end = (SNES_PULSEr[6:1] == 6'b000011);
wire SNES_PARD_start = (SNES_PARDr[6:1] == 6'b111110);
wire SNES_PARD_end = (SNES_PARDr[6:1] == 6'b000001);
// Sample PAWR data earlier on CPU accesses, later on DMA accesses...
wire SNES_PAWR_start = (SNES_PAWRr[7:1] == (({SNES_ADDR[22], SNES_ADDR[15:0]} == 17'h02100) ? 7'b1110000 : 7'b1000000));
wire SNES_PAWR_end = (SNES_PAWRr[6:1] == 6'b000001);
wire SNES_RD_start = (SNES_READr[6:1] == 6'b111110);
wire SNES_RD_end = (SNES_READr[6:1] == 6'b000001);
wire SNES_WR_end = (SNES_WRITEr[6:1] == 6'b000001);
wire SNES_cycle_start = (SNES_CPU_CLKr[6:1] == 6'b000001);
wire SNES_cycle_end = (SNES_CPU_CLKr[6:1] == 6'b111110);
wire SNES_WRITE = SNES_WRITEr[2] & SNES_WRITEr[1];
wire SNES_READ = SNES_READr[2] & SNES_READr[1];
wire SNES_READ_late = SNES_READr[5] & SNES_READr[4];
wire SNES_READ_narrow = SNES_READ | SNES_READ_late;
wire SNES_CPU_CLK = SNES_CPU_CLKr[2] & SNES_CPU_CLKr[1];
wire SNES_PARD = SNES_PARDr[2] & SNES_PARDr[1];
wire SNES_PAWR = SNES_PAWRr[2] & SNES_PAWRr[1];
wire SNES_ROMSEL = (SNES_ROMSELr[5] & SNES_ROMSELr[4]);
reg [7:0] BUS_DATA;
always @(posedge CLK2) begin
if(~SNES_READ) BUS_DATA <= SNES_DATA;
else if(~SNES_WRITE) BUS_DATA <= SNES_DATA_IN;
end
wire SD_DMA_TO_ROM;
wire free_slot = (SNES_PULSE_end | free_strobe) & ~SD_DMA_TO_ROM;
wire ROM_HIT;
assign DCM_RST=0;
always @(posedge CLK2) begin
free_strobe <= 1'b0;
if(SNES_cycle_start) free_strobe <= ~ROM_HIT;
end
always @(posedge CLK2) begin
SNES_PULSEr <= {SNES_PULSEr[6:0], SNES_PULSE_IN};
SNES_PARDr <= {SNES_PARDr[6:0], SNES_PARD_IN};
SNES_PAWRr <= {SNES_PAWRr[6:0], SNES_PAWR_IN};
SNES_READr <= {SNES_READr[6:0], SNES_READ_IN};
SNES_WRITEr <= {SNES_WRITEr[6:0], SNES_WRITE_IN};
SNES_CPU_CLKr <= {SNES_CPU_CLKr[6:0], SNES_CPU_CLK_IN};
SNES_ROMSELr <= {SNES_ROMSELr[6:0], SNES_ROMSEL_IN};
SNES_ADDRr[6] <= SNES_ADDRr[5];
SNES_ADDRr[5] <= SNES_ADDRr[4];
SNES_ADDRr[4] <= SNES_ADDRr[3];
SNES_ADDRr[3] <= SNES_ADDRr[2];
SNES_ADDRr[2] <= SNES_ADDRr[1];
SNES_ADDRr[1] <= SNES_ADDRr[0];
SNES_ADDRr[0] <= SNES_ADDR_IN;
SNES_PAr[6] <= SNES_PAr[5];
SNES_PAr[5] <= SNES_PAr[4];
SNES_PAr[4] <= SNES_PAr[3];
SNES_PAr[3] <= SNES_PAr[2];
SNES_PAr[2] <= SNES_PAr[1];
SNES_PAr[1] <= SNES_PAr[0];
SNES_PAr[0] <= SNES_PA_IN;
SNES_DATAr[4] <= SNES_DATAr[3];
SNES_DATAr[3] <= SNES_DATAr[2];
SNES_DATAr[2] <= SNES_DATAr[1];
SNES_DATAr[1] <= SNES_DATAr[0];
SNES_DATAr[0] <= SNES_DATA;
end
sd_dma snes_sd_dma(
.CLK(CLK2),
.SD_DAT(SD_DAT),
.SD_CLK(SD_CLK),
.SD_DMA_EN(SD_DMA_EN),
.SD_DMA_STATUS(SD_DMA_STATUS),
.SD_DMA_SRAM_WE(SD_DMA_SRAM_WE),
.SD_DMA_SRAM_DATA(SD_DMA_SRAM_DATA),
.SD_DMA_NEXTADDR(SD_DMA_NEXTADDR),
.SD_DMA_PARTIAL(SD_DMA_PARTIAL),
.SD_DMA_PARTIAL_START(SD_DMA_PARTIAL_START),
.SD_DMA_PARTIAL_END(SD_DMA_PARTIAL_END),
.SD_DMA_START_MID_BLOCK(SD_DMA_START_MID_BLOCK),
.SD_DMA_END_MID_BLOCK(SD_DMA_END_MID_BLOCK),
.DBG_cyclecnt(SD_DMA_DBG_cyclecnt),
.DBG_clkcnt(SD_DMA_DBG_clkcnt)
);
assign SD_DMA_TO_ROM = (SD_DMA_STATUS && (SD_DMA_TGT == 2'b00));
dac snes_dac(
.clkin(CLK2),
.sysclk(SNES_SYSCLK),
.mclk_out(DAC_MCLK),
.lrck_out(DAC_LRCK),
.sdout(DAC_SDOUT),
.we(SD_DMA_TGT==2'b01 ? SD_DMA_SRAM_WE : 1'b1),
.pgm_address(dac_addr),
.pgm_data(SD_DMA_SRAM_DATA),
.DAC_STATUS(DAC_STATUS),
.volume(msu_volumerq_out),
.vol_latch(msu_volume_latch_out),
.vol_select(dac_vol_select_out),
.palmode(dac_palmode_out),
.play(dac_play),
.reset(dac_reset),
.dac_address_ext(dac_ptr_addr)
);
msu snes_msu (
.clkin(CLK2),
.enable(msu_enable),
.pgm_address(msu_write_addr),
.pgm_data(SD_DMA_SRAM_DATA),
.pgm_we(SD_DMA_TGT==2'b10 ? SD_DMA_SRAM_WE : 1'b1),
.reg_addr(SNES_ADDR[2:0]),
.reg_data_in(MSU_SNES_DATA_IN),
.reg_data_out(MSU_SNES_DATA_OUT),
.reg_oe_falling(SNES_RD_start),
.reg_oe_rising(SNES_RD_end),
.reg_we_rising(SNES_WR_end),
.status_out(msu_status_out),
.volume_out(msu_volumerq_out),
.volume_latch_out(msu_volume_latch_out),
.addr_out(msu_addressrq_out),
.track_out(msu_trackrq_out),
.status_reset_bits(msu_status_reset_bits),
.status_set_bits(msu_status_set_bits),
.status_reset_we(msu_status_reset_we),
.msu_address_ext(msu_ptr_addr),
.msu_address_ext_write(msu_addr_reset),
.DBG_msu_reg_oe_rising(DBG_msu_reg_oe_rising),
.DBG_msu_reg_oe_falling(DBG_msu_reg_oe_falling),
.DBG_msu_reg_we_rising(DBG_msu_reg_we_rising),
.DBG_msu_address(DBG_msu_address),
.DBG_msu_address_ext_write_rising(DBG_msu_address_ext_write_rising)
);
spi snes_spi(
.clk(CLK2),
.MOSI(SPI_MOSI),
.MISO(SPI_MISO),
.SSEL(SPI_SS),
.SCK(SPI_SCK),
.cmd_ready(spi_cmd_ready),
.param_ready(spi_param_ready),
.cmd_data(spi_cmd_data),
.param_data(spi_param_data),
.endmessage(spi_endmessage),
.startmessage(spi_startmessage),
.input_data(spi_input_data),
.byte_cnt(spi_byte_cnt),
.bit_cnt(spi_bit_cnt)
);
obc1 snes_obc1 (
.clk(CLK2),
.enable(obc1_enable),
.data_in(OBC1_SNES_DATA_IN),
.data_out(OBC1_SNES_DATA_OUT),
.addr_in(SNES_ADDR[12:0]),
.reg_we_rising(SNES_WR_end)
);
reg [7:0] MCU_DINr;
wire [7:0] MCU_DOUT;
wire [31:0] cheat_pgm_data;
wire [7:0] cheat_data_out;
wire [2:0] cheat_pgm_idx;
mcu_cmd snes_mcu_cmd(
.clk(CLK2),
.snes_sysclk(SNES_SYSCLK),
.cmd_ready(spi_cmd_ready),
.param_ready(spi_param_ready),
.cmd_data(spi_cmd_data),
.param_data(spi_param_data),
.mcu_mapper(MAPPER),
.mcu_write(MCU_WRITE),
.mcu_data_in(MCU_DINr),
.mcu_data_out(MCU_DOUT),
.spi_byte_cnt(spi_byte_cnt),
.spi_bit_cnt(spi_bit_cnt),
.spi_data_out(spi_input_data),
.addr_out(MCU_ADDR),
.saveram_mask_out(SAVERAM_MASK),
.rom_mask_out(ROM_MASK),
.SD_DMA_EN(SD_DMA_EN),
.SD_DMA_STATUS(SD_DMA_STATUS),
.SD_DMA_NEXTADDR(SD_DMA_NEXTADDR),
.SD_DMA_SRAM_DATA(SD_DMA_SRAM_DATA),
.SD_DMA_SRAM_WE(SD_DMA_SRAM_WE),
.SD_DMA_TGT(SD_DMA_TGT),
.SD_DMA_PARTIAL(SD_DMA_PARTIAL),
.SD_DMA_PARTIAL_START(SD_DMA_PARTIAL_START),
.SD_DMA_PARTIAL_END(SD_DMA_PARTIAL_END),
.SD_DMA_START_MID_BLOCK(SD_DMA_START_MID_BLOCK),
.SD_DMA_END_MID_BLOCK(SD_DMA_END_MID_BLOCK),
.dac_addr_out(dac_addr),
.DAC_STATUS(DAC_STATUS),
.dac_play_out(dac_play),
.dac_reset_out(dac_reset),
.dac_vol_select_out(dac_vol_select_out),
.dac_palmode_out(dac_palmode_out),
.dac_ptr_out(dac_ptr_addr),
.msu_addr_out(msu_write_addr),
.MSU_STATUS(msu_status_out),
.msu_status_reset_out(msu_status_reset_bits),
.msu_status_set_out(msu_status_set_bits),
.msu_status_reset_we(msu_status_reset_we),
.msu_volumerq(msu_volumerq_out),
.msu_addressrq(msu_addressrq_out),
.msu_trackrq(msu_trackrq_out),
.msu_ptr_out(msu_ptr_addr),
.msu_reset_out(msu_addr_reset),
.featurebits_out(featurebits),
.mcu_rrq(MCU_RRQ),
.mcu_wrq(MCU_WRQ),
.mcu_rq_rdy(MCU_RDY),
.region_out(mcu_region),
.snescmd_addr_out(snescmd_addr_mcu),
.snescmd_we_out(snescmd_we_mcu),
.snescmd_data_out(snescmd_data_out_mcu),
.snescmd_data_in(snescmd_data_in_mcu),
.cheat_pgm_idx_out(cheat_pgm_idx),
.cheat_pgm_data_out(cheat_pgm_data),
.cheat_pgm_we_out(cheat_pgm_we)
);
address snes_addr(
.CLK(CLK2),
.MAPPER(MAPPER),
.featurebits(featurebits),
.SNES_ADDR(SNES_ADDR), // requested address from SNES
.SNES_PA(SNES_PA),
.SNES_ROMSEL(SNES_ROMSEL),
.ROM_ADDR(MAPPED_SNES_ADDR), // Address to request from SRAM (active low)
.ROM_HIT(ROM_HIT),
.IS_SAVERAM(IS_SAVERAM),
.IS_ROM(IS_ROM),
.IS_WRITABLE(IS_WRITABLE),
.SAVERAM_MASK(SAVERAM_MASK),
.ROM_MASK(ROM_MASK),
//MSU-1
.msu_enable(msu_enable),
.r213f_enable(r213f_enable),
.r2100_hit(r2100_hit),
.obc1_enable(obc1_enable),
.snescmd_enable(snescmd_enable),
.nmicmd_enable(nmicmd_enable),
.return_vector_enable(return_vector_enable),
.branch1_enable(branch1_enable),
.branch2_enable(branch2_enable),
.branch3_enable(branch3_enable)
);
reg pad_latch = 0;
reg [4:0] pad_cnt = 0;
reg snes_ajr = 0;
parameter ST_IDLE = 5'b00001;
parameter ST_MCU_RD_ADDR = 5'b00010;
parameter ST_MCU_RD_END = 5'b00100;
parameter ST_MCU_WR_ADDR = 5'b01000;
parameter ST_MCU_WR_END = 5'b10000;
parameter SNES_DEAD_TIMEOUT = 17'd96000; // 1ms
parameter ROM_CYCLE_LEN = 4'd8;
reg [4:0] STATE;
initial STATE = ST_IDLE;
assign MSU_SNES_DATA_IN = BUS_DATA;
assign OBC1_SNES_DATA_IN = BUS_DATA;
cheat snes_cheat(
.clk(CLK2),
.SNES_ADDR(SNES_ADDR),
.SNES_PA(SNES_PA),
.SNES_DATA(SNES_DATA),
.SNES_reset_strobe(SNES_reset_strobe),
.SNES_cycle_start(SNES_cycle_start),
.SNES_wr_strobe(SNES_WR_end),
.SNES_rd_strobe(SNES_RD_start),
.snescmd_enable(snescmd_enable),
.nmicmd_enable(nmicmd_enable),
.return_vector_enable(return_vector_enable),
.branch1_enable(branch1_enable),
.branch2_enable(branch2_enable),
.branch3_enable(branch3_enable),
.pad_latch(pad_latch),
.snes_ajr(snes_ajr),
.pgm_idx(cheat_pgm_idx),
.pgm_we(cheat_pgm_we),
.pgm_in(cheat_pgm_data),
.data_out(cheat_data_out),
.cheat_hit(cheat_hit),
.snescmd_unlock(snescmd_unlock)
);
wire [7:0] snescmd_dout;
parameter ST_R213F_ARMED = 4'b0001;
parameter ST_R213F_WAITBUS = 4'b0010;
parameter ST_R213F_OVERRIDE = 4'b0100;
parameter ST_R213F_HOLD = 4'b1000;
reg [7:0] r213fr;
reg r213f_forceread;
reg [2:0] r213f_delay;
reg [1:0] r213f_state;
initial r213fr = 8'h55;
initial r213f_forceread = 0;
initial r213f_state = 2'b01;
initial r213f_delay = 3'b000;
reg [7:0] r2100r = 0;
reg r2100_forcewrite = 0;
reg r2100_forcewrite_pre = 0;
wire [3:0] r2100_limit = featurebits[10:7];
wire [3:0] r2100_limited = (SNES_DATA[3:0] > r2100_limit) ? r2100_limit : SNES_DATA[3:0];
wire r2100_patch = featurebits[6];
wire r2100_enable = r2100_hit & (r2100_patch | ~(&r2100_limit));
wire snoop_4200_enable = {SNES_ADDR[22], SNES_ADDR[15:0]} == 17'h04200;
wire r4016_enable = {SNES_ADDR[22], SNES_ADDR[15:0]} == 17'h04016;
always @(posedge CLK2) begin
r2100_forcewrite <= r2100_forcewrite_pre;
end
always @(posedge CLK2) begin
if(SNES_WR_end & snoop_4200_enable) begin
snes_ajr <= SNES_DATA[0];
end
end
always @(posedge CLK2) begin
if(SNES_WR_end & r4016_enable) begin
pad_latch <= 1'b1;
pad_cnt <= 5'h0;
end
if(SNES_RD_start & r4016_enable) begin
pad_cnt <= pad_cnt + 1;
if(&pad_cnt[3:0]) begin
pad_latch <= 1'b0;
end
end
end
assign SNES_DATA = (r213f_enable & ~SNES_PARD & ~r213f_forceread) ? r213fr
:(r2100_enable & ~SNES_PAWR & r2100_forcewrite) ? r2100r
:((~SNES_READ ^ (r213f_forceread & r213f_enable & ~SNES_PARD))
& ~(r2100_enable & ~SNES_PAWR & ~r2100_forcewrite & ~IS_ROM & ~IS_WRITABLE))
? (msu_enable ? MSU_SNES_DATA_OUT
:obc1_enable ? OBC1_SNES_DATA_OUT
:(cheat_hit & ~feat_cmd_unlock) ? cheat_data_out
:((snescmd_unlock | feat_cmd_unlock) & snescmd_enable) ? snescmd_dout
:(ROM_ADDR0 ? ROM_DATA[7:0] : ROM_DATA[15:8])) : 8'bZ;
reg [3:0] ST_MEM_DELAYr;
reg MCU_RD_PENDr = 0;
reg MCU_WR_PENDr = 0;
reg [23:0] ROM_ADDRr;
reg RQ_MCU_RDYr;
initial RQ_MCU_RDYr = 1'b1;
assign MCU_RDY = RQ_MCU_RDYr;
wire MCU_WE_HIT = |(STATE & ST_MCU_WR_ADDR);
wire MCU_WR_HIT = |(STATE & (ST_MCU_WR_ADDR | ST_MCU_WR_END));
wire MCU_RD_HIT = |(STATE & (ST_MCU_RD_ADDR | ST_MCU_RD_END));
wire MCU_HIT = MCU_WR_HIT | MCU_RD_HIT;
`ifdef MK2
my_dcm snes_dcm(
.CLKIN(CLKIN),
.CLKFX(CLK2),
.LOCKED(DCM_LOCKED),
.RST(DCM_RST)
);
assign ROM_ADDR = (SD_DMA_TO_ROM) ? MCU_ADDR[23:1] : MCU_HIT ? ROM_ADDRr[23:1] : MAPPED_SNES_ADDR[23:1];
assign ROM_ADDR0 = (SD_DMA_TO_ROM) ? MCU_ADDR[0] : MCU_HIT ? ROM_ADDRr[0] : MAPPED_SNES_ADDR[0];
assign ROM_CE = 1'b0;
assign p113_out = 1'b0;
snescmd_buf snescmd (
.clka(CLK2), // input clka
.wea(SNES_WR_end & ((snescmd_unlock | feat_cmd_unlock) & snescmd_enable)), // input [0 : 0] wea
.addra(SNES_ADDR[8:0]), // input [8 : 0] addra
.dina(SNES_DATA), // input [7 : 0] dina
.douta(snescmd_dout), // output [7 : 0] douta
.clkb(CLK2), // input clkb
.web(snescmd_we_mcu), // input [0 : 0] web
.addrb(snescmd_addr_mcu), // input [8 : 0] addrb
.dinb(snescmd_data_out_mcu), // input [7 : 0] dinb
.doutb(snescmd_data_in_mcu) // output [7 : 0] doutb
);
`endif
`ifdef MK3
pll snes_pll(
.inclk0(CLKIN),
.c0(CLK2),
.locked(DCM_LOCKED),
.areset(DCM_RST)
);
wire ROM_ADDR22;
assign ROM_ADDR22 = (SD_DMA_TO_ROM) ? MCU_ADDR[1] : MCU_HIT ? ROM_ADDRr[1] : MAPPED_SNES_ADDR[1];
assign ROM_ADDR = (SD_DMA_TO_ROM) ? MCU_ADDR[23:2] : MCU_HIT ? ROM_ADDRr[23:2] : MAPPED_SNES_ADDR[23:2];
assign ROM_ADDR0 = (SD_DMA_TO_ROM) ? MCU_ADDR[0] : MCU_HIT ? ROM_ADDRr[0] : MAPPED_SNES_ADDR[0];
assign ROM_ZZ = 1'b1;
assign ROM_1CE = ROM_ADDR22;
assign ROM_2CE = ~ROM_ADDR22;
snescmd_buf snescmd (
.clock(CLK2), // input clka
.wren_a(SNES_WR_end & ((snescmd_unlock | feat_cmd_unlock) & snescmd_enable)), // input [0 : 0] wea
.address_a(SNES_ADDR[8:0]), // input [8 : 0] addra
.data_a(SNES_DATA), // input [7 : 0] dina
.q_a(snescmd_dout), // output [7 : 0] douta
.wren_b(snescmd_we_mcu), // input [0 : 0] web
.address_b(snescmd_addr_mcu), // input [8 : 0] addrb
.data_b(snescmd_data_out_mcu), // input [7 : 0] dinb
.q_b(snescmd_data_in_mcu) // output [7 : 0] doutb
);
`endif
// OE always active. Overridden by WE when needed.
assign ROM_OE = 1'b0;
reg[17:0] SNES_DEAD_CNTr;
initial SNES_DEAD_CNTr = 0;
// MCU r/w request
always @(posedge CLK2) begin
if(MCU_RRQ) begin
MCU_RD_PENDr <= 1'b1;
RQ_MCU_RDYr <= 1'b0;
ROM_ADDRr <= MCU_ADDR;
end else if(MCU_WRQ) begin
MCU_WR_PENDr <= 1'b1;
RQ_MCU_RDYr <= 1'b0;
ROM_ADDRr <= MCU_ADDR;
end else if(STATE & (ST_MCU_RD_END | ST_MCU_WR_END)) begin
MCU_RD_PENDr <= 1'b0;
MCU_WR_PENDr <= 1'b0;
RQ_MCU_RDYr <= 1'b1;
end
end
always @(posedge CLK2) begin
if(~SNES_CPU_CLKr[1]) SNES_DEAD_CNTr <= SNES_DEAD_CNTr + 1;
else SNES_DEAD_CNTr <= 17'h0;
end
always @(posedge CLK2) begin
SNES_reset_strobe <= 1'b0;
if(SNES_CPU_CLKr[1]) begin
SNES_DEADr <= 1'b0;
if(SNES_DEADr) SNES_reset_strobe <= 1'b1;
end
else if(SNES_DEAD_CNTr > SNES_DEAD_TIMEOUT) SNES_DEADr <= 1'b1;
end
always @(posedge CLK2) begin
if(SNES_DEADr & SNES_CPU_CLKr[1]) STATE <= ST_IDLE; // interrupt+restart an ongoing MCU access when the SNES comes alive
else
case(STATE)
ST_IDLE: begin
STATE <= ST_IDLE;
if(free_slot | SNES_DEADr) begin
if(MCU_RD_PENDr) begin
STATE <= ST_MCU_RD_ADDR;
ST_MEM_DELAYr <= ROM_CYCLE_LEN;
end else if(MCU_WR_PENDr) begin
STATE <= ST_MCU_WR_ADDR;
ST_MEM_DELAYr <= ROM_CYCLE_LEN;
end
end
end
ST_MCU_RD_ADDR: begin
STATE <= ST_MCU_RD_ADDR;
ST_MEM_DELAYr <= ST_MEM_DELAYr - 1;
if(ST_MEM_DELAYr == 0) STATE <= ST_MCU_RD_END;
MCU_DINr <= (ROM_ADDR0 ? ROM_DATA[7:0] : ROM_DATA[15:8]);
end
ST_MCU_WR_ADDR: begin
STATE <= ST_MCU_WR_ADDR;
ST_MEM_DELAYr <= ST_MEM_DELAYr - 1;
if(ST_MEM_DELAYr == 0) STATE <= ST_MCU_WR_END;
end
ST_MCU_RD_END, ST_MCU_WR_END: begin
STATE <= ST_IDLE;
end
endcase
end
/***********************
* R213F read patching *
***********************/
always @(posedge CLK2) begin
case(r213f_state)
ST_R213F_HOLD: begin
r213f_state <= ST_R213F_HOLD;
if(SNES_PULSE_end) begin
r213f_forceread <= 1'b1;
r213f_state <= ST_R213F_ARMED;
end
end
ST_R213F_ARMED: begin
r213f_state <= ST_R213F_ARMED;
if(SNES_PARD_start & r213f_enable) begin
r213f_delay <= 3'b001;
r213f_state <= ST_R213F_WAITBUS;
end
end
ST_R213F_WAITBUS: begin
r213f_state <= ST_R213F_WAITBUS;
r213f_delay <= r213f_delay - 1;
if(r213f_delay == 3'b000) begin
r213f_state <= ST_R213F_OVERRIDE;
r213fr <= {SNES_DATA[7:5], mcu_region, SNES_DATA[3:0]};
end
end
ST_R213F_OVERRIDE: begin
r213f_state <= ST_R213F_HOLD;
r213f_forceread <= 1'b0;
end
endcase
end
/*********************************
* R2100 patching (experimental) *
*********************************/
reg [3:0] r2100_bright = 0;
reg [3:0] r2100_bright_orig = 0;
always @(posedge CLK2) begin
if(SNES_PULSE_end) r2100_forcewrite_pre <= 1'b0;
else if(SNES_PAWR_start & r2100_hit) begin
if(r2100_patch & SNES_DATA[7]) begin
// keep previous brightness during forced blanking so there is no DAC step
r2100_forcewrite_pre <= 1'b1;
r2100r <= {SNES_DATA[7], 3'b010, r2100_bright}; // 0xAx
end else if (r2100_patch && SNES_DATA == 8'h00 && r2100r[7]) begin
// extend forced blanking when game goes from blanking to brightness 0 (Star Fox top of screen)
r2100_forcewrite_pre <= 1'b1;
r2100r <= {1'b1, 3'b111, r2100_bright}; // 0xFx
end else if (r2100_patch && SNES_DATA[3:0] < 4'h8 && r2100_bright_orig > 4'hd) begin
// substitute big brightness changes with brightness 0 (so it is visible on 1CHIP)
r2100_forcewrite_pre <= 1'b1;
r2100r <= {SNES_DATA[7], 3'b011, 4'h0}; // 0x3x / 0xBx(!)
end else if (r2100_patch | ~(&r2100_limit)) begin
// save brightness, limit brightness
r2100_bright <= r2100_limited;
r2100_bright_orig <= SNES_DATA[3:0];
if (~(&r2100_limit) && SNES_DATA[3:0] > r2100_limit) begin
r2100_forcewrite_pre <= 1'b1;
r2100r <= {SNES_DATA[7], 3'b100, r2100_limited}; // 0x4x / 0xCx
end
end
end
end
reg MCU_WRITE_1;
always @(posedge CLK2) begin
MCU_WRITE_1<= MCU_WRITE;
end
assign ROM_DATA[7:0] = ROM_ADDR0
?(SD_DMA_TO_ROM ? (!MCU_WRITE_1 ? MCU_DOUT : 8'bZ)
: (ROM_HIT & ~SNES_WRITE) ? SNES_DATA
: MCU_WR_HIT ? MCU_DOUT : 8'bZ
)
:8'bZ;
assign ROM_DATA[15:8] = ROM_ADDR0 ? 8'bZ
:(SD_DMA_TO_ROM ? (!MCU_WRITE_1 ? MCU_DOUT : 8'bZ)
: (ROM_HIT & ~SNES_WRITE) ? SNES_DATA
: MCU_WR_HIT ? MCU_DOUT
: 8'bZ
);
assign ROM_WE = SD_DMA_TO_ROM
?MCU_WRITE
: (ROM_HIT & IS_WRITABLE & SNES_CPU_CLK) ? SNES_WRITE
: MCU_WE_HIT ? 1'b0
: 1'b1;
assign ROM_BHE = ROM_ADDR0;
assign ROM_BLE = ~ROM_ADDR0;
assign SNES_DATABUS_OE = obc1_enable & ~(SNES_READ_narrow & SNES_WRITE) ? 1'b0 :
msu_enable & ~(SNES_READ_narrow & SNES_WRITE) ? 1'b0 :
snescmd_enable & ~(SNES_READ_narrow & SNES_WRITE) ? ~(snescmd_unlock | feat_cmd_unlock) :
(r213f_enable & !SNES_PARD) ? 1'b0 :
(r2100_enable & ~SNES_PAWR) ? 1'b0 :
snoop_4200_enable ? SNES_WRITE
: ((IS_ROM & SNES_ROMSEL)
|(!IS_ROM & !IS_SAVERAM & !IS_WRITABLE)
|(SNES_READ_narrow & SNES_WRITE)
);
assign SNES_DATABUS_DIR = (~SNES_READ | (~SNES_PARD & (r213f_enable)))
? (1'b1 ^ (r213f_forceread & r213f_enable & ~SNES_PARD)
^ (r2100_enable & ~SNES_PAWR & ~r2100_forcewrite & ~IS_ROM & ~IS_WRITABLE))
: ((~SNES_PAWR & r2100_enable) ? r2100_forcewrite
: 1'b0);
assign SNES_IRQ = 1'b0;
endmodule
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