FPGA: fix BS-X mapping, S-RTC interface

verilog/sd2snes/address.v

@@ -36,6 +36,7 @@ module address(
     input [23:0] ROM_MASK,
 	 input use_msu,
 	 output msu_enable,
+	 output srtc_enable,
     output use_bsx,
 	 input [14:0] bsx_regs
     );
@@ -126,13 +127,13 @@ assign SRAM_ADDR_FULL = (MODE) ? MCU_ADDR
                                           : ({1'b0, !SNES_ADDR[23], SNES_ADDR[21:0]} & ROM_MASK))
                             :(MAPPER == 3'b011) ?
                               (IS_SAVERAM ? 24'hE00000 + {SNES_ADDR[18:16], SNES_ADDR[11:0]}
-                                          : IS_WRITABLE ? (24'h400000 + (SNES_ADDR & 24'h07FFFF))
+                                          : IS_WRITABLE ? (24'h400000 + (SNES_ADDR & 24'h0FFFFF /*7ffff*/))
                                                         : ((bsx_regs[7] && SNES_ADDR[23:21] == 3'b000)
                                                            |(bsx_regs[8] && SNES_ADDR[23:21] == 3'b100))
                                                             ? (24'h800000 + ({1'b0, SNES_ADDR[23:16], SNES_ADDR[14:0]} & 24'h0FFFFF))
                                                             : ((bsx_regs[1] ? 24'h400000 : 24'h000000)
-                                                               + bsx_regs[2] ? ({2'b00, SNES_ADDR[21:0]} & (ROM_MASK >> bsx_regs[1]))
+                                                               + bsx_regs[2] ? ({2'b00, SNES_ADDR[21:0]} & (ROM_MASK /* >> bsx_regs[1] */))
-                                                                             : ({1'b0, SNES_ADDR[23:16], SNES_ADDR[14:0]} & (ROM_MASK >> bsx_regs[1]))))
+                                                                             : ({1'b0, SNES_ADDR[23:16], SNES_ADDR[14:0]} & (ROM_MASK /* >> bsx_regs[1] */))))
                             :(MAPPER == 3'b110) ?
                               (IS_SAVERAM ? 24'hE00000 + ((SNES_ADDR[14:0] - 15'h6000) & SAVERAM_MASK)
                                           : (SNES_ADDR[15] ? ({1'b0, SNES_ADDR[23:16], SNES_ADDR[14:0]})
@@ -151,4 +152,6 @@ assign ROM_ADDR0 = SRAM_ADDR_FULL[0];
 assign msu_enable = (!SNES_ADDR[22] && ((SNES_ADDR[15:0] & 16'hfff8) == 16'h2000));
 assign use_bsx = (MAPPER == 3'b011);
 
+assign srtc_enable = (!SNES_ADDR[22] && ((SNES_ADDR[15:0] & 16'hfffe) == 16'h2800));
+
 endmodule

verilog/sd2snes/clk_test.v

@@ -39,7 +39,7 @@ always @(posedge clk) sysclk_sreg <= {sysclk_sreg[0], sysclk};
 wire sysclk_rising = (sysclk_sreg == 2'b01);
 
 always @(posedge clk) begin
-  if(sysclk_counter < 92000000) begin
+  if(sysclk_counter < 96000000) begin
     sysclk_counter <= sysclk_counter + 1;
     if(sysclk_rising) sysclk_value <= sysclk_value + 1;
   end else begin

verilog/sd2snes/data.v

@@ -39,8 +39,11 @@ module data(
 		input [7:0] MSU_DATA_OUT,
 		output [7:0] BSX_DATA_IN,
 		input [7:0] BSX_DATA_OUT,
+		output [7:0] SRTC_DATA_IN,
+		input [7:0] SRTC_DATA_OUT,
 		input msu_enable,
-		input bsx_data_ovr
+		input bsx_data_ovr,
+		input srtc_enable
     );
 
 reg [7:0] SNES_IN_MEM;
@@ -52,9 +55,11 @@ wire [7:0] FROM_ROM_BYTE;
 
 assign MSU_DATA_IN = SNES_DATA;
 assign BSX_DATA_IN = SNES_DATA;
+assign SRTC_DATA_IN = SNES_DATA;
 
 assign SNES_DATA = SNES_READ ? 8'bZ : (!MCU_OVR ? 8'h00 : (msu_enable ? MSU_DATA_OUT : 
-                                                           bsx_data_ovr ? BSX_DATA_OUT : SNES_OUT_MEM));
+                                                           bsx_data_ovr ? BSX_DATA_OUT : 
+																			  srtc_enable ? SRTC_DATA_OUT : SNES_OUT_MEM));
 
 assign FROM_ROM_BYTE = (ROM_ADDR0 ? ROM_DATA[7:0] : ROM_DATA[15:8]);
 

verilog/sd2snes/main.ucf

@@ -1,5 +1,5 @@
 NET "CLKIN" TNM_NET = "CLKIN";
-TIMESPEC TS_CLKIN = PERIOD "CLKIN" 23 MHz HIGH 50 %;
+TIMESPEC TS_CLKIN = PERIOD "CLKIN" 24 MHz HIGH 50 %;
 //TIMESPEC TS_CLKIN = PERIOD "CLKIN" 21.5 MHz HIGH 50 %;
 NET "SNES_CS" IOSTANDARD = LVCMOS33;
 NET "SNES_READ" IOSTANDARD = LVCMOS33;
@@ -416,7 +416,7 @@ NET "SNES_ADDR[9]" IOSTANDARD = LVCMOS33;
 NET "SNES_ADDR[9]" DRIVE = 8;
 
 
-NET "SNES_CPU_CLK" LOC = P94;
+NET "SNES_CPU_CLK" LOC = P95;
 NET "SNES_CS" LOC = P116;
 NET "SNES_DATABUS_DIR" LOC = P111;
 NET "SNES_DATABUS_OE" LOC = P109;
@@ -443,7 +443,7 @@ NET "SNES_DATA[7]" DRIVE = 8;
 NET "SNES_IRQ" LOC = P114;
 NET "SNES_READ" LOC = P115;
 NET "SNES_REFRESH" LOC = P155;
-NET "SNES_WRITE" LOC = P95;
+NET "SNES_WRITE" LOC = P94;
 
 NET "SPI_MISO" LOC = P72;
 

verilog/sd2snes/main.v

@@ -114,8 +114,9 @@ wire [7:0] bsx_regs_set_bits;
 
 wire [59:0] rtc_data;
 wire [59:0] rtc_data_in;
-wire [7:0] RTC_SNES_DATA_IN;
+wire [59:0] srtc_rtc_data_out;
-wire [7:0] RTC_SNES_DATA_OUT;
+wire [7:0] SRTC_SNES_DATA_IN;
+wire [7:0] SRTC_SNES_DATA_OUT;
 
 //wire SD_DMA_EN; //SPI_DMA_CTRL;
 
@@ -148,11 +149,28 @@ dac snes_dac(.clkin(CLK2),
 							  .reset(dac_reset)
 );
 
+srtc snes_srtc (
+    .clkin(CLK2),
+    /*XXX*/.reg_addr(srtc_reg_addr), 
+    .addr_in(SNES_ADDR[0]), 
+    .data_in(SRTC_SNES_DATA_IN), 
+    .data_out(SRTC_SNES_DATA_OUT), 
+    .rtc_data_in(rtc_data),
+    .reg_we(SNES_WRITE), 
+    .reg_oe(SNES_READ),
+	 .enable(srtc_enable),
+	 .rtc_data_out(srtc_rtc_data_out),
+	 .rtc_we(srtc_rtc_we),
+	 .reset(srtc_reset)
+    );
+	 
 rtc snes_rtc (
     .clkin(CLKIN), 
     .rtc_data(rtc_data),
 	 .rtc_data_in(rtc_data_in),
-	 .pgm_we(rtc_pgm_we)
+	 .pgm_we(rtc_pgm_we),
+	 .rtc_data_in1(srtc_rtc_data_out),
+	 .we1(srtc_rtc_we)
     );
 	 
 msu snes_msu (
@@ -260,7 +278,8 @@ mcu_cmd snes_mcu_cmd(
 	 .bsx_regs_reset_out(bsx_regs_reset_bits),
 	 .bsx_regs_reset_we(bsx_regs_reset_we),
 	 .rtc_data_out(rtc_data_in),
-	 .rtc_pgm_we(rtc_pgm_we)
+	 .rtc_pgm_we(rtc_pgm_we),
+	 .srtc_reset(srtc_reset)
 );
 
 // dcm1: dfs 4x
@@ -368,7 +387,9 @@ address snes_addr(
 	 .msu_enable(msu_enable),
 	 //BS-X
 	 .use_bsx(use_bsx),
-	 .bsx_regs(bsx_regs)
+	 .bsx_regs(bsx_regs),
+	 //SRTC
+	 .srtc_enable(srtc_enable)
     );
 
 wire SNES_READ_CYCLEw;
@@ -396,8 +417,11 @@ data snes_data(.CLK(CLK2),
 		.MSU_DATA_OUT(MSU_SNES_DATA_OUT),
 		.BSX_DATA_IN(BSX_SNES_DATA_IN),
 		.BSX_DATA_OUT(BSX_SNES_DATA_OUT),
+		.SRTC_DATA_IN(SRTC_SNES_DATA_IN),
+		.SRTC_DATA_OUT(SRTC_SNES_DATA_OUT),
 		.msu_enable(msu_enable),
-		.bsx_data_ovr(bsx_data_ovr)
+		.bsx_data_ovr(bsx_data_ovr),
+		.srtc_enable(srtc_enable)
       );
       
 parameter MODE_SNES = 1'b0;
@@ -515,6 +539,7 @@ always @(posedge CLK2) begin
        end else begin
            case (STATE)
               STATE_0: begin
+                 SNES_WRITE_CYCLE <= SNES_WRITE;
                  STATE <= STATE_1; STATEIDX <= 11;
               end
               STATE_1: begin
@@ -634,7 +659,8 @@ assign ROM_BLE = !ROM_WE ? !ROM_ADDR0 : 1'b0;
 
 //assign SNES_DATABUS_OE = (!IS_SAVERAM & SNES_CS) | (SNES_READ & SNES_WRITE);
 assign SNES_DATABUS_OE = msu_enable ? 1'b0 :
-                         bsx_data_ovr ? 1'b0 : ((IS_ROM & SNES_CS) | (!IS_ROM & !IS_SAVERAM & !IS_WRITABLE & !IS_FLASHWR) | (SNES_READ & SNES_WRITE));
+                         bsx_data_ovr ? 1'b0 : 
+								 srtc_enable ? 1'b0 : ((IS_ROM & SNES_CS) | (!IS_ROM & !IS_SAVERAM & !IS_WRITABLE & !IS_FLASHWR) | (SNES_READ & SNES_WRITE));
 assign SNES_DATABUS_DIR = !SNES_READ ? 1'b1 : 1'b0;
 
 assign SNES_DATA_TO_MEM = SNES_DATA_TO_MEM_ARRAY[SNES_WRITE_CYCLE][STATEIDX];

verilog/sd2snes/mcu_cmd.v

@@ -80,6 +80,9 @@ module mcu_cmd(
 	 output [55:0] rtc_data_out,
 	 output rtc_pgm_we,
 	 
+	 // S-RTC
+	 output srtc_reset,
+	 
 	 // SNES sync/clk
  	 input snes_sysclk	 
     );
@@ -118,6 +121,8 @@ reg bsx_regs_reset_we_buf;
 reg [55:0] rtc_data_out_buf;
 reg rtc_pgm_we_buf;
 
+reg srtc_reset_buf;
+
 reg [31:0] SNES_SYSCLK_FREQ_BUF;
 
 reg [7:0] MCU_DATA_OUT_BUF;
@@ -332,7 +337,15 @@ always @(posedge clk) begin
 					32'h4:
 						bsx_regs_reset_we_buf <= 1'b0;
 				endcase
-				
+			8'he7:
+				case (spi_byte_cnt)
+					32'h2: begin
+					   srtc_reset_buf <= 1'b1;
+					end
+					32'h3: begin
+					   srtc_reset_buf <= 1'b0;
+					end
+				endcase
       endcase
    end
    if (SD_DMA_NEXTADDR | (mcu_nextaddr & (cmd_data[7:5] == 3'h4) && (cmd_data[3]) && (spi_byte_cnt > (32'h1+cmd_data[4])))) begin
@@ -447,6 +460,8 @@ assign bsx_regs_set_out = bsx_regs_set_out_buf;
 assign rtc_data_out = rtc_data_out_buf;
 assign rtc_pgm_we = rtc_pgm_we_buf;
 
+assign srtc_reset = srtc_reset_buf;
+
 assign mcu_data_out = SD_DMA_STATUS ? SD_DMA_SRAM_DATA : MCU_DATA_OUT_BUF;
 assign mcu_mapper = MAPPER_BUF;
 assign mcu_sram_size = SRAM_SIZE_BUF;

verilog/sd2snes/rtc.v

@@ -22,6 +22,8 @@ module rtc (
     input clkin,
 	 input pgm_we,
 	 input [59:0] rtc_data_in,
+	 input we1,
+	 input [59:0] rtc_data_in1,
     output [59:0] rtc_data
     );
 
@@ -32,11 +34,15 @@ reg [1:0] pgm_we_sreg;
 always @(posedge clkin) pgm_we_sreg <= {pgm_we_sreg[0], pgm_we};
 wire pgm_we_rising = (pgm_we_sreg[1:0] == 2'b01);
 
+reg [2:0] we1_sreg;
+always @(posedge clkin) we1_sreg <= {we1_sreg[1:0], we1};
+wire we1_rising = (we1_sreg[2:1] == 2'b01);
+
 reg [31:0] tick_cnt;
 
 always @(posedge clkin) begin
   tick_cnt <= tick_cnt + 1;
-  if(tick_cnt == 23000000) tick_cnt <= 0;
+  if((tick_cnt == 24000000) || pgm_we_rising) tick_cnt <= 0;
 end
 
 assign rtc_data = rtc_data_out_r;
@@ -97,7 +103,7 @@ initial begin
   dom1[10] <= 0; dom10[10] <= 3;
   dom1[11] <= 1; dom10[11] <= 3;  
   month <= 0;
-  rtc_data_r <= 60'h019900101000000;
+  rtc_data_r <= 60'h220110301000000;
   tick_cnt <= 0;
 end
 
@@ -163,6 +169,8 @@ end
 always @(posedge clkin) begin
   if(pgm_we_rising) begin
     rtc_data_r <= rtc_data_in;
+  end else if (we1_rising) begin
+    rtc_data_r <= rtc_data_in1;
   end else begin
     case(rtc_state)
 		  STATE_SEC1: begin

verilog/sd2snes/sd2snes.xise

@@ -113,7 +113,7 @@
     <property xil_pn:name="Add I/O Buffers" xil_pn:value="true" xil_pn:valueState="default"/>
     <property xil_pn:name="Add I/O Pads" xil_pn:value="true" xil_pn:valueState="default"/>
     <property xil_pn:name="Advanced FSM Optimization" xil_pn:value="true" xil_pn:valueState="default"/>
-    <property xil_pn:name="Allow Logic Optimization Across Hierarchy" xil_pn:value="false" xil_pn:valueState="default"/>
+    <property xil_pn:name="Allow Logic Optimization Across Hierarchy" xil_pn:value="true" xil_pn:valueState="non-default"/>
     <property xil_pn:name="Allow SelectMAP Pins to Persist" xil_pn:value="false" xil_pn:valueState="default"/>
     <property xil_pn:name="Allow Unexpanded Blocks" xil_pn:value="false" xil_pn:valueState="default"/>
     <property xil_pn:name="Allow Unmatched LOC Constraints" xil_pn:value="false" xil_pn:valueState="default"/>
@@ -123,7 +123,7 @@
     <property xil_pn:name="Auto Constrain" xil_pn:value="true" xil_pn:valueState="default"/>
     <property xil_pn:name="Auto Implementation Compile Order" xil_pn:value="true" xil_pn:valueState="default"/>
     <property xil_pn:name="Auto Implementation Top" xil_pn:value="true" xil_pn:valueState="default"/>
-    <property xil_pn:name="Automatic BRAM Packing" xil_pn:value="false" xil_pn:valueState="default"/>
+    <property xil_pn:name="Automatic BRAM Packing" xil_pn:value="true" xil_pn:valueState="non-default"/>
     <property xil_pn:name="Automatically Insert glbl Module in the Netlist" xil_pn:value="true" xil_pn:valueState="default"/>
     <property xil_pn:name="Automatically Run Generate Target PROM/ACE File" xil_pn:value="false" xil_pn:valueState="default"/>
     <property xil_pn:name="BRAM Utilization Ratio" xil_pn:value="100" xil_pn:valueState="default"/>
@@ -216,7 +216,7 @@
     <property xil_pn:name="Generate Constraints Interaction Report Post Trace" xil_pn:value="false" xil_pn:valueState="default"/>
     <property xil_pn:name="Generate Datasheet Section" xil_pn:value="true" xil_pn:valueState="default"/>
     <property xil_pn:name="Generate Datasheet Section Post Trace" xil_pn:value="true" xil_pn:valueState="default"/>
-    <property xil_pn:name="Generate Detailed MAP Report" xil_pn:value="false" xil_pn:valueState="default"/>
+    <property xil_pn:name="Generate Detailed MAP Report" xil_pn:value="true" xil_pn:valueState="non-default"/>
     <property xil_pn:name="Generate Detailed Package Parasitics" xil_pn:value="false" xil_pn:valueState="default"/>
     <property xil_pn:name="Generate Multiple Hierarchical Netlist Files" xil_pn:value="false" xil_pn:valueState="default"/>
     <property xil_pn:name="Generate Post-Place &amp; Route Power Report" xil_pn:value="false" xil_pn:valueState="default"/>
@@ -267,7 +267,7 @@
     <property xil_pn:name="Key 5 (Hex String)" xil_pn:value="" xil_pn:valueState="default"/>
     <property xil_pn:name="Language" xil_pn:value="VHDL" xil_pn:valueState="default"/>
     <property xil_pn:name="Last Applied Goal" xil_pn:value="Timing Performance" xil_pn:valueState="non-default"/>
-    <property xil_pn:name="Last Applied Strategy" xil_pn:value="Performance with IOB Packing;/mnt/store/bin/Xilinx/12.3/ISE_DS/ISE/spartan3/data/spartan3_performance_with_iobpacking.xds" xil_pn:valueState="non-default"/>
+    <property xil_pn:name="Last Applied Strategy" xil_pn:value="Performance without IOB Packing;/mnt/store/bin/Xilinx/12.3/ISE_DS/ISE/spartan3/data/spartan3_performance_without_iobpacking.xds" xil_pn:valueState="non-default"/>
     <property xil_pn:name="Last Unlock Status" xil_pn:value="false" xil_pn:valueState="default"/>
     <property xil_pn:name="Library for Verilog Sources" xil_pn:value="" xil_pn:valueState="default"/>
     <property xil_pn:name="List window" xil_pn:value="false" xil_pn:valueState="default"/>
@@ -309,7 +309,7 @@
     <property xil_pn:name="Optimization Effort" xil_pn:value="High" xil_pn:valueState="non-default" xil_pn:x_locked="true"/>
     <property xil_pn:name="Optimization Goal" xil_pn:value="Speed" xil_pn:valueState="default" xil_pn:x_locked="true"/>
     <property xil_pn:name="Optimization Strategy (Cover Mode)" xil_pn:value="Speed" xil_pn:valueState="non-default"/>
-    <property xil_pn:name="Optimize Instantiated Primitives" xil_pn:value="false" xil_pn:valueState="default"/>
+    <property xil_pn:name="Optimize Instantiated Primitives" xil_pn:value="true" xil_pn:valueState="non-default"/>
     <property xil_pn:name="Other Bitgen Command Line Options" xil_pn:value="" xil_pn:valueState="default"/>
     <property xil_pn:name="Other Compiler Options" xil_pn:value="" xil_pn:valueState="default"/>
     <property xil_pn:name="Other Compiler Options Fit" xil_pn:value="" xil_pn:valueState="default"/>
@@ -337,8 +337,8 @@
     <property xil_pn:name="Output File Name" xil_pn:value="main" xil_pn:valueState="default"/>
     <property xil_pn:name="Overwrite Compiled Libraries" xil_pn:value="false" xil_pn:valueState="default"/>
     <property xil_pn:name="Overwrite Existing Symbol" xil_pn:value="false" xil_pn:valueState="default"/>
-    <property xil_pn:name="Pack I/O Registers into IOBs" xil_pn:value="Yes" xil_pn:valueState="non-default" xil_pn:x_locked="true"/>
+    <property xil_pn:name="Pack I/O Registers into IOBs" xil_pn:value="No" xil_pn:valueState="non-default" xil_pn:x_locked="true"/>
-    <property xil_pn:name="Pack I/O Registers/Latches into IOBs" xil_pn:value="For Inputs and Outputs" xil_pn:valueState="non-default" xil_pn:x_locked="true"/>
+    <property xil_pn:name="Pack I/O Registers/Latches into IOBs" xil_pn:value="Off" xil_pn:valueState="default" xil_pn:x_locked="true"/>
     <property xil_pn:name="Package" xil_pn:value="pq208" xil_pn:valueState="default"/>
     <property xil_pn:name="Parallel Case" xil_pn:value="false" xil_pn:valueState="default"/>
     <property xil_pn:name="Perform Advanced Analysis" xil_pn:value="false" xil_pn:valueState="default"/>
@@ -372,7 +372,7 @@
     <property xil_pn:name="Read Cores" xil_pn:value="true" xil_pn:valueState="default"/>
     <property xil_pn:name="Regenerate Core" xil_pn:value="Under Current Project Setting" xil_pn:valueState="default"/>
     <property xil_pn:name="Register Balancing" xil_pn:value="Yes" xil_pn:valueState="non-default" xil_pn:x_locked="true"/>
-    <property xil_pn:name="Register Duplication" xil_pn:value="Off" xil_pn:valueState="default"/>
+    <property xil_pn:name="Register Duplication" xil_pn:value="On" xil_pn:valueState="non-default"/>
     <property xil_pn:name="Register Duplication Xst" xil_pn:value="true" xil_pn:valueState="default"/>
     <property xil_pn:name="Release Set/Reset (Output Events)" xil_pn:value="Default (6)" xil_pn:valueState="default"/>
     <property xil_pn:name="Release Write Enable (Output Events)" xil_pn:value="Default (6)" xil_pn:valueState="default"/>
@@ -395,7 +395,7 @@
     <property xil_pn:name="Report Unconstrained Paths Post Trace" xil_pn:value="" xil_pn:valueState="default"/>
     <property xil_pn:name="Reset DCM if SHUTDOWN &amp; AGHIGH performed" xil_pn:value="false" xil_pn:valueState="default"/>
     <property xil_pn:name="Reset On Configuration Pulse Width" xil_pn:value="100" xil_pn:valueState="default"/>
-    <property xil_pn:name="Resource Sharing" xil_pn:value="true" xil_pn:valueState="default"/>
+    <property xil_pn:name="Resource Sharing" xil_pn:value="false" xil_pn:valueState="non-default"/>
     <property xil_pn:name="Resource Sharing Precision" xil_pn:value="true" xil_pn:valueState="default"/>
     <property xil_pn:name="Resource Sharing Synthesis" xil_pn:value="true" xil_pn:valueState="default"/>
     <property xil_pn:name="Retain Hierarchy" xil_pn:value="true" xil_pn:valueState="default"/>
@@ -487,7 +487,7 @@
     <property xil_pn:name="Use Synchronous Reset" xil_pn:value="Yes" xil_pn:valueState="default"/>
     <property xil_pn:name="Use Synchronous Set" xil_pn:value="Yes" xil_pn:valueState="default"/>
     <property xil_pn:name="Use Synthesis Constraints File" xil_pn:value="true" xil_pn:valueState="default"/>
-    <property xil_pn:name="User Browsed Strategy Files" xil_pn:value="/mnt/store/bin/Xilinx/12.3/ISE_DS/ISE/data/default.xds" xil_pn:valueState="non-default"/>
+    <property xil_pn:name="User Browsed Strategy Files" xil_pn:value="/mnt/store/bin/Xilinx/12.3/ISE_DS/ISE/spartan3/data/spartan3_performance_with_iobpacking.xds" xil_pn:valueState="non-default"/>
     <property xil_pn:name="UserID Code (8 Digit Hexadecimal)" xil_pn:value="0xFFFFFFFF" xil_pn:valueState="default"/>
     <property xil_pn:name="VHDL" xil_pn:value="false" xil_pn:valueState="default"/>
     <property xil_pn:name="VHDL Source Analysis Standard" xil_pn:value="VHDL-93" xil_pn:valueState="default"/>

verilog/sd2snes/srtc.v

@@ -0,0 +1,186 @@
+`timescale 1ns / 1ps
+//////////////////////////////////////////////////////////////////////////////////
+// Company: 
+// Engineer: 
+// 
+// Create Date:    13:33:14 02/09/2011 
+// Design Name: 
+// Module Name:    srtc 
+// Project Name: 
+// Target Devices: 
+// Tool versions: 
+// Description: 
+//
+// Dependencies: 
+//
+// Revision: 
+// Revision 0.01 - File Created
+// Additional Comments: 
+//
+//////////////////////////////////////////////////////////////////////////////////
+module srtc(
+    input clkin,
+	 input [4:0] reg_addr,
+	 input addr_in,
+    input [7:0] data_in,
+    output [7:0] data_out,
+	 input [59:0] rtc_data_in,
+	 output [59:0] rtc_data_out,
+    input reg_we,
+    input reg_oe,
+	 input enable,
+	 output rtc_we,
+	 input reset
+    );
+
+reg rtc_dirty_r;
+assign rtc_dirty = rtc_dirty_r;
+
+reg [59:0] rtc_data_r;
+reg [59:0] rtc_data_out_r;
+assign rtc_data_out = rtc_data_out_r;
+
+reg [3:0] rtc_ptr;
+
+reg [7:0] data_out_r;
+reg [7:0] data_in_r;
+reg [4:0] mode_r;
+reg [3:0] command_r;
+reg rtc_we_r;
+assign rtc_we = rtc_we_r;
+assign data_out = data_out_r;
+
+reg [5:0] reg_oe_sreg;
+always @(posedge clkin) reg_oe_sreg <= {reg_oe_sreg[4:0], reg_oe};
+wire reg_oe_falling = (reg_oe_sreg[5:0] == 6'b100000);
+wire reg_oe_rising = (reg_oe_sreg[5:0] == 6'b000001);
+
+reg [1:0] reg_we_sreg;
+always @(posedge clkin) reg_we_sreg <= {reg_we_sreg[0], reg_we};
+wire reg_we_rising = (reg_we_sreg[1:0] == 2'b01);
+
+reg [1:0] reset_sreg;
+always @(posedge clkin) reset_sreg <= {reset_sreg[0], reset};
+wire reset_rising = (reset_sreg[1:0] == 2'b01);
+
+reg[2:0] we_countdown_r;
+
+parameter SRTC_IDLE = 5'b00001;
+parameter SRTC_READ = 5'b00010;
+parameter SRTC_COMMAND = 5'b00100;
+parameter SRTC_WRITE = 5'b01000;
+parameter SRTC_WRITE2 = 5'b10000;
+
+initial begin
+  rtc_we_r = 0;
+  mode_r <= SRTC_READ;
+  rtc_ptr <= 4'hf;
+end
+
+always @(posedge clkin) begin
+  if(reset_rising) begin
+    mode_r <= SRTC_READ;
+	 rtc_ptr <= 4'hf;
+  end else if(mode_r == SRTC_WRITE2) begin
+    we_countdown_r <= we_countdown_r - 1;
+    if (we_countdown_r == 3'b000) begin
+	   mode_r <= SRTC_WRITE;
+	   rtc_we_r <= 0;
+	 end
+  end else if(reg_we_rising && enable) begin
+    case (addr_in)
+//	   1'b0: // data register is read only
+		  
+		1'b1: // control register
+        case (data_in[3:0])
+          4'hd: begin
+            mode_r <= SRTC_READ;
+            rtc_ptr <= 4'hf;
+          end
+          4'he: begin
+            mode_r <= SRTC_COMMAND;
+          end
+			 4'hf: begin
+			 end
+			 default: begin
+			   if(mode_r == SRTC_COMMAND) begin
+				  case (data_in[3:0])
+				    4'h0: begin
+					   mode_r <= SRTC_WRITE;
+						rtc_data_out_r <= rtc_data_in;
+						rtc_ptr <= 4'h0;
+					 end
+					 4'h4: begin
+					   mode_r <= SRTC_IDLE;                
+						rtc_ptr <= 4'hf;
+					 end
+					 default:
+					   mode_r <= SRTC_IDLE;
+				  endcase
+				end else if(mode_r == SRTC_WRITE) begin
+              rtc_ptr <= rtc_ptr + 1;
+				  case(rtc_ptr)
+				    0: rtc_data_out_r[3:0] <= data_in[3:0];
+				    1: rtc_data_out_r[7:4] <= data_in[3:0];
+				    2: rtc_data_out_r[11:8] <= data_in[3:0];
+				    3: rtc_data_out_r[15:12] <= data_in[3:0];
+				    4: rtc_data_out_r[19:16] <= data_in[3:0];
+				    5: rtc_data_out_r[23:20] <= data_in[3:0];
+				    6: rtc_data_out_r[27:24] <= data_in[3:0];
+				    7: rtc_data_out_r[31:28] <= data_in[3:0];
+				    8: begin
+					   rtc_data_out_r[35:32] <= data_in[3:0] < 10 ? data_in[3:0]
+						                                           : data_in[3:0] - 10;
+						rtc_data_out_r[39:36] <= data_in[3:0] < 10 ? 0 : 1;
+					 end
+				    9: rtc_data_out_r[43:40] <= data_in[3:0];
+				    10: rtc_data_out_r[47:44] <= data_in[3:0];
+				    11: begin
+					   rtc_data_out_r[51:48] <= data_in[3:0] < 10 ? data_in[3:0]
+						                                           : data_in[3:0] - 10;
+						rtc_data_out_r[55:52] <= data_in[3:0] < 10 ? 1 : 2;
+					 end
+				  default:
+				    rtc_dirty_r <= 1;
+				  endcase
+				  mode_r <= SRTC_WRITE2;
+				  we_countdown_r <= 5;
+				  rtc_we_r <= 1;
+				end
+			 end
+        endcase
+	 endcase
+  end else if(reg_oe_falling && enable) begin
+	 case (addr_in)
+ 	   1'b0: // read data register
+		  if(mode_r == SRTC_READ) begin
+		    case(rtc_ptr)
+			   0: data_out_r <= rtc_data_r[3:0];
+				1: data_out_r <= rtc_data_r[7:4];
+				2: data_out_r <= rtc_data_r[11:8];
+				3: data_out_r <= rtc_data_r[15:12];
+				4: data_out_r <= rtc_data_r[19:16];
+				5: data_out_r <= rtc_data_r[23:20];
+				6: data_out_r <= rtc_data_r[27:24];
+				7: data_out_r <= rtc_data_r[31:28];
+				8: data_out_r <= rtc_data_r[35:32] + (rtc_data_r[39:36] << 1) + (rtc_data_r[39:36] << 3);
+				9: data_out_r <= rtc_data_r[43:40];
+				10: data_out_r <= rtc_data_r[47:44];
+				11: data_out_r <= rtc_data_r[51:48] + (rtc_data_r[55:52] << 1) + (rtc_data_r[55:52] << 3) - 10;
+				12: data_out_r <= rtc_data_r[59:56];
+				15: begin
+				  rtc_data_r <= rtc_data_in;
+				  data_out_r <= 8'h0f;
+				end
+				default: data_out_r <= 8'h0f;
+			 endcase
+		    rtc_ptr <= rtc_ptr == 13 ? 15 : rtc_ptr + 1;
+		  end else begin
+		    data_out_r <= 8'h00;
+		  end
+//		  1'b1: // control register is write only
+	 endcase
+  end
+end
+
+endmodule