rtl: remove RST Time registers

Author: redchenjs

README.md

@@ -8,7 +8,7 @@ WS281X Cube Controller based on MAX10 FPGA.
 * 4-Wire SPI Interface
 * High Refresh Rate (Up to 500fps@8x8x8)
 * 8 Data Lines in Parallel (64 LEDs per line)
-* Configurable Waveform Generator (T0H, T0L, T1H, T1L, RST)
+* Configurable Waveform Generator (T0H, T0L, T1H, T1L)
 * Configurable LED Serial Connection Sequence (Addr Linked List)
 
 ## Commands
@@ -22,21 +22,16 @@ WS281X Cube Controller based on MAX10 FPGA.
 |  2nd Param  |   1 | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |     |
 |  3rd Param  |   1 | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |     |
 |  4th Param  |   1 | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |     |
-|  5th Param  |   1 | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |     |
-|  6th Param  |   1 | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |     |
 
-* 1st Param: T0H Time, unit: 10 ns
-* 2nd Param: T0L Time, unit: 10 ns
-* 3rd Param: T1H Time, unit: 10 ns
-* 4th Param: T1L Time, unit: 10 ns
-* 5th Param: RST Time H, unit: 10 ns
-* 6th Param: RST Time L, unit: 10 ns
+* 1st Param: T0H Time, range: 1-255, unit: 10 ns
+* 2nd Param: T0L Time, range: 1-255, unit: 10 ns
+* 3rd Param: T1H Time, range: 1-255, unit: 10 ns
+* 4th Param: T1L Time, range: 1-255, unit: 10 ns
 
 Limits:
 
-* T0H + T0L <= 255 = 2550 ns = 2.55 us
-* T1H + T1L <= 255 = 2550 ns = 2.55 us
-* RST <= 65535 = 655350 ns = 655.35 us
+* T0H + T0L <= 257 = 2570 ns = 2.57 us
+* T1H + T1L <= 257 = 2570 ns = 2.57 us
 
 ### ADDR_WR
 

rtl/layer_code.sv

@@ -15,11 +15,10 @@ module layer_code(
     input logic [7:0] wr_data_in,
     input logic [3:0] wr_byte_en_in,
 
-    input logic [ 7:0] t0h_cnt_in,
-    input logic [ 7:0] t0l_cnt_in,
-    input logic [ 7:0] t1h_cnt_in,
-    input logic [ 7:0] t1l_cnt_in,
-    input logic [15:0] rst_cnt_in,
+    input logic [7:0] t0h_cnt_in,
+    input logic [7:0] t0l_cnt_in,
+    input logic [7:0] t1h_cnt_in,
+    input logic [7:0] t1l_cnt_in,
 
     output logic ws281x_code_out
 );
@@ -50,7 +49,6 @@ ws281x_ctrl ws281x_ctrl(
 
     .wr_done_in(wr_done_in),
     .rd_data_in(rd_data),
-    .rst_cnt_in(rst_cnt_in),
 
     .bit_rdy_out(bit_rdy),
     .bit_data_out(bit_data),

rtl/layer_conf.sv

@@ -13,24 +13,21 @@ module layer_conf(
     input logic [5:0] wr_addr_in,
     input logic [7:0] wr_data_in,
 
-    output logic [ 7:0] t0h_cnt_out,
-    output logic [ 7:0] t0l_cnt_out,
-    output logic [ 7:0] t1h_cnt_out,
-    output logic [ 7:0] t1l_cnt_out,
-    output logic [15:0] rst_cnt_out
+    output logic [7:0] t0h_cnt_out,
+    output logic [7:0] t0l_cnt_out,
+    output logic [7:0] t1h_cnt_out,
+    output logic [7:0] t1l_cnt_out
 );
 
-logic [ 7:0] t0h_cnt;
-logic [ 7:0] t0l_cnt;
-logic [ 7:0] t1h_cnt;
-logic [ 7:0] t1l_cnt;
-logic [15:0] rst_cnt;
+logic [7:0] t0h_cnt;
+logic [7:0] t0l_cnt;
+logic [7:0] t1h_cnt;
+logic [7:0] t1l_cnt;
 
 assign t0h_cnt_out = t0h_cnt;
 assign t0l_cnt_out = t0l_cnt;
 assign t1h_cnt_out = t1h_cnt;
 assign t1l_cnt_out = t1l_cnt;
-assign rst_cnt_out = rst_cnt;
 
 always_ff @(posedge clk_in or negedge rst_n_in)
 begin
@@ -39,22 +36,17 @@ begin
         t0l_cnt <= 8'h00;
         t1h_cnt <= 8'h00;
         t1l_cnt <= 8'h00;
-        rst_cnt <= 16'h0000;
     end else begin
         if (wr_en_in) begin
-            case (wr_addr_in[2:0])
-                3'h0:
+            case (wr_addr_in[1:0])
+                2'b00:
                     t0h_cnt <= wr_data_in;
-                3'h1:
+                2'b01:
                     t0l_cnt <= wr_data_in;
-                3'h2:
+                2'b10:
                     t1h_cnt <= wr_data_in;
-                3'h3:
+                2'b11:
                     t1l_cnt <= wr_data_in;
-                3'h4:
-                    rst_cnt[15:8] <= wr_data_in;
-                3'h5:
-                    rst_cnt[ 7:0] <= wr_data_in;
             endcase
         end
     end

rtl/layer_ctrl.sv

@@ -32,7 +32,7 @@ logic [2:0] data_en;
 
 logic [5:0] wr_addr;
 
-wire conf_done = (wr_addr == 6'd5);
+wire conf_done = (wr_addr == 6'd3);
 wire code_done = code_wr[0];
 
 wire addr_done = (wr_addr == 6'd63);

rtl/top.sv

@@ -32,11 +32,10 @@ logic       wr_done;
 logic [5:0] wr_addr;
 logic [3:0] wr_byte_en;
 
-logic [ 7:0] t0h_cnt;
-logic [ 7:0] t0l_cnt;
-logic [ 7:0] t1h_cnt;
-logic [ 7:0] t1l_cnt;
-logic [15:0] rst_cnt;
+logic [7:0] t0h_cnt;
+logic [7:0] t0l_cnt;
+logic [7:0] t1h_cnt;
+logic [7:0] t1l_cnt;
 
 sys_ctrl sys_ctrl(
     .clk_in(clk_in),
@@ -84,8 +83,7 @@ layer_conf layer_conf(
     .t0h_cnt_out(t0h_cnt),
     .t0l_cnt_out(t0l_cnt),
     .t1h_cnt_out(t1h_cnt),
-    .t1l_cnt_out(t1l_cnt),
-    .rst_cnt_out(rst_cnt)
+    .t1l_cnt_out(t1l_cnt)
 );
 
 layer_code layer_code7(
@@ -102,7 +100,6 @@ layer_code layer_code7(
     .t0l_cnt_in(t0l_cnt),
     .t1h_cnt_in(t1h_cnt),
     .t1l_cnt_in(t1l_cnt),
-    .rst_cnt_in(rst_cnt),
 
     .ws281x_code_out(ws281x_code_out[7])
 );
@@ -121,7 +118,6 @@ layer_code layer_code6(
     .t0l_cnt_in(t0l_cnt),
     .t1h_cnt_in(t1h_cnt),
     .t1l_cnt_in(t1l_cnt),
-    .rst_cnt_in(rst_cnt),
 
     .ws281x_code_out(ws281x_code_out[6])
 );
@@ -140,7 +136,6 @@ layer_code layer_code5(
     .t0l_cnt_in(t0l_cnt),
     .t1h_cnt_in(t1h_cnt),
     .t1l_cnt_in(t1l_cnt),
-    .rst_cnt_in(rst_cnt),
 
     .ws281x_code_out(ws281x_code_out[5])
 );
@@ -159,7 +154,6 @@ layer_code layer_code4(
     .t0l_cnt_in(t0l_cnt),
     .t1h_cnt_in(t1h_cnt),
     .t1l_cnt_in(t1l_cnt),
-    .rst_cnt_in(rst_cnt),
 
     .ws281x_code_out(ws281x_code_out[4])
 );
@@ -178,7 +172,6 @@ layer_code layer_code3(
     .t0l_cnt_in(t0l_cnt),
     .t1h_cnt_in(t1h_cnt),
     .t1l_cnt_in(t1l_cnt),
-    .rst_cnt_in(rst_cnt),
 
     .ws281x_code_out(ws281x_code_out[3])
 );
@@ -197,7 +190,6 @@ layer_code layer_code2(
     .t0l_cnt_in(t0l_cnt),
     .t1h_cnt_in(t1h_cnt),
     .t1l_cnt_in(t1l_cnt),
-    .rst_cnt_in(rst_cnt),
 
     .ws281x_code_out(ws281x_code_out[2])
 );
@@ -216,7 +208,6 @@ layer_code layer_code1(
     .t0l_cnt_in(t0l_cnt),
     .t1h_cnt_in(t1h_cnt),
     .t1l_cnt_in(t1l_cnt),
-    .rst_cnt_in(rst_cnt),
 
     .ws281x_code_out(ws281x_code_out[1])
 );
@@ -235,7 +226,6 @@ layer_code layer_code0(
     .t0l_cnt_in(t0l_cnt),
     .t1h_cnt_in(t1h_cnt),
     .t1l_cnt_in(t1l_cnt),
-    .rst_cnt_in(rst_cnt),
 
     .ws281x_code_out(ws281x_code_out[0])
 );

rtl/ws281x_code.sv

@@ -31,7 +31,7 @@ logic bit_done, bit_code;
 wire [7:0] t0_sum = t0h_cnt_in + t0l_cnt_in;
 wire [7:0] t1_sum = t1h_cnt_in + t1l_cnt_in;
 
-wire cnt_done = (bit_cnt[8:1] == cnt_sum);
+wire cnt_done = (bit_cnt[8:0] == {cnt_sum, 1'b0} - 2'b11);
 
 wire t0h_time = (bit_cnt[8:1] < t0h_cnt_in);
 wire t1h_time = (bit_cnt[8:1] < t1h_cnt_in);

rtl/ws281x_ctrl.sv

@@ -13,7 +13,6 @@ module ws281x_ctrl(
 
     input logic        wr_done_in,
     input logic [31:0] rd_data_in,
-    input logic [15:0] rst_cnt_in,
 
     output logic bit_rdy_out,
     output logic bit_data_out,
@@ -25,26 +24,25 @@ module ws281x_ctrl(
 parameter [1:0] IDLE     = 2'b00;   // Idle
 parameter [1:0] READ_RAM = 2'b01;   // Read RAM Data
 parameter [1:0] SEND_BIT = 2'b10;   // Send Bit Code
-parameter [1:0] SEND_RST = 2'b11;   // Send RST Code
+parameter [1:0] SYNC_BIT = 2'b11;   // Sync Bit Code
 
 logic [1:0] ctl_sta;
 
 logic       bit_st;
 logic [4:0] bit_sel;
+logic [8:0] bit_syn;
 
 logic bit_rdy, bit_data;
 
 logic        rd_done;
 logic [ 5:0] rd_addr;
 logic [23:0] rd_data;
 
-logic [16:0] rst_cnt;
-
 wire ram_next = (bit_sel == 5'd23);
 wire ram_done = (rd_addr == 6'h00);
 
 wire bit_next = bit_st | bit_done_in;
-wire rst_done = (rst_cnt[16:1] == rst_cnt_in);
+wire syn_done = (bit_syn[8:1] == 8'hfe);
 
 assign bit_rdy_out  = bit_rdy;
 assign bit_data_out = bit_data;
@@ -66,33 +64,30 @@ begin
         rd_done <= 1'b0;
         rd_addr <= 6'h00;
         rd_data <= 24'h00_0000;
-
-        rst_cnt <= 17'h0_0000;
     end else begin
         case (ctl_sta)
             IDLE:
                 ctl_sta <= wr_done_in ? READ_RAM : ctl_sta;
             READ_RAM:
                 ctl_sta <= rd_done ? SEND_BIT : ctl_sta;
             SEND_BIT:
-                ctl_sta <= (bit_next & ram_next) ? (ram_done ? SEND_RST : READ_RAM) : ctl_sta;
-            SEND_RST:
-                ctl_sta <= rst_done ? IDLE : ctl_sta;
+                ctl_sta <= (bit_next & ram_next) ? (ram_done ? SYNC_BIT : READ_RAM) : ctl_sta;
+            SYNC_BIT:
+                ctl_sta <= syn_done ? IDLE : ctl_sta;
             default:
                 ctl_sta <= IDLE;
         endcase
 
         bit_st  <= (ctl_sta != SEND_BIT) & ((ctl_sta == IDLE) | bit_st);
         bit_sel <= (ctl_sta == SEND_BIT) ? bit_sel + bit_next : 5'h00;
+        bit_syn <= (ctl_sta == SYNC_BIT) ? bit_syn + 1'b1 : 9'h000;
 
         bit_rdy  <= (ctl_sta == SEND_BIT) & bit_next;
         bit_data <= (ctl_sta == SEND_BIT) & bit_next ? rd_data[5'd23 - bit_sel] : bit_data;
 
         rd_done <= rd_en_out;
         rd_addr <= rd_done ? rd_data_in[29:24] : rd_addr;
         rd_data <= rd_done ? rd_data_in[23:0] : rd_data;
-
-        rst_cnt <= (ctl_sta == SEND_RST) ? rst_cnt + 1'b1 : 17'h0_0000;
     end
 end