--- /dev/null
+read_verilog <<EOT
+module top (
+ input CLK, PIN_1, PIN_2, PIN_3, PIN_4, PIN_5,
+ PIN_6, PIN_7, PIN_8, PIN_9, PIN_10, PIN_11, PIN_12, PIN_13, PIN_25,
+ output USBPU, PIN_14, PIN_15, PIN_16, PIN_17, PIN_18,
+ PIN_19, PIN_20, PIN_21, PIN_22, PIN_23, PIN_24,
+);
+ assign USBPU = 0;
+
+ wire[5:0] parOut;
+ wire[5:0] chrg;
+
+ assign PIN_14 = parOut[0];
+ assign PIN_15 = parOut[1];
+ assign PIN_16 = parOut[2];
+ assign PIN_17 = parOut[3];
+ assign PIN_18 = parOut[4];
+ assign PIN_19 = parOut[5];
+ assign chrg[0] = PIN_3;
+ assign chrg[1] = PIN_4;
+ assign chrg[2] = PIN_5;
+ assign chrg[3] = PIN_6;
+ assign chrg[4] = PIN_7;
+ assign chrg[5] = PIN_8;
+
+ SSCounter6o sc6(PIN_1, CLK, PIN_2, PIN_9, chrg, parOut);
+
+endmodule
+
+module SSCounter6 (input wire rst, clk, adv, jmp, input wire [5:0] in, output reg[5:0] out);
+ always @(posedge clk, posedge rst)
+ if (rst) out <= 0;
+ else if (adv || jmp) out <= jmp ? in : out + 1;
+endmodule
+
+// Optimized 6 bit counter, it should takes 7 cells.
+/* b[5:1] /* b[0]
+1010101010101010 in 1010101010101010 in
+1100110011001100 jmp 1100110011001100 jmp
+1111000011110000 loop 1111000011110000 loop
+1111111100000000 carry 1111111100000000 -
+---------------------- ----------------------
+1000101110111000 out 1000101110001011 out
+ 8 B B 8 8 B 8 B
+*/
+module SSCounter6o (input wire rst, clk, adv, jmp, input wire [5:0] in, output wire[5:0] out);
+ wire[4:0] co;
+ wire[5:0] lo;
+ wire ien;
+ SB_LUT4 #(.LUT_INIT(16'hFFF0)) lien (ien, 0, 0, adv, jmp);
+ SB_CARRY c0 (co[0], jmp, out[0], 1),
+ c1 (co[1], jmp, out[1], co[0]),
+ c2 (co[2], jmp, out[2], co[1]),
+ c3 (co[3], jmp, out[3], co[2]),
+ c4 (co[4], jmp, out[4], co[3]);
+ SB_DFFER d0 (out[0], clk, ien, rst, lo[0]),
+ d1 (out[1], clk, ien, rst, lo[1]),
+ d2 (out[2], clk, ien, rst, lo[2]),
+ d3 (out[3], clk, ien, rst, lo[3]),
+ d4 (out[4], clk, ien, rst, lo[4]),
+ d5 (out[5], clk, ien, rst, lo[5]);
+ SB_LUT4 #(.LUT_INIT(16'h8B8B)) l0 (lo[0], in[0], jmp, out[0], 0);
+ SB_LUT4 #(.LUT_INIT(16'h8BB8)) l1 (lo[1], in[1], jmp, out[1], co[0]);
+ SB_LUT4 #(.LUT_INIT(16'h8BB8)) l2 (lo[2], in[2], jmp, out[2], co[1]);
+ SB_LUT4 #(.LUT_INIT(16'h8BB8)) l3 (lo[3], in[3], jmp, out[3], co[2]);
+ SB_LUT4 #(.LUT_INIT(16'h8BB8)) l4 (lo[4], in[4], jmp, out[4], co[3]);
+ SB_LUT4 #(.LUT_INIT(16'h8BB8)) l5 (lo[5], in[5], jmp, out[5], co[4]);
+endmodule
+EOT
+hierarchy -top top
+flatten
+equiv_opt -multiclock -map +/ice40/cells_sim.v synth_ice40