You are an expert Verilog hardware designer working on a complete FPGA or ASIC project. You are given the full source code of a Verilog project. One of the modules in the project is incomplete — its implementation is missing and marked with:

// >>> Module Implementation Begin

// <<< Module Implementation End

Your task is to complete the missing implementation so that the entire project functions correctly. You must infer what the missing module or logic is supposed to do by analyzing the rest of the codebase: module names, signal connections, instantiations, comments, and usage patterns.

Follow these rules:

1. Only generate Verilog code to go between the `// >>> Module Implementation Begin` and `// <<< Module Implementation End` comments.
2. Use Verilog-2001 syntax. Ensure the code is synthesizable.
3. Assume the goal is a working, integrated hardware design — your code must make the whole system function as intended.
4. Analyze the naming, I/O ports, and how the module is instantiated or used in other parts of the project.
5. Implement correct behavior based on design context. Do not guess randomly — reason it out.
6. Avoid vendor-specific features unless explicitly required.
7. Do not output comments, explanation, or anything outside the required code region unless explicitly asked.

Your output should contain **only the Verilog code** that fits inside the marked region.

/*
 * Copyright (c) 2024 ParallelLogic
 * SPDX-License-Identifier: Apache-2.0
 */

`default_nettype none
//`include "charlie.v"
//`include "spi_slave.v"

module tt_um_wokwi_413386991502909441 (//tt_um_parallellogic_top
    input  wire [7:0] ui_in,    // Dedicated inputs
    output wire [7:0] uo_out,   // Dedicated outputs
    input  wire [7:0] uio_in,   // IOs: Input path
    output wire [7:0] uio_out,  // IOs: Output path
    output wire [7:0] uio_oe,   // IOs: Enable path (active high: 0=input, 1=output)
    input  wire       ena,      // always 1 when the design is powered, so you can ignore it
    input  wire       clk,      // clock
    input  wire       rst_n     // reset_n - low to reset
);

  parameter RW_REG_COUNT=23;
  parameter RO_REG_COUNT=1;
  wire [7:0] rw_data [0:(RW_REG_COUNT-1)];
  wire [7:0] ro_data [0:(RO_REG_COUNT-1)];
  wire [(8*24-1):0] memory_frame_buffer;//flatten to work with yosys expectations of 1D lists
  wire [31:0] counter;
  //wire is_lfsr;
  //wire [3:0] tap_index;
  //wire [3:0] tap_out;
  wire [RW_REG_COUNT*8-1:0] rw_flat;
  wire [RO_REG_COUNT*8-1:0] ro_flat;
  
  //IO
  wire mosi=ui_in[2];//^is_input_inverted[2];
  wire sclk=ui_in[1];//^is_input_inverted[1];
  wire cs=ui_in[0];//^is_input_inverted[0];
  wire trigger=ui_in[3]^is_input_inverted[3];
  wire [3:0] asic_in=ui_in[7:4]^is_input_inverted[7:4];
  wire [6:0] asic_out;
  wire miso;
  wire [7:0] bi_out;
  wire [7:0] bi_en;
  assign uo_out[6:0]=asic_out^{7{is_mux_output_inv}};
  assign uo_out[7]=miso;//^is_miso_inverted;
  assign uio_out=bi_out^{8{is_bi_output_inv}};
  assign uio_oe=bi_en^{8{is_bi_en_inv}};
  
  //register map
  wire is_counter_reset=rw_data[16][7];
  wire is_lfsr=rw_data[16][6];
  wire is_clk_div_bypass=rw_data[16][5];
  wire [4:0] clk_tap_index=rw_data[16][4:0];
  wire [1:0] mega_mux_index=rw_data[22][1:0];
  wire [1:0] bi_frame_index=rw_data[19][1:0];
  wire is_bi_mirror=rw_data[19][2];
  wire [1:0] sig_gen_loop_mode=rw_data[20][1:0];
 wire is_trigger_on_rising_edge=rw_data[20][2];
 wire is_trigger_on_falling_edge=rw_data[20][3];
 wire is_save_rising_timestamp=rw_data[20][4];
 wire is_save_falling_timestamp=rw_data[20][5];
 wire [7:0] is_input_inverted=rw_data[22]; 
 wire is_mux_output_inv=rw_data[22][2];
 wire is_bi_output_inv=rw_data[19][4];
 wire is_bi_en_inv=rw_data[19][3];
 
  wire [3:0] sig_gen_out;
  wire [4:0] spi_address;
  wire [7:0] spi_data;
  wire is_spi_write;
  wire [RW_REG_COUNT-1:0] spi_write_flag=1'b1<<spi_address;
  wire [RW_REG_COUNT*8-1:0] sig_gen_data;//updates to the register map configuration in response to trigger events
  wire [RW_REG_COUNT-1:0] sig_gen_flag;//flag to indicate new data is available
  wire is_sig_gen_run;
  
      genvar i;  // Generate variable for the loop
    generate
        for (i = 0; i < RW_REG_COUNT; i = i + 1) begin : gen_priority_write_blocks// : module_instances
            // Instantiate the module here
            priority_write #(2) this_priority_write (
				.clk(clk),
				.rst_n(rst_n),
                .flags({spi_write_flag[i]&is_spi_write,sig_gen_flag[i]}),//flag from each module requesting a write
                .data_bits({spi_data,sig_gen_data[i*8+:8]}),//byte from the module requesting to be written
                .data_in(rw_data[i]),//old value of the register
                .data_out(rw_data[i])//new value of the register
            );
        end
    endgenerate
  
  //assign memory_frame_buffer={rw_data[7], rw_data[6], rw_data[5], rw_data[4], rw_data[3], rw_data[2], rw_data[1], rw_data[0]};
  //flatten 2d list to 1d
    /*  genvar i;
    generate
        for (i = 0; i < RW_REG_COUNT; i = i + 1) begin
            assign memory_frame_buffer[(i*8) +: 8] = rw_data[i];
        end
        for (i = 0; i < RO_REG_COUNT; i = i + 1) begin
            assign memory_frame_buffer[((i+RW_REG_COUNT)*8) +: 8] = ro_data[i];
        end
    endgenerate*/
	assign memory_frame_buffer={ro_flat,rw_flat};//MSbit to LSbit
  
  
  //genvar i;
	generate
		for (i = 0; i < RW_REG_COUNT; i = i + 1) begin : gen_flatten_rw
			//assign rw_data[i] = rw_flat[8*i + 7 -: 8];
			assign rw_flat[8*i + 7 -: 8] = rw_data[i];
		end
		for (i = 0; i < RO_REG_COUNT; i = i + 1) begin : gen_flatten_ro
			assign ro_flat[8*i + 7 -: 8] = ro_data[i];
		end
	endgenerate
  
  
    /*always @(posedge clk) begin
		if(!rst_n) begin
			ro_data[0][7:0]<=0;//TODO
		end else begin
			ro_data[0][7:0]<=8'hE5;//TODO
		end
	end*/
	assign ro_data[0][7:0]=8'hE5;
  
  lfsr_counter lfsr_counter_0(
    .clk(clk),         // Clock input
    .rst_n(rst_n&!is_counter_reset),       // Active-low reset
    .is_lfsr(is_lfsr),     // Mode control: 1 for LFSR, 0 for counter
	//.tap_index(tap_index),
    .out(counter)//,   // 16-bit output
	//.tap_output(tap_out)
  );
  
  charlie charlie_0(
  .clk(clk),      // clock
  .charlie_index(counter[5:0]),
  .frame_index(bi_frame_index),
  .is_mirror(is_bi_mirror),
    .memory_frame_buffer(memory_frame_buffer),
    .uio_out(bi_out),  // IOs: Output path
    .uio_oe(bi_en)
  );
  
  spi_slave #(
    RW_REG_COUNT,  // Number of read-write registers
    RO_REG_COUNT   // Number of read-only registers
)spi_slave_0  (
    .clk(clk),                  // System clock
    .rst_n(rst_n),                // Active-low reset
    .spi_cs(cs),                   // SPI chip select (active low)
    .spi_clk(sclk),                  // SPI clock
    .spi_mosi(mosi),                 // Master-Out Slave-In (data from master)
    .spi_miso(miso),                // Master-In Slave-Out (data to master)
	.rw_data(rw_flat),
    .ro_data(ro_flat), // Data for read-only registers
	.spi_address(spi_address),				//address of where to write data to
	.spi_data(spi_data),					//data byte ready for writing into memory
	.is_spi_write(is_spi_write)
);


signal_generator #(
    RW_REG_COUNT  // Number of input flags and data sets
) signal_generator_0 (
	.clk(clk),
	.trigger(trigger),
	.clk_div(counter[clk_tap_index]),
	.is_div_bypass(is_clk_div_bypass),//set to 1 to run sig gen at max speed (at speed of sys clock)
	.counter(counter),//for saving the timestamp of trigger events
	.rst_n(rst_n),
	.loop_mode(sig_gen_loop_mode),//0 is off, 1 is single, 2 is multi (once per trigger), 3 is loop
	.is_trigger_on_rising_edge(is_trigger_on_rising_edge),
	.is_trigger_on_falling_edge(is_trigger_on_falling_edge),
	.is_save_rising_timestamp(is_save_rising_timestamp),
	.is_save_falling_timestamp(is_save_falling_timestamp),
	.was_config(rw_flat),
	.is_config(sig_gen_data),//data reqeusted to be written to registers
	.is_update_flag(sig_gen_flag),//flag to indicate data is ready to be written
	.sig_gen_out(sig_gen_out),
	.is_running(is_sig_gen_run)
);

	wire [4*7-1:0] mega_mux={
							rw_data[{1'b0,asic_in}][6:0]&{7{sig_gen_out[0]}},//dimmable display
							is_clk_div_bypass?clk:counter[clk_tap_index],counter[clk_tap_index+8],sig_gen_out[3:0],is_sig_gen_run,//2 siggen
							rw_data[{1'b0,asic_in}][6:0],//1 decode
							asic_in,trigger,mosi,sclk//0 echo
							};
	assign asic_out=mega_mux[(mega_mux_index*7)+:7];//8th bit is reserved for miso
	//wire [2:0] _unused2=is_input_inverted[2:0];
 //wire _is_miso_inverted=rw_data[17][7];
  wire _unused = &{ena,uio_in,is_input_inverted[2:0]};//TODO

endmodule


//write verilog code for a spi slave MODE 0 module.  The lower registers are read-write-able (RW_REG_COUNT) while the higher are read-only (RO_REG_COUNT).   The module input/output includes: input wire clk, input wire spi_clk, output reg [RW_REG_COUNT*8-1:0] rw_data, input wire [(RO_REG_COUNT * 8)-1:0] ro_data.  Use always @(posedge clk).  Buffer the byte being read or written.

module spi_slave #(
    parameter RW_REG_COUNT = 23,                 // Number of read-write registers
    parameter RO_REG_COUNT = 1                  // Number of read-only registers
)(
    input wire clk,                             // System clock
    input wire rst_n,                           // Active-low reset
    input wire spi_cs,                          // Chip Select (active low)
    input wire spi_clk,                         // SPI clock
    input wire spi_mosi,                        // Master Out Slave In
    output reg spi_miso,                        // Master In Slave Out
    input wire [RW_REG_COUNT*8-1:0] rw_data,    // Read-write registers
    input wire [(RO_REG_COUNT * 8)-1:0] ro_data,// Flattened read-only data array
	output wire [4:0] spi_address,				//address of where to write data to
	output wire [7:0] spi_data,					//data byte ready for writing into memory
	output wire is_spi_write					//flag to indicate data is on the output wire to be written
);
	
    reg [2:0] bit_cnt;                         // Bit counter for SPI byte
    reg is_mosi;                               // Read mosi (0) or Write miso(1) mode
	wire spi_clk_rising_edge,spi_clk_falling_edge; //SPI Mode 0 state machine
	reg [4:0] reg_address;//address being read/written to
	reg [7:0] reg_data;//data being written to that address or being read out

	reg spi_clk_prev;//for spi_clk_rising_edge,spi_clk_falling_edg state machine
	assign spi_clk_rising_edge=spi_clk & !spi_clk_prev;//rising edge (WAS 0, IS 1), read
	assign spi_clk_falling_edge=!spi_clk & spi_clk_prev;//falling edge (WAS 1, IS 0), change data (write)

	reg is_data_phase;//if receiving address (0), or interacting with data byte (1)
	
	wire [7:0] next_shift_reg={reg_data[6:0], spi_mosi};//shifting master data into slave\
	
	assign is_spi_write=(!spi_cs)&spi_clk_rising_edge&is_data_phase&is_mosi&(bit_cnt==7);
	assign spi_data=next_shift_reg;
	assign spi_address=reg_address[4:0];//TODO, use $bits(param)
	
    // SPI FSM
    always @(posedge clk) begin
		if (!rst_n) begin
			// Reset all internal signals
			is_data_phase <= 1'b0;
			bit_cnt <= 0;
			spi_miso <= 1'b0;
			is_mosi <= 1'b0;
			spi_clk_prev<=1'b0;
			reg_address<=5'b0;
			reg_data<=8'b0;
			//for (int i = 0; i < RW_REG_COUNT; i = i + 1) begin
			//	rw_data[8*i +: 8] <= 8'h00; // Reset to const on boot
			//end
		end else begin
			spi_clk_prev<=spi_clk;
			if(!spi_cs) begin
				if(spi_clk_rising_edge) begin
					if(!is_data_phase) begin
						if (bit_cnt == 7) begin//done receiving one byte
							is_mosi <= next_shift_reg[7];  // MSB determines read/write
							is_data_phase <= 1'b1;
							if (next_shift_reg[7]) begin  //mosi write mode
								reg_address <= next_shift_reg[4:0];//{1'b0,next_shift_reg[6:0]};//save the address for later so it's clear where to save the data byte to in the register map
							end else begin //miso read mode
								if (next_shift_reg[6:0] < RW_REG_COUNT) begin;
									reg_data <= rw_data[next_shift_reg[6:0]*8+7-:8];
								end else if (next_shift_reg[6:0] < RW_REG_COUNT + RO_REG_COUNT) begin
									reg_data <= ro_data[(next_shift_reg[6:0] - RW_REG_COUNT) * 8 + 7-: 8];
								end else begin
									reg_data <= 8'hFF; // Invalid address for read
								end
							end
						end else begin
							//in the middle of receiving a byte, store the bit
							reg_data <= next_shift_reg;//MSB first
						end
						bit_cnt <= bit_cnt + 1;
					end else begin//have the address in-hand, now do the data byte handling
						if (is_mosi) begin  // MOSI write operation (device reads master-to-slave on clk rising)
							if(bit_cnt==7) begin
								//rw_data[reg_address*8+7-:8] <= next_shift_reg; //moved to priority write module
							end
							reg_data <= next_shift_reg;
							bit_cnt <= bit_cnt + 1;
						end 
					end
				end else if(spi_clk_falling_edge) begin
					if(is_data_phase && !is_mosi) begin//MISO slave send data out to master, change on falling edge
						spi_miso <= reg_data[7];
						reg_data <= next_shift_reg;
					end
				end
			end else begin
				is_data_phase<=1'b0;
				bit_cnt <= 0;
			end
		end
	end
endmodule


//`ifndef CHARLIE_V  // Check if MY_MODULE_V is not defined
//`define CHARLIE_V  // Define MY_MODULE_V to prevent re-inclusion
//seems like simulation double-imports, so just skip second import

parameter FRAME_BUFFER_COUNT= 3;
parameter CHARLIE_ROWS= 8*FRAME_BUFFER_COUNT;

module charlie (
  input  wire       clk,      // clock
  input wire[5:0] charlie_index,
  input wire[1:0] frame_index,
  input wire [CHARLIE_ROWS*8-1:0] memory_frame_buffer,
  input wire is_mirror,//mirror left/right
    //input  wire       rst_n,     // reset_n - low to reset
	//input wire is_enabled,
  output wire [7:0] uio_out,  // IOs: Output path
  output wire [7:0] uio_oe   // IOs: Enable path (active high: 0=input, 1=output)
);
// >>> Module Implementation Begin

// <<< Module Implementation End
endmodule



//`endif

//give me verilog code for a combined 32-bit clock and lfsr.  if is_lfsr is 1, then the 32-bit register behaves like a lfsr.  if 0, then the counter counts up.  on !rst_n, resets to all 1's.

module lfsr_counter (
    input wire clk,           // Clock input
    input wire rst_n,         // Active-low reset
    input wire is_lfsr,       // Mode control: 1 for LFSR, 0 for counter
    //input wire [3:0] tap_index,       // Mode control: 1 for LFSR, 0 for counter
    output reg [31:0] out//,     // 32-bit output
    //output wire [3:0] tap_output     // 32-bit output
);

    // Polynomial: x^32 + x^22 + x^2 + x + 1 (0x80200003)
    wire feedback = out[31] ^ out[21] ^ out[1] ^ out[0];
	//assign tap_output = out[tap_index+3-:4];

    always @(posedge clk) begin
        if (!rst_n) begin
            // Reset to all 1's on active-low reset
            out <= is_lfsr?32'hFFFFFFFF:32'h0;
        end else begin
            if (is_lfsr) begin
                // LFSR mode: shift and apply feedback
                out <= {out[30:0], feedback};
            end else begin
                // Counter mode: increment by 1
                out <= out + 1;
            end
        end
    end

endmodule


//give me verilog code for a priority_write module.  The module will accept a parameterized INPUT_COUNT.  There will be INPUT_COUNT flags, and INPUT_COUNT*8 data_bits.  THe module checks if the first flag is 1, and if so outputs the 8 data bits associated with that flag.  If the first flag is 0, then it checks the next flag and outputs those 8 bits if that flag is 1, and so on.  IF no flag is raised, the prior value of the data register is output.  DO not clk or register

module priority_write #(
    parameter INPUT_COUNT = 4  // Number of input flags and data sets
) (
	input wire clk,
	input wire rst_n,
    input wire [INPUT_COUNT-1:0] flags,             // Array of flags
    input wire [(INPUT_COUNT*8)-1:0] data_bits,     // Concatenated 8-bit data inputs
    input wire [7:0] data_in,                       // Input to hold previous data_out value
    output reg [7:0] data_out                      // 8-bit output (wire type)
);

    // Function to get the highest-priority active data
    /*function [7:0] get_priority_data;
        input [INPUT_COUNT-1:0] flags;
        input [(INPUT_COUNT*8)-1:0] data_bits;
        integer i;
        begin
            get_priority_data = data_in;  // Default to data_in if no flags are active
            for (i = 0; i < INPUT_COUNT; i = i + 1) begin
                if (flags[i]) begin
                    get_priority_data = data_bits[(i*8) +: 8]; // Select data associated with the first active flag
                    disable for;  // Stop checking further flags once an active flag is found
                end
            end
        end
    endfunction*/
	
	integer i;
    always @(posedge clk) begin
		if(!rst_n) begin
			data_out <= 8'b0;
		end else begin
			data_out <= data_in; // Default output if no flag is set
			for (i = 0; i < INPUT_COUNT; i = i + 1) begin
				if (flags[i]) begin
					data_out <= data_bits[(i*8) +: 8]; // Extract and output 8 bits for the first active flag
				end
			end
		end
    end

    // Assign the result of the function to data_out
    //assign data_out = get_priority_data(flags, data_bits);

endmodule


//behavior undefined for signals of length 0 bits

parameter SIG_GEN_RISING_TIMESTAMP_REGISTER=8;//wrere to store timestamp in memory
parameter SIG_GEN_FALLING_TIMESTAMP_REGISTER=12;
parameter SIG_GEN_LENGTH_REGISTER=17;
parameter SIG_GEN_SLEEP_REGISTER=18;
parameter SIG_GEN_CONFIG_REGISTER=20;
parameter SIG_GEN_TRIGGER_COUNT_REGISTER=21;

module signal_generator #(
    parameter RW_REG_COUNT = 22  // Number of input flags and data sets
) (
	input wire clk,
	input wire trigger,//1/0 coming from the input trigger pin
	input wire clk_div,
	input wire is_div_bypass,//set to 1 to run sig gen at max speed (at speed of sys clock)
	input wire [31:0] counter,//for saving the timestamp of trigger events
	input wire rst_n,
	input wire [1:0] loop_mode,//0 is off, 1 is single, 2 is multi (once per trigger), 3 is loop
	input wire is_trigger_on_rising_edge,
	input wire is_trigger_on_falling_edge,
	input wire is_save_rising_timestamp,
	input wire is_save_falling_timestamp,
	input wire [RW_REG_COUNT*8-1:0] was_config,
	output wire [RW_REG_COUNT*8-1:0] is_config,
	output wire [RW_REG_COUNT-1:0] is_update_flag,
	output reg [3:0] sig_gen_out,
	output wire is_running
);

reg prev_clk_div;
reg prev_trigger;
wire is_clk_div_rising_edge=(clk_div&!prev_clk_div)|is_div_bypass;
wire is_trigger_rising_edge=  ( trigger &!prev_trigger)&is_trigger_on_rising_edge  & !is_running;
wire is_trigger_falling_edge=((!trigger)& prev_trigger)&is_trigger_on_falling_edge & !is_running;
wire is_trigger_on_any_edge=is_trigger_on_rising_edge&is_trigger_on_falling_edge;
//wire is_enabled=|loop_mode;
wire is_loop=loop_mode==2'b11;

reg [7:0] index_reg;//in signal mode, this is the index of the bit being output.  in sleep mode, this is the amount of time remaining until the end of the waveform
reg [1:0] state_machine;//0 is awaiting trigger, 1 is bit mode, 2 is sleep
assign is_running=state_machine!=2'b00;
wire [7:0] next_index=index_reg-1;

wire [7:0] all_single_triggers_cleared=was_config[8*SIG_GEN_CONFIG_REGISTER +: 8]&8'b11110010;//clear the rising/falling edge triggers and single-event
wire [7:0] rising_trigger_cleared=was_config[8*SIG_GEN_CONFIG_REGISTER +: 8]&8'b11111011;//clear only the rising trigger flag
wire [7:0] falling_trigger_cleared=was_config[8*SIG_GEN_CONFIG_REGISTER +: 8]&8'b11110111;//clear only the falling trigger flag
wire [7:0] trigger_register_cleared;
wire is_triggered=(is_trigger_rising_edge|is_trigger_falling_edge);
wire [7:0] get_pattern_length={1'b0,was_config[SIG_GEN_LENGTH_REGISTER*8+:7]};//max 128 bits
wire [7:0] get_pattern_length_decrement=get_pattern_length-1;
wire [7:0] get_pattern_sleep_decrement=was_config[SIG_GEN_SLEEP_REGISTER*8+:8]-1;

assign trigger_register_cleared=(loop_mode==2'b1)?(is_trigger_on_any_edge?
									(is_trigger_rising_edge?rising_trigger_cleared:falling_trigger_cleared)://clear only one flag if single capture and listening for both trigger edges
								all_single_triggers_cleared)://clear rising/falling/single triggers if in single-trigger mode
							was_config[8*SIG_GEN_CONFIG_REGISTER +: 8];//no change if in multi/loop trigger modes

  genvar iter;
	generate//create data and flags for priority write structure
		for (iter = 0; iter < RW_REG_COUNT; iter = iter + 1) begin
			if(iter>=SIG_GEN_RISING_TIMESTAMP_REGISTER & iter<(SIG_GEN_RISING_TIMESTAMP_REGISTER+4)) begin : gen_rising_timestamp//store rising edge timestamp
				assign is_config[8*iter +: 8] = counter[(iter-SIG_GEN_RISING_TIMESTAMP_REGISTER)*8+:8];
				assign is_update_flag[iter]=is_trigger_rising_edge&is_save_rising_timestamp;
			end else if(iter>=SIG_GEN_FALLING_TIMESTAMP_REGISTER & iter<(SIG_GEN_FALLING_TIMESTAMP_REGISTER+4)) begin : gen_falling_timestamp//store falling edge timestamp
				assign is_config[8*iter +: 8] = counter[(iter-SIG_GEN_FALLING_TIMESTAMP_REGISTER)*8+:8];
				assign is_update_flag[iter]=is_trigger_falling_edge&is_save_falling_timestamp;
			end else if(iter==SIG_GEN_CONFIG_REGISTER) begin : gen_clear_single//clear the single_snapshot (and associated rising/falling edge) flags
				assign is_config[8*iter +: 8] = trigger_register_cleared;
				assign is_update_flag[iter]=is_triggered;//clear the single snapshot when machine was idle and a trigger_edge happens
			end else if(iter==SIG_GEN_TRIGGER_COUNT_REGISTER) begin : gen_count_triggers
				assign is_config[8*iter +: 8] = was_config[8*iter +: 8]+1;
				assign is_update_flag[iter]=is_triggered;
			end else begin : gen_leave_other_registers_unchanged
				assign is_config[8*iter +: 8] = was_config[8*iter +: 8];
				assign is_update_flag[iter]=1'b0;//never update the other registers
			end
		end
	endgenerate

    always @(posedge clk) begin
		if(!rst_n) begin
			prev_clk_div<=1'b0;
			prev_trigger<=1'b0;
			state_machine<=2'b0;
			sig_gen_out<=4'b0;
			index_reg<=8'b0;
		end else begin
			prev_clk_div <= clk_div;
			prev_trigger <= trigger;
			if(is_triggered) begin
				state_machine<=1;//go to bit mode (PRECON: LEN>0 of bits to write out)
				index_reg<=get_pattern_length_decrement;//first bit written out is at the highest index
				sig_gen_out[0] <= was_config[get_pattern_length];
				//if(is_save_timestamp) begin
					//save clock to bytes 8-11 (rising), DONE in combinational logic
					//save clock to bytes 12-15 (falling), DONE in combinational logic
				//end
			end
			if(is_clk_div_rising_edge & is_running) begin
				index_reg<=next_index;
				if(state_machine==1) begin//if in bit mode, output the bit
					sig_gen_out[0] <= was_config[index_reg];
				end
				if(index_reg==0) begin
					if(state_machine==1) begin
						state_machine<=2;
						index_reg<=get_pattern_sleep_decrement;
					end else if(state_machine==2) begin
						state_machine<=0;//turn OFF unless otherwise directed to continue
						//if(is_single) begin
							//clear the single_shot bit, DONE in combinational logic
						//end
						//if(is_multi) begin
							//default behavior is to return to idle waiting for trigger
						//end
						if(is_loop) begin
							state_machine<=1;//immediately continue generating pattern
							index_reg<=get_pattern_length_decrement;
							sig_gen_out[0] <= was_config[get_pattern_length];
						end
					end
				end
			end
		end
	end
	
endmodule

Reference solution:
rtl/generated.v:   
//reg[5:0] charlie_index;
wire [2:0] row_index;
  wire [2:0] col_index;
  //wire is_diagonal;
  wire is_on;
  wire [7:0] memory [0:CHARLIE_ROWS-1];
  reg [7:0] uio_out_reg;
  reg [7:0] uio_oe_reg;
  
  assign uio_out=uio_out_reg;
  assign uio_oe=uio_oe_reg;
  
  genvar i;
	generate
		for (i = 0; i < CHARLIE_ROWS; i = i + 1) begin
			assign memory[i][7:0] = memory_frame_buffer[8*i + 7 -: 8];
		end
	endgenerate
  
  assign col_index=charlie_index[2:0];
  assign row_index=charlie_index[5:3];
  
  //assign is_diagonal = row_index == col_index;//if on diagonal, do nothing
  assign is_on=memory[row_index+8*frame_index][col_index^{is_mirror,is_mirror,is_mirror}]&(frame_index!=2'b11);//fetch state of this LED
  
  always @(posedge clk)
  begin
    //if(!rst_n) begin
	//	charlie_index <= 6'b0;
	//end else begin
	//	charlie_index <= charlie_index+1;
	//end
    uio_oe_reg<=8'b0;
    uio_out_reg<=8'b0;
    //if(!is_diagonal && is_on) begin
      uio_oe_reg[row_index]<=is_on;
      uio_oe_reg[col_index]<=is_on;
      
      uio_out_reg[row_index]<=1'b1;
      uio_out_reg[col_index]<=1'b0;
   // end
  end