/****************************************Copyright (c)**************************************************
**                               張敏　西北核技術研究所一室　2008
**
**--------------File Info-------------------------------------------------------------------------------
** File name:			lcm240128zk03.v
** Last modified Date:	2008-7-26
** Last Version:		1.0
** Descriptions:		lcm240128zk03控制邏輯
**------------------------------------------------------------------------------------------------------
** Created by:			張敏　西北核技術研究所一室
** Created date:		2008-7-26
** Version:				1.0
** Descriptions:		The original version
**
**------------------------------------------------------------------------------------------------------
** Modified by:			
** Modified date:		
** Version:				
** Descriptions:		
**
**------------------------------------------------------------------------------------------------------
********************************************************************************************************/

module lcm240128zk03_interface(
	//模塊輸入
	clk,
	reset_n,
	lcd_int,
	chipselect,
	read,
	write,
	lcd_busy,
	address,
	writedata,
	
	//模塊輸出
	lcd_rs,
	lcd_rw,
	lcd_en,
	lcd_cs1,
	lcd_cs2,
	lcd_rst,
	irq,		//LCD　中斷信號
	readdata,
	lcd_data	//lcd 數據線
	
	);

//Inputs
input clk;			//Input Clock
input reset_n;		//Reset
input lcd_int;		//lcd 中斷
input chipselect;	//Avalon Chip select signal
input read;			//Avalon read
input write;		//Avalon read signal
input lcd_busy;		//lcd busy
input [1:0] address;//Avalon Address bus 
input [7:0] writedata;//Avalon ritedata
	

//Outputs
output lcd_rs;			//lcd 指令、數據控線
output lcd_rw;			//lcd 讀寫線
output lcd_en;			//lcd 使能線
output lcd_cs1;			//lcd cs1
output lcd_cs2;			//lcd cs2
output lcd_rst;			//lcd rst
output irq;				//lcd 中斷
output reg [7:0] readdata;	//IP的輸出，LCD寄存器的值

//inout
inout reg [7:0]	lcd_data;//lcd 數據線

//中間寄存器聲明
reg lcd_rs_r;			//lcd rs
reg lcd_rw_r;			//lcd rw
reg lcd_en_r;			//lcd en
reg lcd_rst_r;			//lcd rst
reg [10:0] timecount;	//狀態機狀態變量
	
//寄存器輸出
assign irq = lcd_int;	//直接將LCD中斷向上報告
assign lcd_cs1 = 1'h0;	//直接將LCD cs1 置0
assign lcd_cs2 = 1'h1;	//直接將LCD cs2 置1

assign lcd_rs = lcd_rs_r;
assign lcd_rw = lcd_rw_r;
assign lcd_en = lcd_en_r;
assign lcd_rst = lcd_rst_r;

//初始化狀態
initial
begin
	readdata<=8'h0;
	lcd_rs_r<= 1'h1;
	lcd_rw_r<= 1'h1;
	lcd_en_r<= 1'h0;
	lcd_rst_r<= 1'h1;
	lcd_data<=8'h0;
	timecount = 10'h0;
	
end

//合成讀、寫控制
wire	read_act;
assign	read_act  = chipselect & read;
wire	write_act;
assign	write_act  = chipselect & write &!lcd_busy;


parameter tcntwritemax = 10'h37;//寫LCD比較耗時，一般需要用到55個時鐘周期約550ns
//write and read
always @(posedge clk )
begin
	if (write_act && !read_act)//AVALON　寫數據
	begin
		case (address)
			2'h0:		//寫指令
			begin
			/*
  LCD_ChkBusy();	//Call LCD_ChkBusy to Check Busy Bit
  LCD_Command = Cmd_Data;
  P2 = 0x91;
  EN = 1;
  _nop_();
  EN = 0;
  P2 = 0x93;
			*/
				if(timecount==10'h0)//首先配置RS、RW，輸出數據
				begin
					lcd_rs_r<= 1;//指令
					lcd_rw_r<= 0;//寫入
					lcd_data<=writedata;//將指令輸出到LCD的數據線
				end
				else if(timecount==10'h8)//第8個時鐘周期輸出lcd的enable高電平,以100M計地址、數據的建立時間約80ns，符合63ns的最小要求
				begin
					lcd_en_r<= 1;
				end
				else if(timecount==10'h35)//0x35=53輸出lcd的enable低電平,以100M計地址、enable的脈寬約450ns,符合400ns的最小要求
				begin
					lcd_en_r<= 0;
				end
				else if(timecount==10'h37)//0x37=55可以拆消地址和數據了,以100M計地址、數據的保持時間約20ns，符合10ns的最小要求，至此寫數據就已經完成了
				begin
					lcd_rs_r<= 1;//指令
					lcd_rw_r<= 1;//讀入
					lcd_data<=8'h0;//將LCD的數據線置0
				end
				else if(timecount>=10'h0 && timecount<=tcntwritemax)
				begin
				end
				else
				begin
					readdata<=8'h0;
					lcd_rs_r<= 1'h1;
					lcd_rw_r<= 1'h1;
					lcd_en_r<= 1'h0;
					lcd_data<=8'h0;
					timecount = 10'h0;
				end
    			if(timecount<=tcntwritemax&&timecount>=0)  begin  timecount = timecount+1;  end
				else  begin  timecount =0; end
			end
			
			2'h1:		//寫數據
			begin
			/*
   LCD_ChkBusy();							//Call LCD_ChkBusy to Check Busy Bit
   LCD_Data = Data_Data;
   P2 = (0x90);
   EN = 1;
   _nop_();
   EN = 0;
   P2 = (0x93);
			*/
				if(timecount==10'h0)//首先拉低RS、RW，輸出數據
				begin
					lcd_rs_r<= 0;//數據
					lcd_rw_r<= 0;//寫入
					lcd_data<=writedata;//將數據輸出到LCD的數據線
				end
				else if(timecount==10'h8)//第8個時鐘周期輸出lcd的enable高電平,以100M計地址、數據的建立時間約80ns，符合63ns的最小要求
				begin
					lcd_en_r<= 1;
				end
				else if(timecount==10'h35)//0x35=53輸出lcd的enable低電平,以100M計地址、enable的脈寬約450ns,符合400ns的最小要求
				begin
					lcd_en_r<= 0;
				end
				else if(timecount==10'h37)//0x37=55可以拆消地址和數據了,以100M計地址、數據的保持時間約20ns，符合10ns的最小要求，至此寫數據就已經完成了
				begin
					lcd_rs_r<= 1;//指令
					lcd_rw_r<= 1;//讀入
					lcd_data<=8'h0;//將LCD的數據線置0
				end
				else if(timecount>=10'h0 && timecount<=tcntwritemax)
				begin
				end
				else
				begin
					readdata<=8'h0;
					lcd_rs_r<= 1'h1;
					lcd_rw_r<= 1'h1;
					lcd_en_r<= 1'h0;
					lcd_data<=8'h0;
					timecount = 10'h0;
				end
    			if(timecount<=tcntwritemax&&timecount>=0)  begin  timecount = timecount+1;  end
				else  begin  timecount =0; end
			end
			
			2'h2:		//重啟LCK,由于RESET時延要求100ms ，過長，無法由硬件產生這么長的時序，改由上層軟件分兩次控制
			begin
				//使用方法為：RESET_LCM240128(base,0),100ms后再RESET_LCM240128(base,1)
				lcd_rst_r <= writedata[0];
			end
			
			default:	//非法地址，將各路信號置為默認狀態
			begin
				//readdata<=8'h0;
				lcd_rs_r<= 1'h1;
				lcd_rw_r<= 1'h1;
				lcd_en_r<= 1'h0;
				lcd_data<=8'h0;
				timecount = 10'h0;
			end
		endcase
	end if (read_act && !write_act)//AVALON　讀數據，讀數據只用0個等待周期
	begin
		case (address)
			2'h0:		//讀指令
			begin//未用到，返回0
				readdata <= 8'h0;
			end
			
			2'h1:		//讀數據
			begin//未用到，返回0
				readdata <= 8'h0;
			end
			
			2'h2:		//讀取LCD的BUSY情況
			begin
				//使用方法為：CHECK_BUSY_LCM240128(base)
				readdata <= {7'h0,lcd_busy};
			end
			
			default:	//非法地址，將各路信號置為默認狀態
			begin
				readdata<=8'h0;
				lcd_rs_r<= 1'h1;
				lcd_rw_r<= 1'h1;
				lcd_en_r<= 1'h0;
				lcd_data<=8'h0;
				timecount = 10'h0;
			end
		endcase
	end
	else if(lcd_busy)//如果處于忙碌狀態，則跳過此次操作,嚴格來講，應該是busy只影響寫操作
	begin
	
	end
	else//非讀、非寫、非忙時，將各路信號置為默認狀態
	begin
			readdata<=8'h0;
			lcd_rs_r<= 1'h1;
			lcd_rw_r<= 1'h1;
			lcd_en_r<= 1'h0;
			lcd_data<=8'h0;
			timecount = 10'h0;
	end
end



endmodule