课程设计实验报告基于spartan3an的贪吃蛇游戏设计

贪吃蛇游戏设计基于Xilinx Spartan-3anFPGA开发板专业：电子科学与技术学号：姓名： 贪吃蛇游戏设计基于Xilinx Spartan-3anFPGA开发板一、实验要求设计一款贪吃蛇游戏。设计平台为xilinx的spartan3an FPGA开发板。通过VGA接口控制液晶显示器，在液晶显示器上实现该游戏。具体要求为，在液晶显示器上有一移动的”蛇”,通过开发板上的拨码开关实现“蛇”上下左右移动。并且要求“蛇”只能在显示器一定范围内运动，若碰到坐标区域的边缘或者“蛇”的身体，则游戏结束。同时会在屏幕有效区域随机出现“苹果”，“蛇”每吃到一次苹果则表示一次成功操作，得分加1，并在数码管上显示得分。本实验刚开始的蛇身长度定位3。为了便于书写程序，我们设定蛇的最大长度为16。二、实验原理 （1）VGA接口 本开发板提供VGA接口。对硬件进行编程，输出标准的VGA信号（红、绿、蓝三色信号和行、帧同步信号），通过15针VGA接口输出至显示器，可驱动显示器显示图像信号。如下图所示： 在实验中只需使用其中的五个引脚，如上图所示。VGA接口信号基本时序图如下图所示：符号含义垂直同步水平同步时间时钟线数时间时钟TS同步脉冲时间16.7ms41680052132us800TDISP显示时间15.36ms38400048025.6us640TPWVsync脉冲宽度64us160023.84us96TFP前沿320us800010640ns16TBP后沿928us23200291.92us48表1 640*480模式下的VGA时序图信号FPGA管教约束VGA_RT13VGA_GV13VGA_BU13H_SYNCW13V_SYNCY13表2 VGA引脚配置（2）拨码开关 本游戏通过开发板下方的四个拨码开关来实现上下左右控制。4拨码开关直接接入FPGA管脚，用户可自行配置。拨码开关拨到“ON”位置时，其状态为“0”，否则状态为“1”；按键连接原理图如下：信号FPGA管脚约束SW1_1J4SW1_2H3SW1_3J3SW1_4J2表3 4码开关FPGA引脚配置（3）LED数码管此开发板提供4个LED数码管，可显示数字，直接与FPGA相连，其控制方法为扫描式，如图所示，此数码管内部接线为共阴方式，即低电平亮。所以若要控制左边第一个七节灯管输出2的字型，可以先输出“0010010”到CADP,然后输出“0111”到A1A4即可。 信号FPGA管教约束LED_BIT1M2LED_BIT2M3LED_BIT3M4LED_BIT4M5LED_CAN1LED_CBN2LED_CCN3LED_CDN4LED_CET1LED_CFT2LED_CGT3LED_DPR4表4 7段数码管FPGA引脚配置三、实验代码1. 由于本实验涉及的模块较多，我们采用小模块化设计的思想。本设计含有六个子模块，分别是： Game_ctrl_unit Snake_eating_apple Snake Key VGA_control Seg_display顶层模块代码如下：module Greedy_Snake (input clk，input reset，input left，input right，input up，input down，output h_sync，output v_sync，output 2:0 color_out，output 7:0 seg_out，output 3:0 sel)；wire left_key_press，right_key_press， up_key_press， down_key_press；wire 1:0 snake；wire 9:0 x_pos；wire 9:0 y_pos；wire 5:0 apple_x；wire 4:0 apple_y；wire 5:0 head_x；wire 5:0 head_y；wire add_cube；wire 1:0 game_status；wire hit_wall；wire hit_body；wire die_flash；wire restart；wire 6:0 cube_num；Game_ctrl_unit game_ctrl_unit1( .clk(clk)，.reset(reset)，.key1_press(left_key_press)，.key2_press(right_key_press)，.key3_press(up_key_press)，.key4_press(down_key_press)，.game_status(game_status)，.hit_wall(hit_wall)，.hit_body(hit_body)，.die_flash(die_flash)，.restart(restart) )； Snake_eating_apple snake_eating_apple1( .clk(clk)，.reset(reset)，.apple_x(apple_x)，.apple_y(apple_y)，.head_x(head_x)，.head_y(head_y)，.add_cube(add_cube) )；Snake snake（.clk(clk),reset(reset)，.left_press(left_key_press)，.right_press(right_key_press)，.up_press(up_key_press)，.down_press(down_key_press)，.snake(snake)，.x_pos(x_pos)，.y_pos(y_pos)，.head_x(head_x)，.head_y(head_y)，.add_cube(add_cube)，.game_status(game_status)，.cube_num(cube_num)，.hit_body(hit_body)，.hit_wall(hit_wall)，.die_flash(die_flash) )；VGA_control vga_control(.clk(clk)，.reset(reset)，.h_sync(h_sync)， .v_sync(v_sync)， .snake(snake)，.color_out(color_out)，.x_pos(x_pos)， .y_pos(y_pos)，.apple_x(apple_x)，.apple_y(apple_y) )；Key key1( .clk(clk)，.reset(reset),.left(left)，.right(right)，.up(up)，.down(down)，.left_key_press(left_key_press)， .right_key_press(right_key_press)，.up_key_press(up_key_press)，.down_key_press(down_key_press) )； Seg_display Seg_display1( .clk(clk)，.reset(reset)，.add_cube(add_cube)，.seg_out(seg_out)，.sel(sel) )；endmodule2.每个子模块的实现方法及要求 2.1 Game_ctrl_unit本模块从其他模块接受信号，决定游戏状态（ready、play、die），并且产生其他模块的控制信号。在ready的状态下，只要有键按下（上下左右），则蛇就会自动向右运动，从而进入play的状态。在play状态下，本模块等待hit_wall或者hit_body的信号，如果这两个信号发生，则进入die状态，即游戏结束。在die状态下，屏幕会闪烁一段时间，最后进入ready状态。此子模块代码如下：module Game_ctrl_unit(input clk，input reset，input key1_press，input key2_press，input key3_press，input key4_press，input hit_wall，input hit_body，output reg 1:0 game_status，output reg die_flash，output reg restart)；localparam RESTART = 2b00；localparam START = 2b01；localparam PLAY = 2b10；localparam DIE = 2b11；reg 31:0 clk_cnt；always ( posedge clk ) begin if( !reset ) begin game_status = START； clk_cnt = 0； die_flash = 1； restart = 0； endelse begin case( game_status ) RESTART：begin if( clk_cnt = 5 ) begin clk_cnt = clk_cnt + 1； restart = 1； end else begin game_status = START； clk_cnt = 0； restart = 0； endend START： begin if( key1_press | key2_press | key3_press | key4_press ) begingame_status = PLAY； end end PLAY： begin if( hit_wall | hit_body ) game_status = DIE；end DIE： begin if( clk_cnt = 200000000 ) begin clk_cnt = clk_cnt + 1； if( clk_cnt = 25000000 ) die_flash = 0； else if( clk_cnt = 50000000 ) die_flash = 1； else if( clk_cnt = 75000000 )die_flash = 0； else if( clk_cnt = 100000000 )die_flash = 1； else if( clk_cnt = 125000000 )die_flash = 0； else if( clk_cnt = 150000000 )die_flash = 1； end else begin die_flash = 1； clk_cnt = 0； game_status = RESTART； end end endcaseendendendmodule2.2 Snake 这是本次试验最复杂的部分，此模块需要完成四项任务：（1）保持蛇的运动 （2）根据按下的键改变蛇的运动方向 （3）判断蛇是否碰撞墙或者自己的身体 （4）在液晶显示器上显示根据VGA_control模块此子模块代码如下：module Snake (input clk，input reset，input left_press，input right_press，input up_press，input down_press，input 9:0 x_pos，input 9:0 y_pos，input add_cube，input 1:0 game_status，input die_flash，output reg 1:0 snake，output reg 6:0 cube_num，output 5:0 head_x，output 5:0 head_y，output reg hit_body，output reg hit_wall)；localparam UP = 2b00；localparam DOWN = 2b01；localparam LEFT = 2b10；localparam RIGHT = 2b11；localparam NONE = 2b00；localparam HEAD = 2b01；localparam BODY = 2b10；localparam WALL = 2b11；localparam PLAY = 2b10；reg 31:0 cnt；wire 1:0 direct； reg 1:0 direct_r；assign direct=direct_r；reg 1:0 direct_next；reg change_to_left；reg change_to_right；reg change_to_up；reg change_to_down； reg 5:0 cube_x15:0；reg 5:0 cube_y15:0；reg 15:0 is_exist；reg 2:0 color；assign head_x = cube_x0；assign head_y = cube_y0；always ( posedge clk ) /初始化刚开始时我们设定蛇向右运动if( !reset)direct_r=RIGHT ；elsedirect_r=direct_next；always ( posedge clk )beginif(!reset ) begin /设定初始化后刚开始三个蛇块的位置cnt = 0；cube_x0 = 10；cube_y0 = 5；cube_x1 = 9；cube_y1 = 5；cube_x2 = 8；cube_y2 = 5；hit_wall = 0；hit_body = 0； endelse begincnt = cnt + 1；if( cnt = 12500000 ) begincnt = 0;if( game_status = PLAY ) begin /在play过程中判断是否hit_wallif( ( direct = UP & cube_y0 = 1 ) | ( direct = DOWN & cube_y0 = 28 )| ( direct = LEFT & cube_x0 = 1 )| ( direct = RIGHT & cube_x0 = 38 ) )hit_wall = 1;/下边判断是否hit_dodyelse if( ( cube_y0 = cube_y1 & cube_x0 = cube_x1 & is_exist1 = 1 )| ( cube_y0 = cube_y2 & cube_x0 = cube_x2 & is_exist2 = 1 )| ( cube_y0 = cube_y3 & cube_x0 = cube_x3 & is_exist3 = 1 )| ( cube_y0 = cube_y4 & cube_x0 = cube_x4 & is_exist4 = 1 )| ( cube_y0 = cube_y5 & cube_x0 = cube_x5 & is_exist5 = 1 )| ( cube_y0 = cube_y6 & cube_x0 = cube_x6 & is_exist6 = 1 )| ( cube_y0 = cube_y7 & cube_x0 = cube_x7 & is_exist7 = 1 )| ( cube_y0 = cube_y8 & cube_x0 = cube_x8 & is_exist8 = 1 )| ( cube_y0 = cube_y9 & cube_x0 = cube_x9 & is_exist9 = 1 )| ( cube_y0 = cube_y10 & cube_x0 = cube_x10 & is_exist10 = 1 )| ( cube_y0 = cube_y11 & cube_x0 = cube_x11 & is_exist11 = 1 )| ( cube_y0 = cube_y12 & cube_x0 = cube_x12 & is_exist12 = 1 )| ( cube_y0 = cube_y13 & cube_x0 = cube_x13 & is_exist13 = 1 )| ( cube_y0 = cube_y14 & cube_x0 = cube_x14 & is_exist14 = 1 )| ( cube_y0 = cube_y15 & cube_x0 = cube_x15 & is_exist15 = 1 ) ) hit_body=1;else /蛇运动过程中相邻模块之间坐标存在联系，依次代替 begincube_x1 = cube_x0；cube_y1 = cube_y0；cube_x2 = cube_x1；cube_y2 = cube_y1；cube_x3 = cube_x2；cube_y3 = cube_y2；cube_x4 = cube_x3；cube_y4 = cube_y3；cube_x5 = cube_x4；cube_y5 = cube_y4；cube_x6 = cube_x5；cube_y6 = cube_y5；cube_x7 = cube_x6；cube_y7 = cube_y6；cube_x8 = cube_x7；cube_y8 = cube_y7；cube_x9 = cube_x8；cube_y9 = cube_y8；cube_x10 = cube_x9；cube_y10 = cube_y9；cube_x11 = cube_x10；cube_y11 = cube_y10；cube_x12 = cube_x11；cube_y12 = cube_y11；cube_x13 = cube_x12；cube_y13 = cube_y12；cube_x14 = cube_x13；cube_y14 = cube_y13；cube_x15 = cube_x14；cube_y15 = cube_y14；case( direct ) /根据运动方向来决定蛇头的坐标UP：beginif( cube_y0 = 1 )hit_wall = 1；else cube_y0 = cube_y0 1；endDOWN： beginif( cube_y0 = 28 )hit_wall = 1；elsecube_y0 = cube_y0 + 1；endLEFT：beginif( cube_x0 = 1 )hit_wall = 1；else cube_x0 = cube_x0 1；endRIGHT： beginif( cube_x0 = 38 )hit_wall = 1；elsecube_x0 = cube_x0 + 1；endendcaseendendendendendalways ( * ) begindirect_next = direct;case( direct )UP: beginif( change_to_left )direct_next = LEFT；else if( change_to_right )direct_next = RIGHT；else direct_next = UP；endDOWN : beginif( change_to_left )direct_next = LEFT；else if( change_to_right )direct_next = RIGHT；else direct_next = DOWN；endLEFT : beginif( change_to_up )direct_next = UP；else if( change_to_down )direct_next = DOWN；else direct_next = LEFT；endRIGHT : beginif( change_to_up )direct_next = UP；else if( change_to_down )direct_next = DOWN；else direct_next = RIGHT；endendcaseendalways ( posedge clk ) beginif( left_press = 1 ) beginchange_to_left = 1；endelse if( right_press = 1 ) beginchange_to_right = 1；endelse if( up_press = 1 ) beginchange_to_up = 1；endelse if( down_press = 1 ) beginchange_to_down = 1；endelse beginchange_to_left = 0；change_to_right = 0；change_to_up = 0；change_to_down = 0；endendreg addcube_state；always ( posedge clk ) beginif( reset = 0 ) beginis_exist = 16b0000000000000111；cube_num = 3；addcube_state = 0；endelse begincase( addcube_state )0: beginif( add_cube ) begincube_num = cube_num + 1；is_existcube_num = 1；addcube_state = 1；endend1: beginif(!add_cube)addcube_state = 0 & x_pos = 0 & y_pos 480 ) beginif( ( x_pos9:4 = 0 | y_pos9:4 = 0 | x_pos9:4 = 39 | y_pos9:4 = 29 ) )snake = WALL;else if( x_pos9:4 = cube_x0 & y_pos9:4 = cube_y0 & is_exist0 = 1 ) beginsnake = ( die_flash = 1 ) ? HEAD : NONE；endelse if( ( x_pos9:4 = cube_x1 & y_pos9:4 = cube_y1 & is_exist1 = 1 )| ( x_pos9:4 = cube_x2 & y_pos9:4 = cube_y2 & is_exist2 = 1 )| ( x_pos9:4 = cube_x3 & y_pos9:4 = cube_y3 & is_exist3 = 1 )| ( x_pos9:4 = cube_x4 & y_pos9:4 = cube_y4 & is_exist4 = 1 )| ( x_pos9:4 = cube_x5 & y_pos9:4 = cube_y5 & is_exist5 = 1 )| ( x_pos9:4 = cube_x6 & y_pos9:4 = cube_y6 & is_exist6 = 1 )| ( x_pos9:4 = cube_x7 & y_pos9:4 = cube_y7 & is_exist7 = 1 )| ( x_pos9:4 = cube_x8 & y_pos9:4 = cube_y8 & is_exist8 = 1 )| ( x_pos9:4 = cube_x9 & y_pos9:4 = cube_y9 & is_exist9 = 1 )| ( x_pos9:4 = cube_x10 & y_pos9:4 = cube_y10 & is_exist10 = 1 )| ( x_pos9:4 = cube_x11 & y_pos9:4 = cube_y11 & is_exist11 = 1 )| ( x_pos9:4 = cube_x12 & y_pos9:4 = cube_y12 & is_exist12 = 1 )| ( x_pos9:4 = cube_x13 & y_pos9:4 = cube_y13 & is_exist13 = 1 )| ( x_pos9:4 = cube_x14 & y_pos9:4 = cube_y14 & is_exist14 = 1 )| ( x_pos9:4 = cube_x15 & y_pos9:4 = cube_y15 & is_exist15 = 1 )snake = ( die_flash = 1 ) ? BODY : NONE；elsesnake = NONE；endend endmodule2.3Snake_eating_apple此模块需要在液晶显示器有效区域内随机产生一个苹果，而且需要判断蛇是否已吃下苹果。此子模块代码如下：module Snake_eating_apple (input clk，input reset，input 5:0 head_x，input 5:0 head_y，output reg 5:0 apple_x，output reg 4:0 apple_y，output reg add_cube)；reg 31:0 clk_cnt；reg 10:0 random_num；always ( posedge clk )random_num = random_num + 927； always ( posedge clk ) beginif( reset = 0 ) beginclk_cnt = 0；apple_x = 24；apple_y = 10；add_cube = 0；endelse beginclk_cnt = clk_cnt + 1；if( clk_cnt = 250000 ) beginclk_cnt = 0；if( apple_x = head_x & apple_y = head_y ) begin add_cube = 1；apple_x 38 ) ? ( random_num10:5 - 25 ) :( random_num10:5 = 0 ) ? 1:random_num10:5；apple_y 28 ) ? ( random_num4:0 - 3 ) :( random_num4:0 = 0 ) ? 1 : random_num4:0； endelse add_cube = 0；endendendendmodule2.4VGA_control此模块直接控制液晶屏的显示。产生五个信号：红、绿、蓝三色信号和行帧同步信号。此子模块代码如下：module VGA_control (input clk，input reset，input 1:0 snake，input 5:0 apple_x，input 4:0 apple_y，output reg 9:0 x_pos，output reg 9:0 y_pos，output reg h_sync，output reg v_sync，output reg 2:0 color_out)；reg 19:0 clk_cnt；reg 9:0 line_cnt；reg clk_25M；localparam NONE = 2b00；localparam HEAD = 2b01；localparam BODY = 2b10；localparam WALL = 2b11；localparam HEAD_COLOR = 3b010；localparam BODY_COLOR = 3b011；reg 3:0 lox；reg 3:0 loy；always ( posedge clk ) beginclk_25M = clk_25M；end/ generate display signalalways ( posedge clk_25M ) beginif( reset = 0) begin clk_cnt = 0；line_cnt = 0；h_sync = 1；v_sync = 1；endelse beginx_pos = clk_cnt 144；y_pos = line_cnt 33；/产生水平控制信号if( clk_cnt = 0 ) beginh_sync = 0；clk_cnt = clk_cnt + 1；endelse if( clk_cnt = 96 ) beginh_sync = 1；clk_cnt = clk_cnt + 1；endelse if( clk_cnt = 799 ) beginclk_cnt = 0；line_cnt = line_cnt + 1；endelse clk_cnt = clk_cnt + 1；/ 产生垂直控制信号if( line_cnt = 0 ) beginv_sync = 0；endelse if( line_cnt = 2 ) beginv_sync = 1；endelse if( line_cnt = 521 ) beginline_cnt = 0；v_sync = 0 & x_pos = 0 & y_pos 480 ) beginlox = x_pos3:0；loy = y_pos3:0；if( x_pos9:4 = apple_x & y_pos9:4 = apple_y )case( loy, lox )8b0000_0000: color_out = 3b000； Default：color_out = 3b001； endcaseelse if( snake = NONE )color_out = 3b000；else if( snake = WALL )color_out = 3b101；else if( snake = HEAD | snake = BODY ) begincase( lox, loy )8b0000_0000: color_out = 3b000；Default：color_out = ( snake = HEAD ) ? HEAD_COLOR : BODY_COLOR；endcaseendendelse color_out = 3b000；endend endmodule2.5Key 本模块根据拨码开关的高低电平，来产生left、right、up和down的信号，从而控制蛇的运动方向。此子模块代码如下：module Key (input clk，input reset，input left，input right，input up，input down，output reg left_key_press，output reg right_key_press，output reg up_key_press，output reg down_key_press)；reg 31:0 clk_cnt；reg left_key_last；reg right_key_last；reg up_key_last；reg down_key_last；always ( posedge clk ) beginif( !reset ) beginclk_cnt = 0；left_key_press = 0；right_key_press = 0；up_key_press = 0；down_key_press = 0；left_key_last = 0；right_key_last = 0；up_key_last = 0；right_key_last = 0；endelse beginif( clk_cnt = 50000 ) beginclk_cnt = 0；left_key_last = left；right_key_last = right；up_key_last = up；down_key_last = down；if( left_key_last = 0 & left = 1 ) beginleft_key_press = 1；endif( right_key_last = 0 & right = 1 ) beginright_key_press = 1；endif( up_key_last = 0 & up = 1 ) beginup_key_press = 1；endif( down_key_last = 0 & down = 1 ) begindown_key_press = 1；endendelse beginclk_cnt = clk_cnt + 1；left_key_press = 0；right_key_press = 0；up_key_press = 0；down_key_press = 0；endendendendmodule2.6 Seg_display 此模块非常简单，类似之前数字秒表实验的设计。此子模块代码如下：module Seg_display(input clk，input reset，input add_cube，output reg 7:0 seg_out，output reg 3:0 sel)；reg 15:0 point；reg 31:0 clk_cnt；always ( posedge clk ) beginif( !reset ) beginseg_out = 0； clk_cnt = 0；sel = 0；endelse beginif( clk_cnt = 200000 ) beginclk_cnt = clk_cnt + 1；if( clk_cnt = 50000 ) beginsel = 4b1110；case( point3:0 )4b0000：seg_out = 8b00000011；4b0001：seg_out = 8b10011111；4b0010：seg_out = 8b00100101；4b0011：seg_out = 8b00001101；4b0100：seg_out = 8b10011001；4b0101：seg_out = 8b01001001；4b0110：seg_out = 8b01000001；4b0111：seg_out = 8b00011111；4b1000：seg_out = 8b00000001；4b1001：seg_out = 8b00001001；default：；endcase endelse if( clk_cnt = 100000 ) beginsel = 4b1101；case( point7:4 )4b0000：seg_out =