可以先編寫不可綜合的仿真用Verilog,然後再寫可綜合的,如果技術卓越,可以跳過這步:
卷積的長度是不確定的,比如MATALAB裏面的CONV函數,輸入多長的都行,但是需要提前輸入一整個向量(數組),那麼長度也就是定下了:我寫的MATLAB卷積函數也是有測長度的:https://blog.csdn.net/Mr_liu_666/article/details/103372145
但是實際用FPGA的時候,實時卷積,卷積對象是流式輸入的,所以首先定下來一個長度,比如128,那麼我們的Verilog就算128卷積128即可,一次填充128,計算一次,輸出一次。我寫的Verilog用了parameter定義了常量,卷積長度可以隨時改變,爲了雙重for嵌套累加,需要一些臨時reg變量計數,我使用的是8位的,所以最大隻能加到255,卷積長度不能超過128,否則卷積結果長度爲128+128-1=255,變量就不能清零了。
以8位卷積爲例:
卷積結果是1到8到1,modelsim仿真結果如下:
成功得到1到8到1的結果。
卷積模塊代碼:
//模塊:可變長卷積模塊
//功能:算兩個預設長度的寄存器的卷積結果,寄存器的輸入實時更新,卷積結果放在寄存器中,實時輸出
//使用方法:輸入時鐘,低電平復位清空不定態寄存器,load拉高輸入即將計算的數值,
//out拉高輸出結果寄存器的數值
module CONV(
input wire reset,//復位,清空所有寄存器
input wire clk,//時鐘
input wire [7:0] CONV_iData0,//輸入數據
input wire [7:0] CONV_iData1,//輸入數據
output reg [15:0] CONV_oData//輸出數據
);
parameter LengthOfConv = 8;//卷積長度
parameter InState = 4'b0001,ConvState = 4'b0010,OutState = 4'b0100,ClrState = 4'b1000;
//三個mem類型的寄存器
reg [7:0] CONV_iData0reg[LengthOfConv - 1:0];
reg [7:0] CONV_iData1reg[LengthOfConv - 1:0];
reg [15:0] CONV_oDatareg[2*LengthOfConv - 2:0];
reg [7:0]index0;
reg [7:0]index1;//這兩個是初始化,清零用的
reg [7:0]index_input;//輸入計數
reg [7:0]index_conv;
reg [7:0]index_conv2;//卷積計數
reg [7:0]index_output;//輸出計數
reg [7:0]index_clr;//輸出計數
reg [3:0] state,nextstate;
initial
begin
index0 <= 0;
index1 <= 0;
index_input <= 8'b0;
index_conv <= 8'b0;
index_conv2 <= 8'b0;
index_output<= 8'b0;
index_clr <= 8'b0;
state <= InState;
nextstate <= ConvState;
end
always @(posedge clk)//用若干個時鐘週期把卷積輸入寄存器和結果寄存器清零
begin
if(reset == 0)
begin
CONV_iData0reg[index0] <= 8'b0;
CONV_iData1reg[index0] <= 8'b0;
CONV_oDatareg[index1] <= 16'b0;
if(index0 == LengthOfConv - 1)
index0 = 8'b0;
else
index0 <= index0 + 8'b1;
if(index1 == LengthOfConv * 2 - 2)
index1 = 8'b0;
else
index1 <= index1 + 8'b1;
end
else
begin
if(state == InState)//輸入數據
begin
begin
CONV_iData0reg[index_input] <= CONV_iData0;
CONV_iData1reg[index_input] <= CONV_iData1;
index_input <= index_input + 8'b1;
CONV_oData <= 0;//轉換沒有結束的時候,輸出爲0
end
if(index_input >= LengthOfConv - 1)
begin
index_input <= 8'b0;
state <= nextstate;
nextstate <= OutState;
end
end
if(state == ConvState)//計算卷積
begin
CONV_oData <= 0;//轉換沒有結束的時候,輸出爲0
if(index_conv2 <= LengthOfConv-1 &&index_conv <= LengthOfConv-1 )
CONV_oDatareg[index_conv2 + index_conv] = CONV_oDatareg[index_conv2 + index_conv] + CONV_iData0reg[index_conv2]*CONV_iData1reg[index_conv];
if(index_conv2 == LengthOfConv ) //用於代替for循環嵌套,內層
begin
index_conv2 <= 8'b0;
index_conv <= index_conv + 8'b1;
end
else
index_conv2 <= index_conv2 + 8'b1;
if(index_conv == LengthOfConv )
begin
index_conv <= 8'b0;
index_conv2 <= 8'b0;
//clearflag <= ~clearflag;
state <= nextstate;
nextstate <= ClrState;
end
end
if(state == OutState)//輸出狀態
begin
CONV_oData <= CONV_oDatareg[index_output];
index_output <= index_output + 8'b1;
if(index_output == LengthOfConv * 2 - 2)//多一個週期,使輸出完整,但是會多出來一個越界的現象,也就是一個0(因爲我們清零過了)
begin
index_output <= 8'b0; //由於非阻塞賦值的特點,這裏需要從0到LengthOfConv * 2
state <= nextstate;
nextstate <= InState;
end
end
if(state == ClrState)//清除狀態
begin
CONV_oData <= 0;//轉換沒有結束的時候,輸出爲0
CONV_oDatareg[index_clr] = 0;
index_clr<= index_clr + 8'b1;
if(index_clr == LengthOfConv * 2 - 1 )
begin
index_clr <= 8'b0;
state <= nextstate;
nextstate <= ConvState;
end
end
end
end
endmodule
另外,initial裏面的東西仿真的時候管用,綜合以後可能會沒效果:https://blog.csdn.net/Mr_liu_666/article/details/103375653
測試代碼:(這裏使用了可綜合的狀態機,效果不錯)
`timescale 1ns/1ns
module CONV_top();
parameter period = 1;
parameter Rst0State = 2'b00;//前提是state的初值是0
parameter Rst1State = 2'b01;
parameter WorkState = 2'b10;
reg reset;
reg clk;
reg [7:0] CONV_iData0;
reg [7:0] CONV_iData1;
reg [15:0] index_reset;
reg [1:0] State;
always @(posedge clk)
begin
if(State == Rst0State)//開始復位
begin
reset <= 0;
index_reset <= 0;
State <= Rst1State;
end
else
if(State == Rst1State)//保持復位,復位結束
begin
if(index_reset <= 16'hfe)
begin
index_reset <= index_reset + 1;
end
else
begin
//index_reset <= 0;
State <= WorkState;
reset <= 1;
end
end
else
if(State == WorkState)//輸入數據
begin
reset <= 1;
State <= WorkState;
CONV_iData0 = 8'h01;
CONV_iData1 = 8'h01;
end
end
always
begin
# period clk = !clk;
end
CONV CONV0(
.reset(reset),
.clk(clk),
.CONV_iData0(CONV_iData0),
.CONV_iData1(CONV_iData1),
.CONV_oData(CONV_oData)
);
endmodule
接下來應該將其綜合進工程,做一個可視的FPGA實驗,準備做一個累加實驗,使一個跳動的色塊的顏色隨着卷積結果的變化而變化:https://blog.csdn.net/Mr_liu_666/article/details/103376238
關於其MATLAB仿真,見前一篇:https://blog.csdn.net/Mr_liu_666/article/details/103372145