spi控制器程序

《spi控制器程序》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、/*设计一个SPI控制器，接收到发送数据命令以后，主设备首先生成片选信号，然后生成SPI时钟信号。在SPI时钟的上升沿将发送数据（从高位到低位｝送到SPI总线，发送数据完毕后，片选信号置为无效（置高），并撤除SPI时钟。7modulespimaster（rst_n,elk,rd_n,wr_n,datain,spics_n,spiclk,spido,spidi,dataout,dstate）;inputrst_n;//复位信号,低有效inputelk;//时钟信号inputrd_n;//接收数据命令i叩utwr_n;//发送数据命令i

2、叩utspidi;//SPI数据输入信号input[7:0]datain;//发送数据输入outputspics_n;//SPI片选信号,低有效outputspiclk;//SPI时钟信号outputspido;//SPI数据输出信号output[7:0]dataout;//接收数据输出output[7:0]dstate;regspies』;regspiclk;regspido;reg[7:0]ent;//用于计数reg[7:0]dstate;//状态机reg[7:0]dsend;//即datatosend,要发的数据reg[7:0

3、]dreceive;//datatoreceive,要接收的数掘暂时存放在dreceivereg[7:0]dataout;reg[1:0]spistate;//SPI控制器的状态：空闲、发送、接收parameteridle=2'bOO;parametersend_data=2'b01;parameterreceive_data=2'bl0;always@(posedgeelk)beginif(!rst_n)begin//复位，将SPI置为空闲状态spistate<=idle;ent<=8'dO;spics_n<=l'bl;spicl

4、k<=l'bl;spido<=l'bl;dstate<=8'dO;endelsebegin//如果rst_n是高电位，下面分别表述SPImaster的三种状态case(spistate)2'b00:begin//空闲状态，spics_n、spiclk、spido均是高电位spics_n<=l'bl;spiclk<=l'bl;spido<=l'bl;if(cnt==8*d40)begin/////////////???????????????????cnt<=8'dO;if((wr_n==1'bO)&&(rd_n==l'bl))beg

5、in//发送命令有效spistate<=send_data;dstate<=8'dO;dsend<=datain;endelseif((wr_n==l'bl)&&(rd_n==1'bO))begin//接收命令有效spistate<=receive_data;dstate<=8'dO;endendelsebegincnt<=cnt+8*dl;endend2'blO:begin//SPI主端接收数据case(dstate)8'dO:beginspies一n<=1'bO;"spies一n置低，有效spiclk<=l'bl;spido<=

6、l'bl;dstate<=8’dl;//下个elk的上升沿到来吋，检测到的将是dstate=l.end8'dl:beginspics_n<=1'bO;spiclk<=l'bl;spido<=l'bl;dstate<=8'd2;end8'd2:beginspics_n<=1'bO;spiclk<=1'bO;spido<=l'bl;dstate<=8'd3;end8'd3:beginspics_n<=1'bO;spiclk<=l'bl;dstate<=8'd4;end8'd4:beginspics_n<=1'bO;spiclk<=1’b

7、O;//spiclk的下降沿dreceive[7]<=spidi;//接收第7位dstate<=8'd5;end8'd5:beginspies一n<=1'bO;spiclk<=l’bl;//spiclk的上升沿dstate<=8'd6;end8'd6:beginspies一n<=1'bO;spiclk<=1'bO;dreceive[6]<=spidi;//接收第6位dstate<=8'd7;end8'd7:beginspics_n<=1'bO;spiclk<=l'bl;dstate<=8'd8;end8'd8:beginspics_

8、n<=1'bO;spiclk<=1'bO;dreceive[5]<=spidi;//接收第5位dstate<=8'd9;end8'd9:beginspics_n<=1'bO;spiclk<=l'bl;dstate<=8'dlO;end