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flash的指定扇区擦除实验。
先发写指令，再进入写锁存周期等待500ns，进入写扇区擦除指令，然后写扇区地址，页地址，字节地址。即可完成扇区擦除。
模块框图：
时序图：
代码：
module spi (input wire sys_clk ,input wire sys_rst_n , input wire key_start ,output wire miso ,output reg mosi ,output reg cs_n ,output reg sck
);// parameter parameter COMD_W = 8'h06 , // 写指令COMD_B = 8'hc7 , // 全擦除指令COMD_S = 8'hd8 ; // 扇区擦除指令parameter ADR_SE = 8'h00 , // 扇区地址 adress secterADR_PA = 8'h04 , // 页地址 adress pageADR_BY = 8'h25 ; // 字节地址 adress byteparameter IDLE = 4'b0001 ,WREN = 4'b0010 ,WEL = 4'b0100 ,SE = 4'b1000 ;// wire signal deginewire IDLEtoWREN; wire WRENtoWEL ; wire WRENtoSE ; wire SEtoIDLE ; // reg signal definereg [3:0] state_c ;reg [3:0] state_n ;reg [3:0] cnt_20ns ;reg [3:0] cnt_bit ;reg [3:0] cnt_byte ;reg flag_bit ;reg f_b_reg ; // flag_bit_reg的缩写
/****************************************************************************/// 三段式状态机// 现态与次态描述// state_calways @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) state_c <= IDLE ;elsestate_c <= state_n ;end// state_nalways @(*) begincase (state_c)IDLE :if(IDLEtoWREN)state_n <= WREN ;else state_n <= IDLE ;WREN :if(WRENtoWEL)state_n <= WEL ;else state_n <= WREN ;WEL :if(WRENtoSE)state_n <= SE ;else state_n <= WEL ;SE :if(SEtoIDLE)state_n <= IDLE ;else state_n <= SE ;default: state_n <= IDLE ;endcaseend// 状态转移描述assign IDLEtoWREN = ( state_c == IDLE) && ( key_start ) ;assign WRENtoWEL = ( state_c == WREN) && ( f_b_reg ) ;assign WRENtoSE = ( state_c == WEL ) && ( cnt_20ns == 6 ) ;assign SEtoIDLE = ( state_c == SE ) && ( f_b_reg ) ;// 相关信号描述// reg [3:0] cnt_20ns ;always @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) cnt_20ns <= 4'd0 ;else case (state_c)IDLE : cnt_20ns <= 4'd0 ;WREN : if(cnt_20ns || f_b_reg)cnt_20ns <= 4'd0 ;else cnt_20ns <= cnt_20ns + 1'b1 ;WEL : if(cnt_20ns == 6) // 60x20ns==120nscnt_20ns <= 4'd0 ;elsecnt_20ns <= cnt_20ns + 1'b1 ;SE : if(cnt_20ns || f_b_reg)cnt_20ns <= 4'd0 ;else cnt_20ns <= cnt_20ns + 1'b1 ;default: cnt_20ns <= 4'd0 ;endcaseend// reg [3:0] cnt_bit ;always @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n)cnt_bit <= 4'd0 ;else case (state_c)IDLE : cnt_bit <= 4'd0 ;WREN : if(!cnt_20ns && sck && cnt_bit == 7)cnt_bit <= 4'd0 ;else if(!cnt_20ns && sck)cnt_bit <= cnt_bit + 1'b1 ;WEL : cnt_bit <= 4'd0 ;SE : if(!cnt_20ns && sck && cnt_bit == 7)cnt_bit <= 4'd0 ;else if(!cnt_20ns && sck)cnt_bit <= cnt_bit + 1'b1 ;default: cnt_bit <= 4'd0 ;endcaseend// reg [3:0] cnt_bytealways @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) cnt_byte <= 4'd0 ;else if(cnt_bit == 7 && !cnt_20ns && sck && cnt_byte == 4)cnt_byte <= 4'd0 ;else if(cnt_bit == 7 && !cnt_20ns && sck)cnt_byte <= cnt_byte + 1'b1 ;else cnt_byte <= cnt_byte ;end// reg flag_bit ;always @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) flag_bit <= 1'b0 ;elsecase (state_c)IDLE : flag_bit <= 1'b0 ;WREN : if(cnt_bit == 7 && sck && !cnt_20ns)flag_bit <= 1'b1 ;else flag_bit <= flag_bit ;WEL : flag_bit <= 1'b0 ;SE : if(cnt_bit == 7 && sck && !cnt_20ns && cnt_byte == 4)flag_bit <= 1'b1 ;else flag_bit <= flag_bit ;default: flag_bit <= 1'b0 ;endcaseend// reg f_b_reg ;always @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) beginf_b_reg <= 1'b0 ;end else beginf_b_reg <= flag_bit ;endend// output signal// wire miso ,assign miso = 1'bz ;// mosialways @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n)mosi <= 1'b0 ;elsecase (state_c)IDLE : mosi <= 1'b0 ;WREN : if(!cnt_bit) // (cnt_bit == 0)mosi <= COMD_W[7] ;else if(cnt_20ns && sck)mosi <= COMD_W[7 - cnt_bit] ;else mosi <= mosi ;WEL : mosi <= 1'b0 ;SE : case (cnt_byte)1: beginif(!cnt_bit)mosi <= COMD_S[7] ;else if(cnt_20ns && sck)mosi <= COMD_S[7 - cnt_bit] ;else mosi <= mosi ; end2: beginif(!cnt_bit)mosi <= ADR_SE[7] ;else if(cnt_20ns && sck)mosi <= ADR_SE[7 - cnt_bit] ;else mosi <= mosi ; end3: beginif(!cnt_bit)mosi <= ADR_PA[7] ;else if(cnt_20ns && sck)mosi <= ADR_PA[7 - cnt_bit] ;else mosi <= mosi ; end4: beginif(!cnt_bit)mosi <= ADR_BY[7] ;else if(cnt_20ns && sck)mosi <= ADR_BY[7 - cnt_bit] ;else mosi <= mosi ; enddefault: mosi <= 1'b0 ;endcasedefault: mosi <= 1'b0 ;endcaseend// reg cs_n ,always @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) begincs_n <= 1'b1 ;end else begincase (state_c)IDLE : if(key_start)cs_n <= 1'b0 ;else cs_n <= 1'b1 ;WREN : if(f_b_reg)cs_n <= 1'b1 ;else cs_n <= cs_n ;WEL : if(cnt_20ns == 6) cs_n <= 1'b0 ;else cs_n <= cs_n ;SE : if(f_b_reg)cs_n <= 1'b1 ;else cs_n <= cs_n ;default: cs_n <= 1'b1 ;endcaseendend// reg sck always @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n)sck <= 1'b0 ;else case (state_c)IDLE : sck <= 1'b0 ;WREN : if(cnt_20ns)sck <= ~sck ;else sck <= sck ;WEL : sck <= 1'b0 ;SE : if(cnt_20ns)sck <= ~sck ;else sck <= sck ;default: sck <= 1'b0 ;endcaseendendmodule
module top(input wire sys_clk ,input wire sys_rst_n ,input wire key_in ,output wire cs_n ,output wire sck ,output wire mosi
);// 例化间连线wire key_flag ;key_filter key_filter_inst(.sys_clk ( sys_clk ) ,.sys_rst_n ( sys_rst_n ) ,.key_in ( key_in ) ,.key_out ( key_flag )
);spi spi_inst(.sys_clk ( sys_clk ) ,.sys_rst_n ( sys_rst_n ) ,.key_start ( key_flag ) ,.mosi ( mosi ) ,.miso ( ) ,.cs_n ( cs_n ) ,.sck ( sck )
);endmodulemodule key_filter
#(parameter MAX_CNT_20MS = 20'd100_0000
)(input wire sys_clk ,input wire sys_rst_n ,input wire key_in ,output wire key_out
);reg key_r_0 ;reg key_r_1 ;wire nege ;wire pose ;reg [19:00] cnt_20ms ;wire add_cnt_20ms ;wire end_cnt_20ms ;reg add_cnt_flag ;// key_r_0 key_r_1 always @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) beginkey_r_0 <= 1'b1 ;end else beginkey_r_0 <= key_in ;endendalways @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) beginkey_r_1 <= 1'b1 ;end else beginkey_r_1 <= key_r_0 ;endend// nege poseassign nege = ~key_r_0 && key_r_1 ;assign pose = key_r_0 && ~key_r_1 ;// add_cnt_flagalways @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) beginadd_cnt_flag <= 1'b0 ;end else beginif(nege) beginadd_cnt_flag <= 1'b1 ;end else beginif( pose || end_cnt_20ms ) beginadd_cnt_flag <= 1'b0 ;end else beginadd_cnt_flag <= add_cnt_flag ;endend endend// cnt_20ms add_cnt_20ms end_cnt_20msalways @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) begincnt_20ms <= 20'd0 ;end else beginif(add_cnt_20ms) beginif(end_cnt_20ms) begincnt_20ms <= 20'd0 ;end else begincnt_20ms <= cnt_20ms + 20'd1 ;endend else begincnt_20ms <= 20'd0 ;endendendassign add_cnt_20ms = add_cnt_flag ;assign end_cnt_20ms = add_cnt_20ms && cnt_20ms == ( MAX_CNT_20MS - 1'b1 ) ;// key_out// always @(posedge sys_clk or negedge sys_rst_n) begin// // always @(*) begin // 这样的话 会综合成 数据选择器// if(~sys_rst_n) begin// key_out <= 1'b0 ;// end else begin// if(end_cnt_20ms) begin// key_out <= 1'b1 ;// end else begin// key_out <= 1'b0 ;// end// end// endassign key_out = end_cnt_20ms ;
endmodule
仿真图：忘记截屏了。
需要用到仿真模型。
上版验证通过。