基于FPGA的AD5753（DAC数模转换器）的控制 II（已上板验证）
语言 ：Verilg HDL
EDA工具：Vivado
- 关键词： AD5753 驱动，Verilog HDL,SPI驱动,DAC数模转换器，上板已验证成功
一、引言
本次分享DAC(AD5753) SPI驱动控制器的FPGA实现，可以借鉴到大部分DAC或者ADC的SPI驱动控制，是上篇基于FPGA的AD5753（DAC数模转换器）的控制 I（SPI驱动）文章的续篇。主要包括DAC(AD5753) FPGA的工程实现，仿真以及上板调试，实现了对DAC芯片的寄存器读写控制。
二、基于FPGA的AD5753控制驱动实现
1. 顶层模块
顶层模块代码如下所示，主要包括
（1）AD5753驱动模块：AD5753_driver模块负责与AD5753 DAC通信，发送数据和触发信号。
（2）数据控制模块：AD5753_DATA_Ctrl模块生成要发送给DAC的数据，并控制数据发送。
（3）逻辑分析仪（ILA）：ila实例用于监视和记录信号，以便于调试。
（4）虚拟输入输出（VIO）：vio_0实例用于虚拟探针，可以观察或驱动信号。
clk_wiz_0实例用于生成50MHz的时钟信号clk_50m，并且locked信号表示时钟锁定状态。dac_reset_n输出端口被设置为locked，用于DAC的复位。
module test_ADC5753(
input sys_clk,
input fault_n,
output sdi, // to ac5753
output sclk,
input sdo, // from ad5753
output dac_reset_n,
output sync_n,
output ldac_n,
output led
);
wire [32:0] send_data;
wire send_trig;
wire [32:0] spi_rx_dat;
wire spi_rx_int;
wire send_done ;
//wire spi_clk_i2;
wire spi_clk_i;
wire locked;
wire clk_50m;
wire dat_gen_en;
wire [15:0] data;
clk_wiz_0 clk_wiz_inst
(
.clk_out2(clk_50m),
.clk_out1( ),
.locked (locked ),
.clk_in1 (sys_clk ) //50M
);
assign dac_reset_n = locked;
assign led = 1'b0;
reg[4:0] cnt;
reg clk_1M;
always@(posedge clk_50m or negedge locked)
begin
if(!locked) begin
cnt = 5'b0;
clk_1M = 1'b0;
end
else begin
if(cnt == 5'd24 ) begin
clk_1M = !clk_1M;
cnt = 5'd0;
end
else begin
cnt = cnt +5'b1;
end
end
end
AD5753_driver AD5753_driver (
.clk(clk_50m),
.dac_reset_n(locked),
.fault_n(fault_n),
.send_data(send_data),
.send_trig(send_trig),
.send_done(send_done),
.spi_clk_i(clk_1M),
.spi_rx_dat(spi_rx_dat),
.spi_rx_int(spi_rx_int),
.ldac_n(ldac_n),
.spi_clk(sclk),
.sync_n(sync_n),
.spi_mosi(sdi),
.spi_miso(sdo)
);
AD5753_DATA_Ctrl AD5753_DATA_Ctrl (
.clk(clk_50m),
.spi_clk_i(clk_1M),
.locked(locked),
.data(data),
.send_done(send_done),
.send_trig(send_trig),
.send_data(send_data),
.dat_gen_en(1'b1),
.spi_rx_int(spi_rx_int),
.spi_rx_dat(spi_rx_dat)
);
ila ila_inst (
.clk(clk_50m), // input wire clk
.probe0(send_data), // input wire [23:0] probe0
.probe1(send_trig), // input wire [0:0] probe1
.probe2(spi_rx_dat), // input wire [23:0] probe2
.probe3(spi_rx_int), // input wire [0:0] probe3
.probe4(send_done), // input wire [0:0] probe4
.probe5(locked), // input wire [0:0] probe5
.probe6(dac_reset_n), // input wire [0:0] probe6
.probe7(fault_n), // input wire [0:0] probe7
.probe8(sdi), // input wire [0:0] probe8
.probe9(sclk), // input wire [0:0] probe9
.probe10(sync_n), // input wire [0:0] probe10
.probe11(ldac_n), // input wire [0:0] probe11
.probe12(sdo) // input wire [0:0] probe12
);
vio_0 vio_0 (
.clk(clk_50m), // input wire clk
.probe_in0( ), // input wire [0 : 0] probe_in0
.probe_out0(), // output wire [0 : 0] probe_out0
.probe_out1(data) // output wire [0 : 0] probe_out0
);
endmodule
2. 数据控制模块（AD5753_DATA_Ctrl模块）
AD5753_DATA_Ctrl 模块，设计用于控制与AD5753数字到模拟转换器（DAC）的数据传输。通过定义一系列的输入输出端口、内部状态、计数器和标志位来实现对数据发送过程的精确控制。
模块内部实现了一个状态机，通过不同的状态（如 DATA_IDLE、DATA_FAULT、DATA_Key 等）来管理数据传输流程。状态机根据当前状态和输入信号（例如 dat_gen_en、send_done）来决定下一个状态，并通过 spi_clk_i 来同步数据的发送。
模块还包括了CRC校验逻辑，通过 gen_crc8 子模块生成数据的CRC校验码，确保数据传输的可靠性。在不同的状态下，模块会设置相应的发送触发信号 send_trig 和发送数据 send_data，以及实现特定操作的500us延时，从而完成对AD5753 DAC的命令设置和数据更新。
module AD5753_DATA_Ctrl(
input clk, //50M
input spi_clk_i,
input locked,
input send_done,
output reg send_trig,
output [31:0] send_data,
input dat_gen_en,
input spi_rx_int,
input [15:0] data,
input [31:0] spi_rx_dat
);
// device adress
localparam[2:0] DEVICE_ADRESS=3'b011;
// register
localparam[4:0] NOP=5'h00;
localparam[4:0] Key=5'h00;
// STATE
localparam[4:0] DATA_IDLE = 5'd0;
localparam[4:0] DATA_FAULT = 5'd1;
localparam[4:0] DATA_Key = 5'd2;
localparam[4:0] DATA_Key_wait = 5'd3;
localparam[4:0] DATA_CLEAR = 5'd4;
localparam[4:0] DATA_REQ = 5'd5;
localparam[4:0] DATA_DC_SET = 5'd6;
localparam[4:0] DATA_DC_SET_WAIT = 5'd7;
localparam[4:0] DATA_DC_MOD = 5'd8;
localparam[4:0] DATA_DC_MOD_WAIT = 5'd9;
localparam[4:0] DATA_DAC_SET = 5'd10;
localparam[4:0] DATA_DAC_SET_WAIT = 5'd11;
localparam[4:0] DATA_DAC_MOD = 5'd12;
localparam[4:0] DATA_DAC_MOD_WAIT = 5'd13;
localparam[4:0] DATA_LDAC = 5'd14;
localparam[4:0] DATA_OUTPUT = 5'd15;
localparam[4:0] DATA_REQ_DAC = 5'd16;
localparam[4:0] DATA_REQ_DAC_WAIT = 5'd17;
localparam[4:0] DAC_read = 5'd18;
localparam[4:0] DAC_nop = 5'd19;
reg [13:0] cnt_500us;
reg FLAG;
reg [4:0] state;
reg [4:0] next_state;
reg send_trig_tem;
reg [23:0] send_data_tem;
reg spi_clk_dly;
wire spi_clk_pos;
wire spi_clk_neg;
reg send_done_dly;
wire send_done_pos;
reg FLAG2;
wire[7:0] nextCRC8_D24;
wire crc_out_en;
reg [15:0] data_reg;
reg [15:0] data_reg2;
always @ ( posedge spi_clk_i ) begin
if( ~locked ) begin
data_reg <= 16'b0;
data_reg2 <= 16'b0;
end
else begin
data_reg <= data;
data_reg2 <= data_reg;
end
end
always @ ( posedge spi_clk_i ) begin
if( ~locked )
state <= DATA_IDLE;
else
state <= next_state;
end
always @ (*) begin
if( ~locked )
next_state = DATA_IDLE;
else
case ( state )
DATA_IDLE:
if( dat_gen_en )
next_state = DATA_FAULT;
else
next_state = DATA_IDLE;
DATA_FAULT:
if( send_done )
next_state = DATA_Key;
else
next_state = DATA_FAULT;
DATA_Key:
if( send_done )
next_state = DATA_Key_wait;
else
next_state = DATA_Key;
DATA_Key_wait:
if( FLAG )
next_state = DATA_CLEAR;
else
next_state = DATA_Key_wait;
DATA_CLEAR:
if( send_done )
next_state = DATA_REQ;
else
next_state = DATA_CLEAR;
DATA_REQ:
if( send_done )
next_state = DATA_DC_SET;
else
next_state = DATA_REQ;
DATA_DC_SET:
if( send_done )
next_state = DATA_DC_SET_WAIT;
else
next_state = DATA_DC_SET;
DATA_DC_SET_WAIT:
if( FLAG )
next_state = DATA_DC_MOD;
else
next_state = DATA_DC_SET_WAIT;
DATA_DC_MOD:
if( send_done )
next_state = DATA_DC_MOD_WAIT;
else
next_state = DATA_DC_MOD;
DATA_DC_MOD_WAIT:
if( FLAG )
next_state = DATA_DAC_SET;
else
next_state = DATA_DC_MOD_WAIT;
DATA_DAC_SET:
if( send_done )
next_state = DATA_DAC_SET_WAIT;
else
next_state = DATA_DAC_SET;
DATA_DAC_SET_WAIT:
if( FLAG )
next_state = DATA_LDAC ;
else
next_state = DATA_DAC_SET_WAIT;
// DATA_DAC_MOD:
// if( send_done )
// next_state = DATA_DAC_MOD_WAIT ;
// else
// next_state = DATA_DAC_MOD;
// DATA_DAC_MOD_WAIT:
// if( FLAG )
// next_state = DATA_LDAC ;
// else
// next_state = DATA_DAC_MOD_WAIT;
DATA_LDAC:
if( send_done )
next_state = DATA_OUTPUT ;
else
next_state = DATA_LDAC;
DATA_OUTPUT:
if( send_done )
next_state = DATA_REQ_DAC ;
else
next_state = DATA_OUTPUT;
DATA_REQ_DAC:
if( send_done)
next_state = DATA_REQ_DAC_WAIT ;
else
next_state = DATA_REQ_DAC;
DATA_REQ_DAC_WAIT:
if( FLAG )
next_state = DATA_LDAC ;
else
next_state = DATA_REQ_DAC_WAIT;
DAC_read:
if( send_done )
next_state = DAC_nop;
else
next_state = DAC_read;
DAC_nop:
if( send_done )
next_state = DATA_REQ_DAC;
else
next_state = DAC_nop;
default :
next_state = DATA_IDLE;
endcase
end
always @ ( posedge clk ) begin
if(~locked) begin
spi_clk_dly <= 1'b0;
send_done_dly <= 1'b0;
end
else begin
spi_clk_dly <=spi_clk_i;
send_done_dly <= send_done;
end
end
assign spi_clk_neg = spi_clk_dly && ~spi_clk_i;
assign spi_clk_pos = (~spi_clk_dly )&& spi_clk_i;
assign send_done_pos =( ~send_done_dly) && send_done;
reg[7:0] nextCRC8_D24_tem;
//assign send_trig =crc_out_en;
assign send_data ={send_data_tem,nextCRC8_D24_tem};
always@( posedge clk) begin
if( ~locked ) begin
send_trig <= 1'b0;
nextCRC8_D24_tem <=8'b0;
end
if(crc_out_en) begin
send_trig <= 1'b1;
nextCRC8_D24_tem <= nextCRC8_D24;
end
else if(send_done)
send_trig <= 1'b0;
else
send_trig <=send_trig;
end
always @ ( posedge clk ) begin
if( ~locked ) begin
send_trig_tem <= 1'b0;
send_data_tem <= 24'b0;
end
else begin
if( state == DATA_IDLE && ~send_done ) begin
send_trig_tem <= 1'b0;
send_data_tem <= 24'b0;
end
else if( state == DATA_FAULT && ~send_done ) begin
send_trig_tem <= 1'b1;
send_data_tem <= {DEVICE_ADRESS,5'h10,16'h005c}; //
end
else if( state == DATA_Key && ~send_done) begin
send_trig_tem <= 1'b1;
send_data_tem <= {DEVICE_ADRESS,5'h08,16'hFCBA};
end
else if( state == DATA_CLEAR && ~send_done ) begin
send_trig_tem <= 1'b1;
send_data_tem <= {DEVICE_ADRESS,5'h14,16'h2000}; //
end
else if( state == DATA_REQ && ~send_done ) begin
send_trig_tem <= 1'b1;
send_data_tem <= {DEVICE_ADRESS,5'h09,16'h0644};
end
else if( state == DATA_DC_SET && ~send_done ) begin
send_trig_tem <= 1'b1;
send_data_tem <= {DEVICE_ADRESS,5'h0C,16'h010E};
end
else if( state == DATA_DC_MOD && ~send_done ) begin
send_trig_tem <= 1'b1;
send_data_tem <= {DEVICE_ADRESS,5'h0B,16'h0020};
end
else if( state == DATA_DAC_SET && ~send_done ) begin
send_trig_tem <= 1'b1;
send_data_tem <= {DEVICE_ADRESS,5'h06,16'h01a8};
end
else if( state == DATA_DAC_MOD && ~send_done ) begin
send_trig_tem <= 1'b1;
send_data_tem <= {DEVICE_ADRESS,5'h01,16'h0000};
end
else if( state == DATA_LDAC && ~send_done ) begin
send_trig_tem <= 1'b1;
send_data_tem <= {DEVICE_ADRESS,5'h07,16'h1DAC};
end
else if( state == DATA_OUTPUT && ~send_done ) begin
send_trig_tem <= 1'b1;
send_data_tem <= {DEVICE_ADRESS,5'h06,16'h01E8}; //D6 = 1
end
else if( state == DATA_REQ_DAC && ~send_done ) begin
send_trig_tem <= 1'b1;
send_data_tem <= {DEVICE_ADRESS,5'h01,data_reg2};
end
else if( state == DAC_read && ~send_done ) begin
send_trig_tem <= 1'b1;
send_data_tem <= {DEVICE_ADRESS,5'h13,16'h02}; //读output寄存器
end
else if( state == DAC_nop && ~send_done ) begin
send_trig_tem <= 1'b1;
send_data_tem <= {DEVICE_ADRESS,NOP,16'h00};
end
else begin
send_trig_tem <= 1'b0;
end
end
end
// 延时500us
always@( posedge spi_clk_i or negedge locked)
begin
if( ~locked) begin
cnt_500us <= 14'b0;
FLAG <= 1'b0;
end
else begin
if(state == DATA_Key_wait ) begin
if(cnt_500us == 14'd1010 ) begin
cnt_500us <= 1'b1;
FLAG <= 1'b1;
end
else begin
cnt_500us <= cnt_500us +14'b1;
FLAG <= 1'b0;
end
end
else if(state == DATA_DC_SET_WAIT ) begin
if(cnt_500us == 14'd1010 ) begin
cnt_500us <= 1'b0;
FLAG <= 1'b1;
end
else begin
cnt_500us <= cnt_500us +14'b1;
FLAG <= 1'b0;
end
end
else if(state == DATA_DC_MOD_WAIT ) begin
if(cnt_500us == 14'd1010 ) begin
cnt_500us <= 1'b0;
FLAG <= 1'b1;
end
else begin
cnt_500us <= cnt_500us +14'b1;
FLAG <= 1'b0;
end
end
else if(state == DATA_REQ_DAC_WAIT ) begin
if(cnt_500us == 14'd16 ) begin
cnt_500us <= 1'b0;
FLAG <= 1'b1;
end
else begin
cnt_500us <= cnt_500us +14'b1;
FLAG <= 1'b0;
end
end
else if(state == DATA_DAC_SET_WAIT ) begin
if(cnt_500us == 14'd1010 ) begin
cnt_500us <= 1'b0;
FLAG <= 1'b1;
end
else begin
cnt_500us <= cnt_500us +14'b1;
FLAG <= 1'b0;
end
end
else if(state == DATA_DAC_MOD_WAIT ) begin
if(cnt_500us == 14'd16 ) begin
cnt_500us <= 1'b0;
FLAG <= 1'b1;
end
else begin
cnt_500us <= cnt_500us +14'b1;
FLAG <= 1'b0;
end
end
else begin
FLAG <= 1'b0;
end
end
end
gen_crc8 gen_crc8 (
.clk(clk),
.rst_n(locked),
.crc_in_en(send_trig_tem),
.Data(send_data_tem),
.nextCRC8_D24(nextCRC8_D24),
.crc_out_en(crc_out_en)
);
endmodule
3、gen_crc8校验模块
gen_crc8 的模块用于生成8位循环冗余校验（CRC）码，模块包含时钟输入 clk，复位信号 rst_n，CRC输入使能 crc_in_en，待处理数据 Data（24位宽），以及CRC校验码输出 nextCRC8_D24 和输出使能 crc_out_en。
模块使用一个寄存器 crc_in_en_d0 来检测 crc_in_en 的边沿，即从0到1的跳变，这通常表示一个新数据块的到来。
在检测到 crc_in_en 的上升沿后，模块根据输入数据 Data 和当前的CRC寄存器值 nextCRC8_D24 来计算新的CRC校验码。CRC的计算使用了一系列异或（XOR）操作，这些操作定义了CRC的多项式。
`timescale 1ns / 1ps
module gen_crc8(
input clk,
input rst_n,
input crc_in_en,
input [23:0] Data,
output reg [7:0] nextCRC8_D24,
output reg crc_out_en
);
reg crc_in_en_d0=0;
always @(posedge clk or negedge rst_n)begin
if(!rst_n)
crc_in_en_d0 <= 1'b0;
else
crc_in_en_d0 <= crc_in_en;
end
always @(posedge clk or negedge rst_n)begin
if(!rst_n)
nextCRC8_D24 <= 'd0;
else if(!crc_in_en_d0 && crc_in_en)begin
nextCRC8_D24[0] <= Data[23] ^ Data[21] ^ Data[19] ^ Data[18] ^ Data[16] ^ Data[14] ^ Data[12] ^ Data[8] ^ Data[7] ^ Data[6] ^ Data[0] ^ nextCRC8_D24[0] ^ nextCRC8_D24[2] ^ nextCRC8_D24[3] ^ nextCRC8_D24[5] ^ nextCRC8_D24[7];
nextCRC8_D24[1] <= Data[23] ^ Data[22] ^ Data[21] ^ Data[20] ^ Data[18] ^ Data[17] ^ Data[16] ^ Data[15] ^ Data[14] ^ Data[13] ^ Data[12] ^ Data[9] ^ Data[6] ^ Data[1] ^ Data[0] ^ nextCRC8_D24[0] ^ nextCRC8_D24[1] ^ nextCRC8_D24[2] ^ nextCRC8_D24[4] ^ nextCRC8_D24[5] ^ nextCRC8_D24[6] ^ nextCRC8_D24[7];
nextCRC8_D24[2] <= Data[22] ^ Data[17] ^ Data[15] ^ Data[13] ^ Data[12] ^ Data[10] ^ Data[8] ^ Data[6] ^ Data[2] ^ Data[1] ^ Data[0] ^ nextCRC8_D24[1] ^ nextCRC8_D24[6];
nextCRC8_D24[3] <= Data[23] ^ Data[18] ^ Data[16] ^ Data[14] ^ Data[13] ^ Data[11] ^ Data[9] ^ Data[7] ^ Data[3] ^ Data[2] ^ Data[1] ^ nextCRC8_D24[0] ^ nextCRC8_D24[2] ^ nextCRC8_D24[7];
nextCRC8_D24[4] <= Data[19] ^ Data[17] ^ Data[15] ^ Data[14] ^ Data[12] ^ Data[10] ^ Data[8] ^ Data[4] ^ Data[3] ^ Data[2] ^ nextCRC8_D24[1] ^ nextCRC8_D24[3];
nextCRC8_D24[5] <= Data[20] ^ Data[18] ^ Data[16] ^ Data[15] ^ Data[13] ^ Data[11] ^ Data[9] ^ Data[5] ^ Data[4] ^ Data[3] ^ nextCRC8_D24[0] ^ nextCRC8_D24[2] ^ nextCRC8_D24[4];
nextCRC8_D24[6] <= Data[21] ^ Data[19] ^ Data[17] ^ Data[16] ^ Data[14] ^ Data[12] ^ Data[10] ^ Data[6] ^ Data[5] ^ Data[4] ^ nextCRC8_D24[0] ^ nextCRC8_D24[1] ^ nextCRC8_D24[3] ^ nextCRC8_D24[5];
nextCRC8_D24[7] <= Data[22] ^ Data[20] ^ Data[18] ^ Data[17] ^ Data[15] ^ Data[13] ^ Data[11] ^ Data[7] ^ Data[6] ^ Data[5] ^ nextCRC8_D24[1] ^ nextCRC8_D24[2] ^ nextCRC8_D24[4] ^ nextCRC8_D24[6];
end
end
always @(posedge clk)begin
crc_out_en <= !crc_in_en_d0 && crc_in_en;
end
endmodule
这个模块是数据传输中确保数据完整性的一个重要组件，通过CRC校验可以检测数据在传输过程中是否出现错误。如果CRC校验失败，系统可以采取相应的措施来纠正或重新发送数据。
三、结尾
本文主要描述如何使用FPGA驱动DAC芯片AD5753，已经在开发板上验证成功。使得配置完成之后，可以正常的控制dac的输出。