如何實(shí)現(xiàn)一種基于ZYNQ的簡單FSK基帶發(fā)射器？

緒論

由于某種需求需要生成正弦波，因此使用 C 應(yīng)用程序中的sin()函數(shù)來計(jì)算單位圓的幅度值，然后將該幅度值轉(zhuǎn)換為 AD9717 的適當(dāng) DAC 代碼（當(dāng)然將每個(gè)角度值轉(zhuǎn)換為弧度）。

能夠使用DAC生成簡單的正弦波，下一個(gè)想法就是在 SDR（軟件定義無線電）中使用頻率調(diào)制。

大多數(shù) SDR 設(shè)計(jì)都有 3 個(gè)不同的內(nèi)部運(yùn)行頻率：一個(gè)低基帶頻率，用于處理來自 ADC/DAC 的數(shù)據(jù)；一個(gè)或多個(gè)中間頻率，最終基帶數(shù)據(jù)流作為中間步驟提升到該頻率；以及最終的 RF 將輸入/輸出天線的輸出頻率。顯然，最簡單的起點(diǎn)是基帶，因?yàn)樗亲畹皖l率，并且是實(shí)際模擬數(shù)據(jù)流從各個(gè)數(shù)字?jǐn)?shù)據(jù)位組合在一起/提取的地方。為了進(jìn)一步縮小范圍，1 和 0 的數(shù)字位與某些相關(guān)模擬波形相關(guān)的確切點(diǎn)被稱為符號(hào)映射器，它是前面提到的 SDR 基本構(gòu)建塊。

因此，本項(xiàng)目將是一個(gè)非常簡化的基帶符號(hào)映射器，用于 FSK 數(shù)字調(diào)制方案的鏈（數(shù)字到模擬）的發(fā)送端。

數(shù)字調(diào)制

頻移鍵控 (FSK) 是一種數(shù)字調(diào)制，通過更改頻率來表示數(shù)據(jù)流中的不同位/符號(hào)。在其最基本的形式中，一個(gè)頻率用于表示二進(jìn)制 1，另一個(gè)頻率用于表示二進(jìn)制 0。這種形式的 FSK 被稱為二進(jìn)制 FSK 或 2-FSK。

從上面可以看出，1比特由大約是表示0比特的頻率的兩倍的頻率來表示。對(duì)于 ZYNQ+SDR 來說，這意味著它需要能夠分別以連續(xù)相位輸出兩個(gè)不同的頻率。換句話說：定時(shí)在這里很重要，可以確保一個(gè)頻率的相位恰好在最后一個(gè)頻率的相位停止的地方出現(xiàn)。每個(gè)頻率的一個(gè)完整周期也是每一位完成的。

Vivado 中的邏輯設(shè)計(jì)

由于本演示中只關(guān)注發(fā)送器端，為了處理符號(hào)映射器邏輯可能在 MM2S 讀取中對(duì)來自 DDR 內(nèi)存的數(shù)據(jù)流施加的背壓，將帶有 FSK 符號(hào)映射器的 sin LUT 放置在 AXIS 數(shù)據(jù) FIFO 和 DAC 控制器 IP 之間。這樣，F(xiàn)IFO 可以完成從內(nèi)存的 MM2S 傳輸，當(dāng)符號(hào)映射器邏輯每比特輸出一個(gè)周期的相應(yīng)頻率值時(shí)，AXI DMA 不會(huì)被鎖定tdata。

代碼如下：

`timescale1ns/1ps

modulesin_lut(
inputclk,
inputrst,
input[8:0]sel,
output[15:0]DAC_code
);

reg[15:0]DAC_code;

always@(posedgeclk)
begin
if(rst==1'b0)
begin
end
else
begin
case(sel)
9'd0:DAC_code=16'h0000;
9'd1:DAC_code=16'h01C8;
9'd2:DAC_code=16'h0390;
9'd3:DAC_code=16'h0558;
9'd4:DAC_code=16'h0724;
9'd5:DAC_code=16'h08EC;
9'd6:DAC_code=16'h0AB0;
9'd7:DAC_code=16'h0C78;
9'd8:DAC_code=16'h0E3C;
9'd9:DAC_code=16'h1004;
9'd10:DAC_code=16'h11C4;
9'd11:DAC_code=16'h1388;
9'd12:DAC_code=16'h1548;
9'd13:DAC_code=16'h1708;
9'd14:DAC_code=16'h18C4;
9'd15:DAC_code=16'h1A7C;
9'd16:DAC_code=16'h1C38;
9'd17:DAC_code=16'h1DEC;
9'd18:DAC_code=16'h1FA0;
9'd19:DAC_code=16'h2154;
9'd20:DAC_code=16'h2304;
9'd21:DAC_code=16'h24B0;
9'd22:DAC_code=16'h2658;
9'd23:DAC_code=16'h2800;
9'd24:DAC_code=16'h29A4;
9'd25:DAC_code=16'h2B44;
9'd26:DAC_code=16'h2CE0;
9'd27:DAC_code=16'h2E78;
9'd28:DAC_code=16'h3010;
9'd29:DAC_code=16'h31A0;
9'd30:DAC_code=16'h3330;
9'd31:DAC_code=16'h34B8;
9'd32:DAC_code=16'h3640;
9'd33:DAC_code=16'h37C0;
9'd34:DAC_code=16'h3940;
9'd35:DAC_code=16'h3AB8;
9'd36:DAC_code=16'h3C2C;
9'd37:DAC_code=16'h3D9C;
9'd38:DAC_code=16'h3F08;
9'd39:DAC_code=16'h406C;
9'd40:DAC_code=16'h41D0;
9'd41:DAC_code=16'h432C;
9'd42:DAC_code=16'h4480;
9'd43:DAC_code=16'h45D0;
9'd44:DAC_code=16'h471C;
9'd45:DAC_code=16'h4864;
9'd46:DAC_code=16'h49A4;
9'd47:DAC_code=16'h4AE0;
9'd48:DAC_code=16'h4C14;
9'd49:DAC_code=16'h4D44;
9'd50:DAC_code=16'h4E6C;
9'd51:DAC_code=16'h4F90;
9'd52:DAC_code=16'h50AC;
9'd53:DAC_code=16'h51C4;
9'd54:DAC_code=16'h52D4;
9'd55:DAC_code=16'h53DC;
9'd56:DAC_code=16'h54E0;
9'd57:DAC_code=16'h55DC;
9'd58:DAC_code=16'h56D4;
9'd59:DAC_code=16'h57C0;
9'd60:DAC_code=16'h58A8;
9'd61:DAC_code=16'h598C;
9'd62:DAC_code=16'h5A64;
9'd63:DAC_code=16'h5B38;
9'd64:DAC_code=16'h5C04;
9'd65:DAC_code=16'h5CC8;
9'd66:DAC_code=16'h5D88;
9'd67:DAC_code=16'h5E3C;
9'd68:DAC_code=16'h5EEC;
9'd69:DAC_code=16'h5F94;
9'd70:DAC_code=16'h6034;
9'd71:DAC_code=16'h60CC;
9'd72:DAC_code=16'h6160;
9'd73:DAC_code=16'h61E8;
9'd74:DAC_code=16'h6268;
9'd75:DAC_code=16'h62E4;
9'd76:DAC_code=16'h6358;
9'd77:DAC_code=16'h63C0;
9'd78:DAC_code=16'h6424;
9'd79:DAC_code=16'h6480;
9'd80:DAC_code=16'h64D4;
9'd81:DAC_code=16'h6520;
9'd82:DAC_code=16'h6564;
9'd83:DAC_code=16'h659C;
9'd84:DAC_code=16'h65D0;
9'd85:DAC_code=16'h65FC;
9'd86:DAC_code=16'h6620;
9'd87:DAC_code=16'h663C;
9'd88:DAC_code=16'h6650;
9'd89:DAC_code=16'h665C;
9'd90:DAC_code=16'h6660;
9'd91:DAC_code=16'h665C;
9'd92:DAC_code=16'h6650;
9'd93:DAC_code=16'h663C;
9'd94:DAC_code=16'h6620;
9'd95:DAC_code=16'h65FC;
9'd96:DAC_code=16'h65D0;
9'd97:DAC_code=16'h659C;
9'd98:DAC_code=16'h6564;
9'd99:DAC_code=16'h6520;
9'd100:DAC_code=16'h64D4;
9'd101:DAC_code=16'h6480;
9'd102:DAC_code=16'h6424;
9'd103:DAC_code=16'h63C0;
9'd104:DAC_code=16'h6358;
9'd105:DAC_code=16'h62E4;
9'd106:DAC_code=16'h6268;
9'd107:DAC_code=16'h61E8;
9'd108:DAC_code=16'h6160;
9'd109:DAC_code=16'h60CC;
9'd110:DAC_code=16'h6034;
9'd111:DAC_code=16'h5F94;
9'd112:DAC_code=16'h5EEC;
9'd113:DAC_code=16'h5E3C;
9'd114:DAC_code=16'h5D88;
9'd115:DAC_code=16'h5CC8;
9'd116:DAC_code=16'h5C04;
9'd117:DAC_code=16'h5B38;
9'd118:DAC_code=16'h5A64;
9'd119:DAC_code=16'h598C;
9'd120:DAC_code=16'h58A8;
9'd121:DAC_code=16'h57C0;
9'd122:DAC_code=16'h56D4;
9'd123:DAC_code=16'h55DC;
9'd124:DAC_code=16'h54E0;
9'd125:DAC_code=16'h53DC;
9'd126:DAC_code=16'h52D4;
9'd127:DAC_code=16'h51C4;
9'd128:DAC_code=16'h50AC;
9'd129:DAC_code=16'h4F90;
9'd130:DAC_code=16'h4E6C;
9'd131:DAC_code=16'h4D44;
9'd132:DAC_code=16'h4C14;
9'd133:DAC_code=16'h4AE0;
9'd134:DAC_code=16'h49A4;
9'd135:DAC_code=16'h4864;
9'd136:DAC_code=16'h471C;
9'd137:DAC_code=16'h45D0;
9'd138:DAC_code=16'h4480;
9'd139:DAC_code=16'h432C;
9'd140:DAC_code=16'h41D0;
9'd141:DAC_code=16'h406C;
9'd142:DAC_code=16'h3F08;
9'd143:DAC_code=16'h3D9C;
9'd144:DAC_code=16'h3C2C;
9'd145:DAC_code=16'h3AB8;
9'd146:DAC_code=16'h3940;
9'd147:DAC_code=16'h37C0;
9'd148:DAC_code=16'h3640;
9'd149:DAC_code=16'h34B8;
9'd150:DAC_code=16'h3330;
9'd151:DAC_code=16'h31A0;
9'd152:DAC_code=16'h3010;
9'd153:DAC_code=16'h2E78;
9'd154:DAC_code=16'h2CE0;
9'd155:DAC_code=16'h2B44;
9'd156:DAC_code=16'h29A4;
9'd157:DAC_code=16'h2800;
9'd158:DAC_code=16'h2658;
9'd159:DAC_code=16'h24B0;
9'd160:DAC_code=16'h2304;
9'd161:DAC_code=16'h2154;
9'd162:DAC_code=16'h1FA0;
9'd163:DAC_code=16'h1DEC;
9'd164:DAC_code=16'h1C38;
9'd165:DAC_code=16'h1A7C;
9'd166:DAC_code=16'h18C4;
9'd167:DAC_code=16'h1708;
9'd168:DAC_code=16'h1548;
9'd169:DAC_code=16'h1388;
9'd170:DAC_code=16'h11C4;
9'd171:DAC_code=16'h1004;
9'd172:DAC_code=16'h0E3C;
9'd173:DAC_code=16'h0C78;
9'd174:DAC_code=16'h0AB0;
9'd175:DAC_code=16'h08EC;
9'd176:DAC_code=16'h0724;
9'd177:DAC_code=16'h0558;
9'd178:DAC_code=16'h0390;
9'd179:DAC_code=16'h01C8;
9'd180:DAC_code=16'h0000;
9'd181:DAC_code=16'hFE37;
9'd182:DAC_code=16'hFC6F;
9'd183:DAC_code=16'hFAA7;
9'd184:DAC_code=16'hF8DB;
9'd185:DAC_code=16'hF713;
9'd186:DAC_code=16'hF54F;
9'd187:DAC_code=16'hF387;
9'd188:DAC_code=16'hF1C3;
9'd189:DAC_code=16'hEFFB;
9'd190:DAC_code=16'hEE3B;
9'd191:DAC_code=16'hEC77;
9'd192:DAC_code=16'hEAB7;
9'd193:DAC_code=16'hE8F7;
9'd194:DAC_code=16'hE73B;
9'd195:DAC_code=16'hE583;
9'd196:DAC_code=16'hE3C7;
9'd197:DAC_code=16'hE213;
9'd198:DAC_code=16'hE05F;
9'd199:DAC_code=16'hDEAB;
9'd200:DAC_code=16'hDCFB;
9'd201:DAC_code=16'hDB4F;
9'd202:DAC_code=16'hD9A7;
9'd203:DAC_code=16'hD7FF;
9'd204:DAC_code=16'hD65B;
9'd205:DAC_code=16'hD4BB;
9'd206:DAC_code=16'hD31F;
9'd207:DAC_code=16'hD187;
9'd208:DAC_code=16'hCFEF;
9'd209:DAC_code=16'hCE5F;
9'd210:DAC_code=16'hCCCF;
9'd211:DAC_code=16'hCB47;
9'd212:DAC_code=16'hC9BF;
9'd213:DAC_code=16'hC83F;
9'd214:DAC_code=16'hC6BF;
9'd215:DAC_code=16'hC547;
9'd216:DAC_code=16'hC3D3;
9'd217:DAC_code=16'hC263;
9'd218:DAC_code=16'hC0F7;
9'd219:DAC_code=16'hBF93;
9'd220:DAC_code=16'hBE2F;
9'd221:DAC_code=16'hBCD3;
9'd222:DAC_code=16'hBB7F;
9'd223:DAC_code=16'hBA2F;
9'd224:DAC_code=16'hB8E3;
9'd225:DAC_code=16'hB79B;
9'd226:DAC_code=16'hB65B;
9'd227:DAC_code=16'hB51F;
9'd228:DAC_code=16'hB3EB;
9'd229:DAC_code=16'hB2BB;
9'd230:DAC_code=16'hB193;
9'd231:DAC_code=16'hB06F;
9'd232:DAC_code=16'hAF53;
9'd233:DAC_code=16'hAE3B;
9'd234:DAC_code=16'hAD2B;
9'd235:DAC_code=16'hAC23;
9'd236:DAC_code=16'hAB1F;
9'd237:DAC_code=16'hAA23;
9'd238:DAC_code=16'hA92B;
9'd239:DAC_code=16'hA83F;
9'd240:DAC_code=16'hA757;
9'd241:DAC_code=16'hA673;
9'd242:DAC_code=16'hA59B;
9'd243:DAC_code=16'hA4C7;
9'd244:DAC_code=16'hA3FB;
9'd245:DAC_code=16'hA337;
9'd246:DAC_code=16'hA277;
9'd247:DAC_code=16'hA1C3;
9'd248:DAC_code=16'hA113;
9'd249:DAC_code=16'hA06B;
9'd250:DAC_code=16'h9FCB;
9'd251:DAC_code=16'h9F33;
9'd252:DAC_code=16'h9E9F;
9'd253:DAC_code=16'h9E17;
9'd254:DAC_code=16'h9D97;
9'd255:DAC_code=16'h9D1B;
9'd256:DAC_code=16'h9CA7;
9'd257:DAC_code=16'h9C3F;
9'd258:DAC_code=16'h9BDB;
9'd259:DAC_code=16'h9B7F;
9'd260:DAC_code=16'h9B2B;
9'd261:DAC_code=16'h9ADF;
9'd262:DAC_code=16'h9A9B;
9'd263:DAC_code=16'h9A63;
9'd264:DAC_code=16'h9A2F;
9'd265:DAC_code=16'h9A03;
9'd266:DAC_code=16'h99DF;
9'd267:DAC_code=16'h99C3;
9'd268:DAC_code=16'h99AF;
9'd269:DAC_code=16'h99A3;
9'd270:DAC_code=16'h999F;
9'd271:DAC_code=16'h99A3;
9'd272:DAC_code=16'h99AF;
9'd273:DAC_code=16'h99C3;
9'd274:DAC_code=16'h99DF;
9'd275:DAC_code=16'h9A03;
9'd276:DAC_code=16'h9A2F;
9'd277:DAC_code=16'h9A63;
9'd278:DAC_code=16'h9A9B;
9'd279:DAC_code=16'h9ADF;
9'd280:DAC_code=16'h9B2B;
9'd281:DAC_code=16'h9B7F;
9'd282:DAC_code=16'h9BDB;
9'd283:DAC_code=16'h9C3F;
9'd284:DAC_code=16'h9CA7;
9'd285:DAC_code=16'h9D1B;
9'd286:DAC_code=16'h9D97;
9'd287:DAC_code=16'h9E17;
9'd288:DAC_code=16'h9E9F;
9'd289:DAC_code=16'h9F33;
9'd290:DAC_code=16'h9FCB;
9'd291:DAC_code=16'hA06B;
9'd292:DAC_code=16'hA113;
9'd293:DAC_code=16'hA1C3;
9'd294:DAC_code=16'hA277;
9'd295:DAC_code=16'hA337;
9'd296:DAC_code=16'hA3FB;
9'd297:DAC_code=16'hA4C7;
9'd298:DAC_code=16'hA59B;
9'd299:DAC_code=16'hA673;
9'd300:DAC_code=16'hA757;
9'd301:DAC_code=16'hA83F;
9'd302:DAC_code=16'hA92B;
9'd303:DAC_code=16'hAA23;
9'd304:DAC_code=16'hAB1F;
9'd305:DAC_code=16'hAC23;
9'd306:DAC_code=16'hAD2B;
9'd307:DAC_code=16'hAE3B;
9'd308:DAC_code=16'hAF53;
9'd309:DAC_code=16'hB06F;
9'd310:DAC_code=16'hB193;
9'd311:DAC_code=16'hB2BB;
9'd312:DAC_code=16'hB3EB;
9'd313:DAC_code=16'hB51F;
9'd314:DAC_code=16'hB65B;
9'd315:DAC_code=16'hB79B;
9'd316:DAC_code=16'hB8E3;
9'd317:DAC_code=16'hBA2F;
9'd318:DAC_code=16'hBB7F;
9'd319:DAC_code=16'hBCD3;
9'd320:DAC_code=16'hBE2F;
9'd321:DAC_code=16'hBF93;
9'd322:DAC_code=16'hC0F7;
9'd323:DAC_code=16'hC263;
9'd324:DAC_code=16'hC3D3;
9'd325:DAC_code=16'hC547;
9'd326:DAC_code=16'hC6BF;
9'd327:DAC_code=16'hC83F;
9'd328:DAC_code=16'hC9BF;
9'd329:DAC_code=16'hCB47;
9'd330:DAC_code=16'hCCCF;
9'd331:DAC_code=16'hCE5F;
9'd332:DAC_code=16'hCFEF;
9'd333:DAC_code=16'hD187;
9'd334:DAC_code=16'hD31F;
9'd335:DAC_code=16'hD4BB;
9'd336:DAC_code=16'hD65B;
9'd337:DAC_code=16'hD7FF;
9'd338:DAC_code=16'hD9A7;
9'd339:DAC_code=16'hDB4F;
9'd340:DAC_code=16'hDCFB;
9'd341:DAC_code=16'hDEAB;
9'd342:DAC_code=16'hE05F;
9'd343:DAC_code=16'hE213;
9'd344:DAC_code=16'hE3C7;
9'd345:DAC_code=16'hE583;
9'd346:DAC_code=16'hE73B;
9'd347:DAC_code=16'hE8F7;
9'd348:DAC_code=16'hEAB7;
9'd349:DAC_code=16'hEC77;
9'd350:DAC_code=16'hEE3B;
9'd351:DAC_code=16'hEFFB;
9'd352:DAC_code=16'hF1C3;
9'd353:DAC_code=16'hF387;
9'd354:DAC_code=16'hF54F;
9'd355:DAC_code=16'hF713;
9'd356:DAC_code=16'hF8DB;
9'd357:DAC_code=16'hFAA7;
9'd358:DAC_code=16'hFC6F;
9'd359:DAC_code=16'hFE37;
9'd360:DAC_code=16'h0000;
default:DAC_code=16'h0000;
endcase
end
end

endmodule

由于 sin LUT 的 case 語句中的選擇值是正弦波單位圓的每個(gè) 360 度值，因此計(jì)數(shù)器從 0 到 360 遞增的速度最終設(shè)置了輸出正弦波的頻率。

sin LUT 上方的邏輯中需要三個(gè)計(jì)數(shù)器：一個(gè)計(jì)數(shù)器用于對(duì) sin LUT 選擇從 0 到 359 的度數(shù)進(jìn)行計(jì)數(shù)，一個(gè)計(jì)數(shù)器用于計(jì)算頻率 0 的增量之間的延遲，以及一個(gè)計(jì)數(shù)器用于計(jì)算頻率 0 的增量之間的延遲。頻率 1.

always@(posedgeclk)
begin
if(rst==1'b0)
begin
degree_cntr<=?9'd0;
????????????????degree_cntr_done?<=?1'b0;?
????????????end
????????else?if?(incr_degree_cntr?==?1'b1)
????????????begin
????????????????if?(degree_cntr?

	

	還需要一個(gè)并行到串行轉(zhuǎn)換器，通過 MM2S 傳輸從 DDR 發(fā)出的數(shù)據(jù)包的 AXI Stream 接口獲取 32 位數(shù)據(jù)，并將其串行化，可以通過 MM2S 傳輸輸出該位各自頻率的一個(gè)周期。 DAC一次。這就是 2-FSK 的局限性暴露出來的地方：一次只能傳輸一位。

	
always@(tdata_sel_cntr)
begin
case(tdata_sel_cntr)
32'd0:
begin
current_tx_bit<=?tdata[0];
????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd1???:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[1];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd2???:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[2];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd3???:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[3];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd4???:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[4];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd5???:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[5];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd6???:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[6];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd7???:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[7];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd8???:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[8];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd9???:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[9];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd10??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[10];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd11??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[11];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd12??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[12];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd13??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[13];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd14??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[14];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd15??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[15];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd16??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[16];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd17??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[17];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd18??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[18];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd19??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[19];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd20??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[20];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd21??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[21];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd22??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[22];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd23??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[23];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd24??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[24];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd25??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[25];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd26??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[26];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd27??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[27];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd28??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[28];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd29??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[29];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd30??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[30];
?????????????????????tx_pkt_done?<=?1'b0;
????????????????end?
????????????32'd31??:?
????????????????begin
?????????????????????current_tx_bit?<=?tdata[31];
?????????????????????tx_pkt_done?<=?1'b1;
????????????????end?
????????????default?:?
????????????????begin
????????????????????current_tx_bit?<=?1'b0;
????????????????????tx_pkt_done?<=?1'b0;
????????????????end
????????endcase?
????end

always?@?(posedge?clk)
????begin?
????????if?(current_tx_bit?==?1'b1)
????????????period?<=?T1_period;
????????else
????????????period?<=?T0_period;
????end


	

	最后，AXI Stream 接口只需要圍繞上述邏輯，使用從接口接收來自 AXIS FIFO 的數(shù)據(jù)，并使用主接口將數(shù)據(jù)輸出到 DAC 控制器。

	
`timescale1ns/1ps

modulesin_axis(
inputclk,
inputreset,
input[31:0]s_axis_tdata,
input[3:0]s_axis_tkeep,
inputs_axis_tlast,
outputregs_axis_tready,
inputs_axis_tvalid,
outputreg[31:0]m_axis_tdata,
outputreg[3:0]m_axis_tkeep,
outputregm_axis_tlast,
inputm_axis_tready,
outputregm_axis_tvalid,
output[2:0]state_reg
);

sin_smsin_sm_i(
.clk(clk),
.rst(reset),
.tdata_slave(tdata_slave),
.tdata_master(tdata_master),
.tx_pkt_done(tx_pkt_done)
);


regtlast;
reg[2:0]state_reg;

wiretx_pkt_done;
wire[31:0]tdata_master;
reg[31:0]tdata_slave;


parameterinit=3'd0;
parameterSetSlaveTready=3'd1;
parameterCheckSlaveTvalid=3'd2;
parameterProcessTdata=3'd3;
parameterCheckTlast=3'd4;

always@(posedgeclk)
begin
//Defaultoutputs
m_axis_tvalid<=?1'b0;
????????????
????????????if?(reset?==?1'b0)
????????????????begin
????????????????????tlast?<=?1'b0;
????????????????????tdata_slave[31:0]?<=?32'd0;
????????????????????s_axis_tready?<=?1'b0;
????????????????????m_axis_tdata[31:0]?<=?32'd0;
????????????????????m_axis_tkeep?<=?4'h0;
????????????????????m_axis_tlast?<=?1'b0;
????????????????????state_reg?<=?init;
????????????????end
????????????else
????????????????begin
????????????????
????????????????????case(state_reg)?
????????????????????????init?:?//?0?
????????????????????????????begin
????????????????????????????????tlast?<=?1'b0;
????????????????????????????????tdata_slave[31:0]?<=?32'd0;
????????????????????????????????s_axis_tready?<=?1'b0;
????????????????????????????????m_axis_tdata[31:0]?<=?32'd0;
????????????????????????????????m_axis_tkeep?<=?4'h0;
????????????????????????????????m_axis_tlast?<=?1'b0;
????????????????????????????????state_reg?<=?SetSlaveTready;
????????????????????????????end?
????????????????????????????
????????????????????????SetSlaveTready?:?//?1
????????????????????????????begin
????????????????????????????????s_axis_tready?<=?1'b1;
????????????????????????????????state_reg?<=?CheckSlaveTvalid;
????????????????????????????end?
????????????????????????????
????????????????????????CheckSlaveTvalid?:?//?2
????????????????????????????begin
????????????????????????????????if?(s_axis_tkeep?==?4'hf?&&?s_axis_tvalid?==?1'b1)
????????????????????????????????????begin
????????????????????????????????????????s_axis_tready?<=?1'b0;
????????????????????????????????????????tlast?<=?s_axis_tlast;
????????????????????????????????????????tdata_slave[31:0]?<=?s_axis_tdata[31:0];
????????????????????????????????????????state_reg?<=?ProcessTdata;
????????????????????????????????????end
????????????????????????????????else
????????????????????????????????????begin?
????????????????????????????????????????tdata_slave[31:0]?<=?32'd0;
????????????????????????????????????????state_reg?<=?CheckSlaveTvalid;
????????????????????????????????????end?
????????????????????????????end
????????????????????????????
????????????????????????ProcessTdata?:?//?3
????????????????????????????begin?
????????????????????????????????m_axis_tkeep?<=?4'hf;
????????????????????????????????m_axis_tlast?<=?tlast;
????????????????????????????????m_axis_tvalid?<=?1'b1;
????????????????????????????????m_axis_tdata[31:0]?<=?tdata_master[31:0];
????????????????????????????????
????????????????????????????????if?(m_axis_tready?==?1'b1?&&?tx_pkt_done?==?1'b1)
????????????????????????????????????begin?
????????????????????????????????????????state_reg?<=?CheckTlast;
????????????????????????????????????end?
????????????????????????????????else
????????????????????????????????????begin?
????????????????????????????????????????state_reg?<=?ProcessTdata;
????????????????????????????????????end?
????????????????????????????end
????????????????????????????
????????????????????????CheckTlast?:?//?4
????????????????????????????begin?
????????????????????????????????if?(m_axis_tlast?==?1'b1)
????????????????????????????????????begin????
????????????????????????????????????????state_reg?<=?init;
????????????????????????????????????end
????????????????????????????????else?if?(m_axis_tready?==?1'b1)
????????????????????????????????????begin
????????????????????????????????????????state_reg?<=?SetSlaveTready;
????????????????????????????????????end
????????????????????????????????else?
????????????????????????????????????begin?
????????????????????????????????????????state_reg?<=?CheckTlast;
????????????????????????????????????end?
????????????????????????????end?
????????????????????????????
????????????????????endcase?
????????????????end
????????end
endmodule


	

	完整的代碼見最后。

	Vitis 軟件

	由于生成正弦波的所有邏輯都是在 Verilog 的 HDL 中處理的，因此 C 代碼中唯一剩下的就是控制 MM2S 傳輸（源文件也附在下面）：

	
intmain()
{
init_platform();

XAxiDma_Config*CfgPtr;//DMAconfigurationpointer
intStatus,Index;
u8*TxBufferPtr;

TxBufferPtr=(u8*)TX_BUFFER_BASE;

for(Index=0;Index

	

	測(cè)試設(shè)備

	為了驗(yàn)證模擬輸出，將其通道 1 連接到示波器通道 1，并在主機(jī) PC 上啟動(dòng) WaveForms 來查看它。

	然后，在 Vitis 中啟動(dòng) C 應(yīng)用程序的調(diào)試，并在 MM2S 傳輸開始之前設(shè)置了斷點(diǎn)：

	

	由于將DAC設(shè)置為低增益模式，因此峰值輸出值約為 1.0v。在 WaveForms 的 Scope 選項(xiàng)卡中，為超過 100mV 的上升沿設(shè)置電平觸發(fā)器，然后單擊Run 。

	得到 1 和 0 兩個(gè)不同頻率值的清晰輸出：

	

	正如我上面提到的，這只是符號(hào)映射器的一個(gè)非常簡化的版本，目的是為了以更實(shí)用、更實(shí)際的方式克服 SDR 設(shè)計(jì)入門的困難。兩個(gè)不同頻率的周期計(jì)數(shù)器是查看輸出結(jié)果的良好起點(diǎn)。

	






	審核編輯：劉清