1// Chuck Benz, Hollis, NH Copyright (c)2002 2// 3// The information and description contained herein is the 4// property of Chuck Benz. 5// 6// Permission is granted for any reuse of this information 7// and description as long as this copyright notice is 8// preserved. Modifications may be made as long as this 9// notice is preserved. 10 11// 11-OCT-2002: updated with clearer messages, and checking decodeout 12 13`timescale 1ns / 1ns 14module test_8b10b ; 15 reg [29:0] code8b10b [0:267] ; 16 reg [8:0] testin ; 17 reg dispin ; 18 reg [10:0] i ; 19 wire [9:0] testout ; 20 wire dispout, decodedisp, decodeerr, disperr ; 21 wire [8:0] decodeout ; 22 // My data file is 30 columns. Column 1 becomes [29], 2 becomes [28], etc.. 23 // code[0] is last Column (30) 24 // First column, [29] is K indication 25 // columns 2:9, [28:21], are data byte, aka 'm' and 'n' of Dm.n 26 // columns 10:19, [20:11] are 10b symbol if starting disparity was negative, 0 27 // columns 20:29, [10:1] are 10b symbol if starting disparity was positive, 1 28 // column 30, [0], is a 1 if symbol results in a disparity flip 29 // 0 for a balanced symbol (5 '1's, 5 '0's). 30 31 wire [29:0] code = code8b10b[i] ; 32 wire [9:0] expect_0_disp = {code[11], code[12], code[13], code[14], code[15], 33 code[16], code[17], code[18], code[19], code[20]} ; 34 wire [9:0] expect_1_disp = {code[1], code[2], code[3], code[4], code[5], 35 code[6], code[7], code[8], code[9], code[10]} ; 36 37 reg [1023:0] legal ; // mark every used 10b symbol as legal, leave rest marked as not 38 reg [2047:0] okdisp ; // now mark every used combination of symbol and starting disparity 39 reg [8:0] mapcode [1023:0] ; 40 reg [10:0] codedisp0, codedisp1 ; 41 reg [9:0] decodein ; 42 reg decdispin ; 43 integer errors ; 44 45 encode_8b10b DUTE (testin, dispin, testout, dispout) ; 46 decode_8b10b DUTD (decodein, decdispin, decodeout, decodedisp, decodeerr, disperr) ; 47 48 always @ (code) testin = code[29:21] ; 49 50 initial begin 51 errors = 0 ; 52 $readmemb ("8b10b_a.mem", code8b10b) ; 53 //$vcdpluson ; 54 $dumpvars (0); 55 $display ("\n\nFirst, test by trying all 268 (256 Dx.y and 12 Kx.y)") ; 56 $display ("valid inputs, with both + and - starting disparity."); 57 $display ("We check that the encoder output and ending disparity is correct."); 58 $display ("We also check that the decoder matches."); 59 for (i = 0 ; i < 268 ; i = i + 1) begin 60 // testin = code[29:21] ; 61 dispin = 0 ; 62 #1 63 decodein = testout ; 64 decdispin = dispin ; 65 #1 66// $display ("%b %b %b %b *%b*", dispin, testin, testout, {dispout, DUTD.disp6a, DUTD.disp6a2, DUTD.disp6a0, DUTD.disp6a2}, decodeout,, decodedisp,, DUTD.k28,, DUTD.disp6b) ; 67 if (testout != expect_0_disp) 68 $display ("bad code0 %b %b %b %b %b", dispin, testin, dispout, testout, expect_0_disp) ; 69 if (dispout != (dispin ^ code[0])) 70 $display ("bad disp0 %b %b %b %b %b", dispin, testin, dispout, testout, (dispin ^ code[0])) ; 71 if (0 != (9'b1_1111_1111 & (testin ^ decodeout))) 72 $display ("diff in abcdefghk decode, %b %b %b %b %b", dispin, testin, dispout, testout, decodeout) ; 73 if (decodedisp != dispout) 74 $display ("diff in decoder disp out, %b %b %b %b %b", dispin, testin, dispout, testout, decodeout) ; 75 if (decodeerr) $display ("decode error asserted improperly, %b %b %b %b %b", dispin, testin, dispout, testout, decodeout) ; 76 if ((testout != expect_0_disp) | decodeerr | 77 (dispout != (dispin ^ code[0])) | (decodedisp != dispout)) 78 errors = errors + 1 ; 79 80 dispin = 1 ; 81 #1 82 decodein = testout ; 83 decdispin = dispin ; 84 #1 85// $display ("%b %b %b %b *%b*", dispin, testin, testout, {dispout, DUTD.disp6a, DUTD.disp6a2, DUTD.disp6a0, DUTD.disp6a2, DUTD.fghjp31, DUTD.feqg, DUTD.heqj, DUTD.fghj22, DUTD.fi, DUTD.gi, DUTD.hi, DUTD.ji, DUTD.dispout}, decodeout,, decodedisp,, DUTD.k28,, DUTD.disp6b) ; 86 if (testout != expect_1_disp) 87 $display ("bad code1 %b %b %b %b %b", dispin, testin, dispout, testout, expect_1_disp) ; 88 if (dispout != (dispin ^ code[0])) 89 $display ("bad disp1 %b %b %b %b %b", dispin, testin, dispout, testout, (dispin ^ code[0])) ; 90 if (0 != (9'b1_1111_1111 & (testin ^ decodeout))) 91 $display ("diff in abcdefghk decode, %b %b %b %b %b", dispin, testin, dispout, testout, decodeout) ; 92 if (decodedisp != dispout) 93 $display ("diff in decoder disp out, %b %b %b %b %b", dispin, testin, dispout, testout, decodeout) ; 94 if (decodeerr) $display ("decode error asserted improperly, %b %b %b %b %b", dispin, testin, dispout, testout, decodeout) ; 95 if ((testout != expect_1_disp) | decodeerr | 96 (dispout != (dispin ^ code[0])) | (decodedisp != dispout)) 97 errors = errors + 1 ; 98 end 99 $display ("%d errors in that testing.\n", errors) ; 100 101 // Now, having verified all legal codes, lets run some illegal codes 102 // at the decoder... how to figure illegal codes ? 2048 possible cases, 103 // lets mark the OK ones... 104 legal = 0 ; 105 okdisp = 0 ; 106 for (i = 0 ; i < 268 ; i = i + 1) begin 107 #1 108// $display ("i=%d: %b %b %d %d %x %x", i, expect_0_disp, expect_1_disp, expect_0_disp, expect_1_disp, expect_0_disp, expect_1_disp) ; 109 legal[expect_0_disp] = 1 ; 110 legal[expect_1_disp] = 1 ; 111 codedisp0 = expect_0_disp ; 112 codedisp1 = {1'b1, expect_1_disp} ; 113 okdisp[codedisp0] = 1 ; 114 okdisp[codedisp1] = 1 ; 115 mapcode[expect_0_disp] = code[29:21] ; 116 mapcode[expect_1_disp] = code[29:21] ; 117 end 118 119 $display ("Now lets test all (legal and illegal) codes into the decoder."); 120 $display ("checking all possible decode inputs") ; 121 for (i = 0 ; i < 1024 ; i = i + 1) begin 122 decodein = i ; 123 decdispin = 0 ; 124 codedisp1 = 1024 | i ; 125 #1 126 if (((legal[i] == 0) & (decodeerr != 1)) | 127 (legal[i] & (mapcode[i] != decodeout)) | 128 (legal[i] & (disperr != !okdisp[i]))) 129 $display ("10b:%b start disp:%b 8b:%b end disp:%b codevio:%b dispvio:%b known code:%b used disp:", 130 decodein, decdispin, decodeout, decodedisp, decodeerr, disperr, legal[i], okdisp[i]) ; 131 if ((legal[i] == 0) & (decodeerr != 1)) $display ("ERR: decoderr should be 1") ; 132 if (legal[i] & (mapcode[i] != decodeout)) $display ("ERR: decode output incorrect") ; 133 if (legal[i] & (disperr != 1) & !okdisp[i]) $display ("ERR: disp err should be asserted") ; 134 else if (legal[i] & (disperr != 0) & okdisp[i]) 135 $display ("ERR: disp err should not be asserted") ; 136 137 if (((legal[i] == 0) & (decodeerr != 1)) | 138 (legal[i] & !disperr & !okdisp[i]) | 139 (legal[i] & (mapcode[i] != decodeout)) | 140 (legal[i] & disperr & okdisp[i])) 141 errors = errors + 1 ; 142 143 decdispin = 1 ; 144 #1 145 if (((legal[i] == 0) & (decodeerr != 1)) | 146 (legal[i] & (mapcode[i] != decodeout)) | 147 (legal[i] & (disperr != !okdisp[i|1024]))) 148 $display ("10b:%b start disp:%b 8b:%b end disp:%b codevio:%b dispvio:%b known code:%b used disp:", 149 decodein, decdispin, decodeout, decodedisp, decodeerr, disperr, legal[i], okdisp[i|1024]) ; 150 if ((legal[i] == 0) & (decodeerr != 1)) $display ("ERR: decoderr should be 1") ; 151 if (legal[i] & (mapcode[i] != decodeout)) $display ("ERR: decode output incorrect") ; 152 if (legal[i] & (disperr != 1) & !okdisp[i|1024]) $display ("ERR: disp err should be asserted") ; 153 else if (legal[i] & (disperr != 0) & okdisp[i|1024]) 154 $display ("ERR: disp err should not be asserted") ; 155 if (((legal[i] == 0) & (decodeerr != 1)) | 156 (legal[i] & !disperr & !okdisp[i|1024]) | 157 (legal[i] & (mapcode[i] != decodeout)) | 158 (legal[i] & disperr & okdisp[i|1024])) 159 errors = errors + 1 ; 160 end // for (i = 0 ; i < 1024 ; i = i + 1) 161 162 $display ("\nDone testing decoder.\n") ; 163 $display ("Total error count: %d", errors); 164 if (errors == 0) $display ("Congratulations!\n"); 165 $finish ; 166 end // initial begin 167 168endmodule 169