1 EESchema Schematic File Version 4 2 LIBS:AcornElectronMainboard-cache 3 EELAYER 26 0 4 EELAYER END 5 $Descr A4 8268 11693 portrait 6 encoding utf-8 7 Sheet 1 9 8 Title "Acorn Electron Mainboard" 9 Date "" 10 Rev "" 11 Comp "" 12 Comment1 "" 13 Comment2 "" 14 Comment3 "" 15 Comment4 "" 16 $EndDescr 17 $Comp 18 L AcornElectron:ULA12C021 IC1 19 U 1 1 61CC86CA 20 P 4300 4100 21 F 0 "IC1" H 4300 6750 50 0000 C CNN 22 F 1 "ULA12C021" H 4300 6650 50 0000 C CNN 23 F 2 "" H 4300 4100 50 0001 C CNN 24 F 3 "" H 4300 4100 50 0001 C CNN 25 1 4300 4100 26 1 0 0 -1 27 $EndComp 28 Text Label 2900 3900 2 50 ~ 0 29 A0 30 Text Label 2900 4300 2 50 ~ 0 31 A4 32 Text Label 2900 4400 2 50 ~ 0 33 A5 34 Text Label 2900 4500 2 50 ~ 0 35 A6 36 Text Label 2900 4600 2 50 ~ 0 37 A7 38 Text Label 2900 4700 2 50 ~ 0 39 A8 40 Text Label 2900 4800 2 50 ~ 0 41 A9 42 Text Label 2900 4900 2 50 ~ 0 43 A10 44 Text Label 2900 5000 2 50 ~ 0 45 A11 46 Text Label 2900 5100 2 50 ~ 0 47 A12 48 Text Label 2900 5200 2 50 ~ 0 49 A13 50 Text Label 2900 5300 2 50 ~ 0 51 A14 52 Text Label 2900 4000 2 50 ~ 0 53 A1 54 Text Label 2900 4100 2 50 ~ 0 55 A2 56 Text Label 2900 4200 2 50 ~ 0 57 A3 58 Text Label 2900 5400 2 50 ~ 0 59 A15 60 Wire Bus Line 61 2000 3800 2100 3800 62 Entry Wire Line 63 2100 3800 2200 3900 64 Entry Wire Line 65 2100 4000 2200 4100 66 Entry Wire Line 67 2100 4100 2200 4200 68 Entry Wire Line 69 2100 4200 2200 4300 70 Entry Wire Line 71 2100 4300 2200 4400 72 Entry Wire Line 73 2100 4400 2200 4500 74 Entry Wire Line 75 2100 4500 2200 4600 76 Entry Wire Line 77 2100 4600 2200 4700 78 Entry Wire Line 79 2100 4700 2200 4800 80 Entry Wire Line 81 2100 4800 2200 4900 82 Entry Wire Line 83 2100 4900 2200 5000 84 Entry Wire Line 85 2100 5000 2200 5100 86 Entry Wire Line 87 2100 5100 2200 5200 88 Entry Wire Line 89 2100 5200 2200 5300 90 Entry Wire Line 91 2100 5300 2200 5400 92 Entry Wire Line 93 2100 3900 2200 4000 94 Wire Wire Line 95 2200 3900 2900 3900 96 Wire Wire Line 97 2200 4000 2900 4000 98 Wire Wire Line 99 2200 4100 2900 4100 100 Wire Wire Line 101 2200 4200 2900 4200 102 Wire Wire Line 103 2200 4300 2900 4300 104 Wire Wire Line 105 2200 4400 2900 4400 106 Wire Wire Line 107 2200 4500 2900 4500 108 Wire Wire Line 109 2200 4600 2900 4600 110 Wire Wire Line 111 2200 4700 2900 4700 112 Wire Wire Line 113 2200 4800 2900 4800 114 Wire Wire Line 115 2200 4900 2900 4900 116 Wire Wire Line 117 2200 5000 2900 5000 118 Wire Wire Line 119 2200 5100 2900 5100 120 Wire Wire Line 121 2200 5200 2900 5200 122 Wire Wire Line 123 2200 5300 2900 5300 124 Entry Wire Line 125 2100 2300 2200 2400 126 Entry Wire Line 127 2100 2400 2200 2500 128 Entry Wire Line 129 2100 2500 2200 2600 130 Entry Wire Line 131 2100 2600 2200 2700 132 Entry Wire Line 133 2100 2700 2200 2800 134 Entry Wire Line 135 2100 2800 2200 2900 136 Entry Wire Line 137 2100 2900 2200 3000 138 Entry Wire Line 139 2100 3000 2200 3100 140 Wire Wire Line 141 2200 2400 2900 2400 142 Wire Wire Line 143 2200 2500 2900 2500 144 Wire Wire Line 145 2200 2600 2900 2600 146 Wire Wire Line 147 2200 2700 2900 2700 148 Wire Wire Line 149 2200 2800 2900 2800 150 Wire Wire Line 151 2200 2900 2900 2900 152 Wire Wire Line 153 2200 3000 2900 3000 154 Wire Wire Line 155 2200 3100 2900 3100 156 Text Label 2900 2400 2 50 ~ 0 157 A0 158 Text Label 2900 2500 2 50 ~ 0 159 A1 160 Text Label 2900 2600 2 50 ~ 0 161 A2 162 Text Label 2900 2700 2 50 ~ 0 163 A3 164 Text Label 2900 2800 2 50 ~ 0 165 A4 166 Text Label 2900 2900 2 50 ~ 0 167 A5 168 Text Label 2900 3000 2 50 ~ 0 169 A6 170 Text Label 2900 3100 2 50 ~ 0 171 A7 172 Entry Wire Line 173 2100 2000 2200 2100 174 Entry Wire Line 175 2100 2100 2200 2200 176 Entry Wire Line 177 2100 2200 2200 2300 178 Wire Wire Line 179 2200 2100 2900 2100 180 Wire Wire Line 181 2200 2200 2900 2200 182 Wire Wire Line 183 2200 2300 2900 2300 184 Text Label 2900 2100 2 50 ~ 0 185 ~WE 186 Text Label 2900 2200 2 50 ~ 0 187 ~RAS 188 Text Label 2900 2300 2 50 ~ 0 189 ~CAS 190 Wire Wire Line 191 2200 2000 2900 2000 192 Wire Wire Line 193 2900 1900 2200 1900 194 Wire Wire Line 195 2900 1800 2200 1800 196 Wire Wire Line 197 2900 1700 2200 1700 198 Entry Wire Line 199 2100 1600 2200 1700 200 Entry Wire Line 201 2100 1700 2200 1800 202 Entry Wire Line 203 2100 1800 2200 1900 204 Entry Wire Line 205 2100 1900 2200 2000 206 Text Label 2900 1700 2 50 ~ 0 207 RAM0 208 Text Label 2900 1800 2 50 ~ 0 209 RAM1 210 Text Label 2900 1900 2 50 ~ 0 211 RAM2 212 Text Label 2900 2000 2 50 ~ 0 213 RAM3 214 Text Label 2900 5500 2 50 ~ 0 215 D0 216 Text Label 2900 5600 2 50 ~ 0 217 D1 218 Text Label 2900 5700 2 50 ~ 0 219 D2 220 Text Label 2900 5800 2 50 ~ 0 221 D3 222 Text Label 2900 5900 2 50 ~ 0 223 D4 224 Text Label 2900 6000 2 50 ~ 0 225 D5 226 Text Label 2900 6100 2 50 ~ 0 227 D6 228 Text Label 2900 6200 2 50 ~ 0 229 D7 230 Wire Wire Line 231 2900 3800 2300 3800 232 Wire Wire Line 233 2300 3800 2300 3700 234 Entry Wire Line 235 2100 3100 2200 3200 236 Entry Wire Line 237 2100 3200 2200 3300 238 Entry Wire Line 239 2100 3300 2200 3400 240 Entry Wire Line 241 2100 3400 2200 3500 242 Wire Wire Line 243 2200 3200 2900 3200 244 Wire Wire Line 245 2200 3300 2900 3300 246 Wire Wire Line 247 2200 3400 2900 3400 248 Wire Wire Line 249 2200 3500 2900 3500 250 $Comp 251 L Connector_Generic:Conn_01x03 PL3 252 U 1 1 61CF9DF4 253 P 1400 8900 254 F 0 "PL3" H 1320 9217 50 0000 C CNN 255 F 1 "Power" H 1320 9126 50 0000 C CNN 256 F 2 "" H 1400 8900 50 0001 C CNN 257 F 3 "~" H 1400 8900 50 0001 C CNN 258 1 1400 8900 259 -1 0 0 -1 260 $EndComp 261 Text GLabel 2800 8800 2 50 Output ~ 0 262 5V 263 Wire Wire Line 264 1600 8800 2200 8800 265 Text GLabel 2800 9300 2 50 Output ~ 0 266 0V 267 Text GLabel 2800 9800 2 50 Output ~ 0 268 -5V 269 Wire Wire Line 270 1900 9300 2100 9300 271 Wire Wire Line 272 1800 9800 2100 9800 273 Text GLabel 3800 7100 3 50 Input ~ 0 274 0V 275 Wire Wire Line 276 3800 7100 3800 6900 277 Wire Wire Line 278 3800 6900 4000 6900 279 Wire Wire Line 280 4000 6900 4000 6750 281 Connection ~ 3800 6900 282 Wire Wire Line 283 3800 6900 3800 6750 284 Text GLabel 3600 900 1 50 Input ~ 0 285 5V 286 Wire Wire Line 287 3600 900 3600 1000 288 $Comp 289 L Device:R R5 290 U 1 1 61F10DD6 291 P 3800 1250 292 F 0 "R5" H 3650 1300 50 0000 L CNN 293 F 1 "24R" H 3750 1200 50 0000 R CNN 294 F 2 "" V 3730 1250 50 0001 C CNN 295 F 3 "~" H 3800 1250 50 0001 C CNN 296 1 3800 1250 297 1 0 0 -1 298 $EndComp 299 $Comp 300 L Device:R R58 301 U 1 1 61F10E39 302 P 4000 1250 303 F 0 "R58" H 4050 1300 50 0000 L CNN 304 F 1 "24R" H 4050 1200 50 0000 L CNN 305 F 2 "" V 3930 1250 50 0001 C CNN 306 F 3 "~" H 4000 1250 50 0001 C CNN 307 1 4000 1250 308 1 0 0 -1 309 $EndComp 310 Wire Wire Line 311 3800 1550 3800 1400 312 Wire Wire Line 313 4000 1550 4000 1400 314 Wire Wire Line 315 3800 1100 3800 1000 316 Wire Wire Line 317 3800 1000 3600 1000 318 Connection ~ 3600 1000 319 Wire Wire Line 320 3600 1000 3600 1550 321 Wire Wire Line 322 4000 1100 4000 1000 323 Wire Wire Line 324 4000 1000 3800 1000 325 Connection ~ 3800 1000 326 $Comp 327 L Device:C C27 328 U 1 1 61FBBBB4 329 P 3350 1250 330 F 0 "C27" H 3250 1300 50 0000 R CNN 331 F 1 "10??F" H 3250 1200 50 0000 R CNN 332 F 2 "" H 3388 1100 50 0001 C CNN 333 F 3 "~" H 3350 1250 50 0001 C CNN 334 1 3350 1250 335 1 0 0 -1 336 $EndComp 337 Wire Wire Line 338 3600 1000 3350 1000 339 Wire Wire Line 340 3350 1000 3350 1100 341 Text GLabel 3250 1500 0 50 Input ~ 0 342 0V 343 Wire Wire Line 344 3250 1500 3350 1500 345 Wire Wire Line 346 3350 1500 3350 1400 347 $Comp 348 L Device:C Ax19 349 U 1 1 621AFB3A 350 P 2700 9050 351 F 0 "Ax19" H 2815 9096 50 0000 L CNN 352 F 1 "47nF" H 2815 9005 50 0000 L CNN 353 F 2 "" H 2738 8900 50 0001 C CNN 354 F 3 "~" H 2700 9050 50 0001 C CNN 355 1 2700 9050 356 1 0 0 -1 357 $EndComp 358 $Comp 359 L Device:C Ax1 360 U 1 1 62245E33 361 P 2600 9550 362 F 0 "Ax1" H 2715 9596 50 0000 L CNN 363 F 1 "47nF" H 2715 9505 50 0000 L CNN 364 F 2 "" H 2638 9400 50 0001 C CNN 365 F 3 "~" H 2600 9550 50 0001 C CNN 366 1 2600 9550 367 1 0 0 -1 368 $EndComp 369 $Comp 370 L Device:CP C1 371 U 1 1 62245FAE 372 P 2200 9050 373 F 0 "C1" H 2318 9096 50 0000 L CNN 374 F 1 "47??F" H 2318 9005 50 0000 L CNN 375 F 2 "" H 2238 8900 50 0001 C CNN 376 F 3 "~" H 2200 9050 50 0001 C CNN 377 1 2200 9050 378 1 0 0 -1 379 $EndComp 380 $Comp 381 L Device:CP C2 382 U 1 1 62245FF4 383 P 2100 9550 384 F 0 "C2" H 2218 9596 50 0000 L CNN 385 F 1 "10??F" H 2218 9505 50 0000 L CNN 386 F 2 "" H 2138 9400 50 0001 C CNN 387 F 3 "~" H 2100 9550 50 0001 C CNN 388 1 2100 9550 389 1 0 0 -1 390 $EndComp 391 Wire Wire Line 392 1900 9300 1900 8900 393 Wire Wire Line 394 1900 8900 1600 8900 395 Wire Wire Line 396 1800 9800 1800 9000 397 Wire Wire Line 398 2200 8900 2200 8800 399 Connection ~ 2200 8800 400 Wire Wire Line 401 2200 8800 2700 8800 402 Wire Wire Line 403 2100 9400 2100 9300 404 Connection ~ 2100 9300 405 Wire Wire Line 406 2100 9300 2200 9300 407 Wire Wire Line 408 2200 9200 2200 9300 409 Connection ~ 2200 9300 410 Wire Wire Line 411 2200 9300 2600 9300 412 Wire Wire Line 413 2100 9700 2100 9800 414 Connection ~ 2100 9800 415 Wire Wire Line 416 2100 9800 2600 9800 417 Wire Wire Line 418 2600 9800 2600 9700 419 Connection ~ 2600 9800 420 Wire Wire Line 421 2600 9800 2800 9800 422 Wire Wire Line 423 2600 9400 2600 9300 424 Connection ~ 2600 9300 425 Wire Wire Line 426 2600 9300 2700 9300 427 Wire Wire Line 428 2700 9300 2700 9200 429 Connection ~ 2700 9300 430 Wire Wire Line 431 2700 9300 2800 9300 432 Wire Wire Line 433 2700 8900 2700 8800 434 Connection ~ 2700 8800 435 Wire Wire Line 436 2700 8800 2800 8800 437 $Comp 438 L Connector_Generic:Conn_01x02 PL4 439 U 1 1 627DA4FF 440 P 1400 10100 441 F 0 "PL4" H 1320 10317 50 0000 C CNN 442 F 1 "Power" H 1320 10226 50 0000 C CNN 443 F 2 "" H 1400 10100 50 0001 C CNN 444 F 3 "~" H 1400 10100 50 0001 C CNN 445 1 1400 10100 446 -1 0 0 -1 447 $EndComp 448 Wire Wire Line 449 3600 6750 3600 7400 450 Wire Wire Line 451 3600 7400 3500 7400 452 Text Label 1600 8800 0 50 ~ 0 453 5V 454 Text Label 1600 8900 0 50 ~ 0 455 0V 456 Wire Wire Line 457 1600 9000 1800 9000 458 Text Label 1600 9000 0 50 ~ 0 459 -5V 460 Text Label 1600 10100 0 50 ~ 0 461 RETURN 462 Text Label 1600 10200 0 50 ~ 0 463 18VAC 464 Wire Wire Line 465 4600 7600 4600 6750 466 $Sheet 467 S 2800 7800 700 300 468 U 61DF4BC2 469 F0 "Clocks" 50 470 F1 "clocks.sch" 50 471 $EndSheet 472 Text GLabel 3500 7600 0 50 Input ~ 0 473 CLOCK_16MHz 474 Text GLabel 3500 7400 0 50 Input ~ 0 475 CLOCK_16MHz_DIV_13 476 $Sheet 477 S 1200 1100 700 300 478 U 61D7EEE8 479 F0 "RAM" 50 480 F1 "RAM.sch" 50 481 $EndSheet 482 Wire Bus Line 483 2100 2000 2000 2000 484 Wire Bus Line 485 2100 1600 2000 1600 486 Text GLabel 2000 1600 0 50 BiDi ~ 0 487 RAM_DATA 488 Text GLabel 2000 2000 0 50 Output ~ 0 489 RAM_ADDRESS 490 $Sheet 491 S 5800 1300 700 300 492 U 624B50A6 493 F0 "Cassette" 50 494 F1 "cassette.sch" 50 495 $EndSheet 496 Text GLabel 5800 3600 2 50 Input ~ 0 497 CASSETTE_INPUT 498 Wire Wire Line 499 5600 3600 5800 3600 500 Text GLabel 5800 1800 2 50 Output ~ 0 501 CASSETTE_OUTPUT 502 Wire Wire Line 503 5600 1800 5800 1800 504 $Sheet 505 S 5800 4200 700 300 506 U 61E9B87F 507 F0 "Sound" 50 508 F1 "sound.sch" 50 509 $EndSheet 510 Text GLabel 5800 4700 2 50 Output ~ 0 511 SOUND_OUTPUT 512 Wire Wire Line 513 5600 4700 5800 4700 514 Text GLabel 2000 10100 2 50 UnSpc ~ 0 515 POWER_AC_RETURN 516 Text GLabel 2000 10200 2 50 UnSpc ~ 0 517 POWER_18VAC 518 Wire Wire Line 519 1600 10100 2000 10100 520 Wire Wire Line 521 1600 10200 2000 10200 522 Wire Wire Line 523 3500 7600 4600 7600 524 Text GLabel 1700 6400 0 50 Output ~ 0 525 PHI_OUT 526 $Sheet 527 S 1300 7800 700 300 528 U 61FB7D7E 529 F0 "Expansion" 50 530 F1 "expansion.sch" 50 531 $EndSheet 532 Text GLabel 2000 5400 0 50 BiDi ~ 0 533 CPU_DATA 534 Wire Bus Line 535 2000 5400 2100 5400 536 Text GLabel 2000 3800 0 50 Input ~ 0 537 CPU_ADDRESS 538 Text GLabel 1700 6600 0 50 Input ~ 0 539 RnW 540 Text GLabel 2000 6500 0 50 Output ~ 0 541 ~IRQ 542 Text GLabel 2000 6300 0 50 Input ~ 0 543 ~NMI 544 Text GLabel 2700 3700 0 50 Input ~ 0 545 ~RST 546 $Sheet 547 S 1300 6800 700 300 548 U 61F2273C 549 F0 "CPU, ROM, keyboard" 50 550 F1 "CPU_ROM_KBD.sch" 50 551 $EndSheet 552 Text GLabel 2000 3100 0 50 Input ~ 0 553 KBD_DATA 554 Wire Bus Line 555 2000 3100 2100 3100 556 Wire Wire Line 557 2700 3700 2900 3700 558 Entry Wire Line 559 2100 5400 2200 5500 560 Entry Wire Line 561 2100 5500 2200 5600 562 Entry Wire Line 563 2100 5600 2200 5700 564 Entry Wire Line 565 2100 5700 2200 5800 566 Entry Wire Line 567 2100 5800 2200 5900 568 Entry Wire Line 569 2100 5900 2200 6000 570 Entry Wire Line 571 2100 6000 2200 6100 572 Entry Wire Line 573 2100 6100 2200 6200 574 Wire Wire Line 575 2200 5500 2900 5500 576 Wire Wire Line 577 2200 5600 2900 5600 578 Wire Wire Line 579 2200 5700 2900 5700 580 Wire Wire Line 581 2200 5800 2900 5800 582 Wire Wire Line 583 2200 5900 2900 5900 584 Wire Wire Line 585 2200 6000 2900 6000 586 Wire Wire Line 587 2200 6100 2900 6100 588 Wire Wire Line 589 2200 6200 2900 6200 590 Text GLabel 2000 3600 0 50 Input ~ 0 591 CAPS_LOCK 592 Wire Wire Line 593 2200 5400 2900 5400 594 Text GLabel 1300 3700 0 50 Output ~ 0 595 ROM 596 Wire Wire Line 597 2000 3600 2900 3600 598 Wire Wire Line 599 2300 3700 1300 3700 600 Wire Wire Line 601 2000 6300 2900 6300 602 Wire Wire Line 603 2000 6500 2900 6500 604 Wire Wire Line 605 1700 6600 2900 6600 606 Wire Wire Line 607 1700 6400 2900 6400 608 $Sheet 609 S 4800 7800 700 300 610 U 61DB955D 611 F0 "Video" 50 612 F1 "video.sch" 50 613 $EndSheet 614 Wire Wire Line 615 6300 5500 6200 5500 616 Wire Wire Line 617 6300 5100 6200 5100 618 Wire Wire Line 619 5800 5100 5900 5100 620 Wire Wire Line 621 5800 5500 5900 5500 622 Wire Wire Line 623 5800 5300 5800 5100 624 Wire Wire Line 625 5800 5300 5800 5500 626 Connection ~ 5800 5300 627 Wire Wire Line 628 5600 5300 5800 5300 629 Text GLabel 6300 5500 2 50 Input ~ 0 630 0V 631 $Comp 632 L Device:C C9 633 U 1 1 621AE941 634 P 6050 5500 635 F 0 "C9" V 5798 5500 50 0000 C CNN 636 F 1 "1??F" V 5889 5500 50 0000 C CNN 637 F 2 "" H 6088 5350 50 0001 C CNN 638 F 3 "~" H 6050 5500 50 0001 C CNN 639 1 6050 5500 640 0 1 1 0 641 $EndComp 642 Text GLabel 6300 5100 2 50 Input ~ 0 643 5V 644 $Comp 645 L Device:R R7 646 U 1 1 61FA16A2 647 P 6050 5100 648 F 0 "R7" V 5843 5100 50 0000 C CNN 649 F 1 "56000R" V 5934 5100 50 0000 C CNN 650 F 2 "" V 5980 5100 50 0001 C CNN 651 F 3 "~" H 6050 5100 50 0001 C CNN 652 1 6050 5100 653 0 1 1 0 654 $EndComp 655 Text GLabel 7100 6100 2 50 Output ~ 0 656 ~CSYNC 657 Text GLabel 7100 6700 2 50 Output ~ 0 658 BLUE 659 Text GLabel 7100 7300 2 50 Output ~ 0 660 GREEN 661 Text GLabel 7100 7900 2 50 Output ~ 0 662 RED 663 Wire Wire Line 664 5600 5700 6100 5700 665 Text GLabel 4900 7000 2 50 Output ~ 0 666 ~HS 667 Wire Wire Line 668 4800 6750 4800 7000 669 Wire Wire Line 670 4800 7000 4900 7000 671 Text GLabel 5800 2300 2 50 BiDi ~ 0 672 CASSETTE_RC 673 Text GLabel 5800 2600 2 50 Output ~ 0 674 CASSETTE_MOTOR 675 Wire Wire Line 676 5600 2300 5800 2300 677 Wire Wire Line 678 5600 2600 5800 2600 679 $Sheet 680 S 4800 7200 700 300 681 U 62411C42 682 F0 "UHF" 50 683 F1 "UHF.sch" 50 684 $EndSheet 685 Wire Wire Line 686 5600 6300 5800 6300 687 Wire Wire Line 688 5600 5900 6000 5900 689 Text Notes 5800 9150 0 50 ~ 0 690 Issue 6 boards tend to have\nIC19 (74LS08) fitted for\nsome kind of buffering\nof the video signals.\n\nLK7 is supposedly connected\nto +5V to ensure this. 691 $Comp 692 L 74xx:74LS08 IC19 693 U 1 1 61E3E3E3 694 P 6700 7300 695 F 0 "IC19" H 6700 7625 50 0000 C CNN 696 F 1 "74LS08" H 6700 7534 50 0000 C CNN 697 F 2 "" H 6700 7300 50 0001 C CNN 698 F 3 "http://www.ti.com/lit/gpn/sn74LS08" H 6700 7300 50 0001 C CNN 699 1 6700 7300 700 1 0 0 -1 701 $EndComp 702 $Comp 703 L 74xx:74LS08 IC19 704 U 2 1 61E3E49E 705 P 6700 7900 706 F 0 "IC19" H 6700 8225 50 0000 C CNN 707 F 1 "74LS08" H 6700 8134 50 0000 C CNN 708 F 2 "" H 6700 7900 50 0001 C CNN 709 F 3 "http://www.ti.com/lit/gpn/sn74LS08" H 6700 7900 50 0001 C CNN 710 2 6700 7900 711 1 0 0 -1 712 $EndComp 713 $Comp 714 L 74xx:74LS08 IC19 715 U 3 1 61E3E509 716 P 6700 6100 717 F 0 "IC19" H 6700 6425 50 0000 C CNN 718 F 1 "74LS08" H 6700 6334 50 0000 C CNN 719 F 2 "" H 6700 6100 50 0001 C CNN 720 F 3 "http://www.ti.com/lit/gpn/sn74LS08" H 6700 6100 50 0001 C CNN 721 3 6700 6100 722 1 0 0 -1 723 $EndComp 724 $Comp 725 L 74xx:74LS08 IC19 726 U 4 1 61E3E573 727 P 6700 6700 728 F 0 "IC19" H 6700 7025 50 0000 C CNN 729 F 1 "74LS08" H 6700 6934 50 0000 C CNN 730 F 2 "" H 6700 6700 50 0001 C CNN 731 F 3 "http://www.ti.com/lit/gpn/sn74LS08" H 6700 6700 50 0001 C CNN 732 4 6700 6700 733 1 0 0 -1 734 $EndComp 735 $Comp 736 L 74xx:74LS08 IC19 737 U 5 1 61E3E5E4 738 P 7200 8900 739 F 0 "IC19" H 7430 8946 50 0000 L CNN 740 F 1 "74LS08" H 7430 8855 50 0000 L CNN 741 F 2 "" H 7200 8900 50 0001 C CNN 742 F 3 "http://www.ti.com/lit/gpn/sn74LS08" H 7200 8900 50 0001 C CNN 743 5 7200 8900 744 1 0 0 -1 745 $EndComp 746 Wire Wire Line 747 5800 6300 5800 7800 748 Wire Wire Line 749 5800 7800 6400 7800 750 Wire Wire Line 751 5900 6100 5900 7200 752 Wire Wire Line 753 5900 7200 6400 7200 754 Wire Wire Line 755 5600 6100 5900 6100 756 Wire Wire Line 757 6000 5900 6000 6800 758 Wire Wire Line 759 6000 6800 6400 6800 760 Wire Wire Line 761 6100 5700 6100 6200 762 Wire Wire Line 763 6100 6200 6400 6200 764 $Comp 765 L Jumper:Jumper_2_Bridged LK7 766 U 1 1 61EC346B 767 P 6600 8400 768 F 0 "LK7" H 6600 8595 50 0000 C CNN 769 F 1 "Jumper_2_Bridged" H 6600 8504 50 0000 C CNN 770 F 2 "" H 6600 8400 50 0001 C CNN 771 F 3 "~" H 6600 8400 50 0001 C CNN 772 1 6600 8400 773 1 0 0 -1 774 $EndComp 775 Wire Wire Line 776 6400 8000 6200 8000 777 Wire Wire Line 778 6200 8000 6200 8400 779 Wire Wire Line 780 6200 8400 6400 8400 781 Wire Wire Line 782 6200 8000 6200 7400 783 Wire Wire Line 784 6200 7400 6400 7400 785 Connection ~ 6200 8000 786 Wire Wire Line 787 6200 7400 6200 6600 788 Wire Wire Line 789 6200 6600 6400 6600 790 Connection ~ 6200 7400 791 Wire Wire Line 792 6200 6600 6200 6000 793 Wire Wire Line 794 6200 6000 6400 6000 795 Connection ~ 6200 6600 796 Wire Wire Line 797 7000 6100 7100 6100 798 Wire Wire Line 799 7000 6700 7100 6700 800 Wire Wire Line 801 7000 7300 7100 7300 802 Wire Wire Line 803 7000 7900 7100 7900 804 Text GLabel 6900 8400 2 50 Input ~ 0 805 5V 806 Wire Wire Line 807 6900 8400 6800 8400 808 Text GLabel 7200 8300 1 50 Input ~ 0 809 5V 810 Wire Wire Line 811 7200 8300 7200 8400 812 Text GLabel 7200 9500 3 50 Input ~ 0 813 0V 814 Wire Wire Line 815 7200 9500 7200 9400 816 Text GLabel 6100 8400 0 50 Output ~ 0 817 BUFFER_ENABLE 818 Wire Wire Line 819 6100 8400 6200 8400 820 Connection ~ 6200 8400 821 Wire Bus Line 822 2100 1600 2100 1900 823 Wire Bus Line 824 2100 3100 2100 3400 825 Wire Bus Line 826 2100 2000 2100 3000 827 Wire Bus Line 828 2100 5400 2100 6100 829 Wire Bus Line 830 2100 3800 2100 5300 831 Text Notes 1400 10500 0 50 ~ 0 832 PL4 introduced for the two separate connections\non the original board. 833 $EndSCHEMATC