29:
295:. For embedded controllers, this could represent a significant cost, so it was desirable for designers to add a small amount of "scratchpad RAM" to the system to avoid having to add additional RAM chips to the board. As most systems would have little or no external RAM and small programs in ROM, it was also common to use smaller
555:
As the system was not developed for very long before it was cancelled, few support chips were available. EA did have a line of ROMs and static RAM, and around the same time they introduced a new 32x1 (4 kB) ROM which was often illustrated being used with the 9002. The only driver IC they introduced
214:
to 4,096 bytes. This was not a significant limitation at the time, as memory was still very expensive and the target market could often make do with the internal RAM. There was a single 8-bit accumulator used for arithmetic and eight 8-bit registers it could use for storing temporary values. These
280:(RAM) needed was very small – keeping track of the number of gallons pumped and the total cost for instance. This led designers to develop systems that included as many of these features as possible on a single chip so that the total number of chips in a complete system was reduced.
451:
Addressing was normally accomplished in two steps, one to load the lower 8-bits of the address into one of the "general purpose" registers, and then a second to load the most significant 4-bits of the address into the "page register". The introductory material uses this example:
546:
The 9002 normally ran at 4 MHz. It was reported to have a 2 microsecond instruction fetch and execution time, although another source says 3.2 microseconds for single byte instructions and 6.4 microseconds for two byte instructions.
392:, in that it had the scratchpad memory and overall concept of the F8 with the multiple general purpose registers of the COSMAC. However, by the time the second edition was published in 1977, the chapters covering the EA9002 and
310:
design. Previous fabrication systems using "enhancement-load" circuits required three input voltages, one of which was typically +12V. This not only made the circuit layout more complex and often required a more complex
850:
EA9002—The project staff at
Electronic Arrays associated with this ÎĽP has been disbanded and the marketing effort closed down. The firm entered the market too late and was too small to mount a competitive sales
413:. Most of these were a one-address format, in which case the instruction opcode was normally split in two, with four bits specifying the operation and the other four a register. For instance, the
503:
Separate instructions were also needed to read and write the internal scratch RAM, which otherwise operated like external memory and had to be loaded and saved through the accumulator using
440:
did the same for the other registers, with the LSBs indicating which register to use. Jumps and branches also used the two-byte format, supplying the address offset within a "page". So did
357:, and by the end of 1976 they were still struggling with yields. By the next year, chips like the 6502 and Z80 were hitting their production stride and the EA9002 still had no significant
326:
The 9002 was designed to take advantage of all of these emerging concepts. It included 64 bytes of scratchpad RAM and a 12-bit address space, allowing it to be packaged in a 28-pin
245:
chipset, which they had steadily improved over several steps into a single-chip format. However, other companies had continually beat them to market with reduced chip counts, first
229:
fabrication line and struggled with deliveries. By 1977, the 6502 and Z80 had taken over much of the market, and in
November EA stopped selling the design. The company was sold to
346:
calls did not have to use the scratchpad. This allowed a simple controller to be implemented in two chips, the 9002 and a ROM, along with any required interface hardware like an
571:. A system emulator was part of the package, and a simple start-up board was also available. ASM/GEN and SIM/GEN, systems for developing for cross-assemblers and simulators in
913:
1253:
1054:
253:, and later a number of Japanese electronics firms. By the mid-1970s the company desperately needed a new product line and began development of a CPU.
183:
microprocessor released in 1976. It was designed to be easy to implement in systems with few required support chips. It included 64 bytes of built-in
1210:
999:
727:
511:. One curious feature is that the scratchpad could also be used directly as an operand in addition and subtraction operations, using the
1031:
448:, which incremented or decremented a selected register and then jumped if it was non-zero. The second byte specified the jump location.
428:
There were only a small number of two-byte instructions, typically for specifying an address or using an immediate value. For instance,
210:
The 28-pin design did not have enough pins left over to implement a 16-bit address bus, and instead had 12 address lines which limited
874:
361:. The company eventually gave up and cancelled the line in November 1977. Financially troubled, Electronic Arrays was purchased by
353:
Unfortunately for
Electronic Arrays, ramping up the depletion-load fabrication line did not go as well as it did for companies like
421:(MSB) "06", and the four least significant bits (LSB) specified which of the registers to add to the accumulator, 0 through 7. The
828:
492:
This sets the address in register 4 to the first location in page 8. Data could then be loaded or saved to the accumulator using
1179:
1165:
188:
1258:
1187:. Microprocessor/Memory Proceedings Integrated Circuit Applications Conference. Electronic Engineering Times. pp. 55–67.
1173:. Microprocessor/Memory Proceedings Integrated Circuit Applications Conference. Electronic Engineering Times. pp. 36–54.
1065:
924:
436:) would load an immediate value into the accumulator, and was followed by a second byte with the 8-bit immediate value.
130:
673:
632:
319:(TTL) which ran at +5V. Interfacing older chips with the wide variety of TTL components generally required additional
316:
1117:
Johnson, G.R.; Mueller, R.A. (January 1977). "Automated
Generation of Cross-System Software for Microcomputers".
704:
The 6507, which was a subset of , could be made at a cheaper price. It was designed to be a really small package.
307:
226:
519:
operations, thereby avoiding having to load the value to the accumulator, save it to a register, and then add.
315:
as well, it also made it more difficult to interface with external support circuits which were mostly based on
365:
the next year and later merged into NEC Electronics USA, along with two other of NEC's subsidiaries, in 1981.
260:
had not yet emerged as a major market and processors of the era were mostly used in embedded electronics like
320:
96:
323:, but the new depletion-load designs worked at +5V and interfaced directly, reducing cost and complexity.
1225:
523:
373:
261:
242:
527:
418:
369:
327:
277:
216:
192:
184:
160:
393:
1193:
1142:
890:
219:
of the 8-bit registers, extending them to 12-bits for indexing and similar address manipulation.
717:
358:
347:
1206:
1134:
1039:
995:
983:
870:
723:
250:
222:
80:
779:
1126:
806:
273:
269:
560:
204:
836:
564:
354:
28:
1247:
895:
300:
296:
265:
257:
1146:
195:
which made it less expensive to implement than contemporary designs like the 40-pin
591:
Although the company did use the term "controller" prominently in its descriptions.
568:
425:
also used the four MSB as "06", but the four LSBs were 8 thorough F (hexidecimal).
385:
381:
312:
864:
288:
284:
211:
572:
410:
389:
343:
339:
292:
99:
1138:
487:; LRI=load-reg-immediate - load the value 0 into the lower part of register 4
472:; CAP=copy-acc-to-page-register - store that 8 in the page part of register 4
396:
were removed as the former had been cancelled and the latter never released.
1130:
530:(BCD) arithmetic, as was common for the era. This option was turned on with
331:
330:(DIP), compared to the 40-pin packaging of most designs of the era like the
200:
786:. Integrated Circuit Engineering Corporation. September 18, 1976. p. 1
306:
Another major change taking place in the mid-1970s was the introduction of
1211:"2-1/2 Generation μP's – $ 10 Parts That Perform Like Low-End Mini's"
335:
196:
463:; LAI=load-acc-immediate - copy the page number, 8, into the accumulator
241:
Electronic Arrays had their first major success in 1970 with a six-chip
1064:. Vol. 2, no. 6. December 1975. pp. 1, 4. Archived from
384:
devoted a chapter to the 9002. He described it as a combination of the
246:
923:. Vol. 3, no. 7. January 1977. p. 11. Archived from
299:
as this allowed the number of pins to be reduced, which simplified
215:
were supported by another eight 4-bit registers which acted as the
180:
1195:
An
Introduction to Microcomputers: Voume II, Some Real Products
362:
230:
672:
Weissberger, Alan; Jack Irwin; Soo Nam Kim (July 8, 1976).
899:. Vol. 15, no. 16. April 20, 1981. p. 78.
1100:
1098:
1013:
1011:
965:
963:
961:
959:
957:
615:
613:
655:
653:
633:"U. S. fires first shot at Japanese calculator lead"
368:
268:, gas pumps, and similar roles. For these uses, the
674:"Processor family specializes in dedicated control"
152:
147:
139:
129:
124:
116:
108:
94:
89:
73:
58:
40:
35:
891:"Nippon Merges U.S. Arms, Forms NEC Electronics"
813:. p. 4 – via Smithsonian Institution.
291:, and most systems used the much more expensive
207:, although that term did not exist at the time.
1224:(17). Cahners Publishing: 36–42. Archived from
1167:A Microprocessor Designed with the User in Mind
409:The 9002 had 55 instructions, patterned on the
829:"EDN's Fourth Annual Microprocessor Directory"
811:Microelectronics News with Manager's Casebook
722:(2nd ed.). CRC Press. p. 6-7–6-10.
8:
988:Advances in Electronics and Electron Physics
21:
646:(4). McGraw-Hill: 37–38. February 15, 1971.
556:was the EA2000 99-key keyboard controller.
500:put and specifying register 4 in the LSBs.
287:had not yet emerged as the primary form of
984:"Microprocessors and their use in Physics"
338:. It also included a separate seven-level
27:
908:
906:
869:. Cornell University Press. p. 126.
982:Davies, Anthony J. (January 31, 1979).
948:
659:
609:
584:
526:(ALU) supported both binary and packed
376:in early 1977. In the first edition of
256:At the time the 9002 was designed, the
1254:Computer-related introductions in 1976
1104:
1017:
969:
822:
820:
805:Hoefler, Don C. (September 18, 1976).
766:
754:
742:
619:
20:
1089:
827:Cushman, Robert (November 20, 1977).
567:which was also available online with
191:devices. It was packaged in a 28-pin
7:
1181:Introducing the 32k Read Only Memory
1178:Wickes, William (January 22, 1976).
794:– via Smithsonian Institution.
575:, supported the EA9002 as a target.
1164:McCoy, Michael (January 22, 1976).
559:Development was carried out with a
187:and could be directly connected to
1055:"New low-end 8-bit microprocessor"
14:
378:An Introduction to Microcomputers
863:Encarnation, Dennis J. (2018).
225:(EA) had problems with the new
203:. Today it would be known as a
125:Architecture and classification
1:
914:"PRO-LOG ANNOUNCES 9002 CARD"
784:Microelectronics Newsletter
317:transistor-transistor logic
46:; 48 years ago
1275:
716:Jerry C. Whitaker (2005).
350:or even just a flip-flop.
687:(14). McGraw-Hill: 84–89.
308:depletion-load NMOS logic
227:depletion-load NMOS logic
26:
1030:Savon, Karl (May 1976).
454:
276:(ROM) and the amount of
1131:10.1109/c-m.1977.217493
994:. Academic Press: 113.
342:of 12-bit addresses so
272:was normally stored on
148:Physical specifications
1209:(September 20, 1975).
1192:Osborne, Adam (1978).
1032:"State of Solid State"
262:electronic calculators
173:Electronic Arrays 9002
140:Number of instructions
135:Electronic Arrays 9002
22:Electronic Arrays 9002
1259:8-bit microprocessors
524:arithmetic logic unit
419:most significant bits
374:single-board computer
372:, used the 9002 in a
243:electronic calculator
217:most significant bits
1062:Microcomputer Digest
921:Microcomputer Digest
528:binary coded decimal
417:instruction had the
370:Monterey, California
328:dual in-line package
278:random-access memory
131:Instruction set
866:Rivals Beyond Trade
780:"Electronic Arrays"
74:Common manufacturer
36:General information
23:
16:1976 microprocessor
1207:Cushman, Robert H.
283:In the mid-1970s,
1231:on April 24, 2016
1071:on March 24, 2020
1040:Radio-Electronics
1001:978-0-08-057712-8
729:978-0-8493-3391-0
702:. Variant Press.
405:Programming model
251:Texas Instruments
223:Electronic Arrays
169:
168:
81:Electronic Arrays
1266:
1240:
1238:
1236:
1230:
1215:
1202:
1200:
1188:
1186:
1174:
1172:
1151:
1150:
1114:
1108:
1102:
1093:
1087:
1081:
1080:
1078:
1076:
1070:
1059:
1051:
1045:
1044:
1036:
1027:
1021:
1015:
1006:
1005:
979:
973:
967:
952:
951:, p. xliii.
946:
940:
939:
937:
935:
930:on July 25, 2020
929:
918:
910:
901:
900:
887:
881:
880:
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853:
847:
845:
833:
824:
815:
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802:
796:
795:
793:
791:
776:
770:
764:
758:
752:
746:
740:
734:
733:
719:Microelectronics
713:
707:
706:
698:Bagnall, Brian.
695:
689:
688:
678:
669:
663:
657:
648:
647:
637:
629:
623:
617:
592:
589:
537:
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518:
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479:
476:
473:
470:
467:
464:
461:
458:
447:
443:
439:
435:
431:
424:
416:
274:read-only memory
270:computer program
69:
67:
54:
52:
47:
31:
24:
1274:
1273:
1269:
1268:
1267:
1265:
1264:
1263:
1244:
1243:
1234:
1232:
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1213:
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1191:
1184:
1177:
1170:
1163:
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1155:
1154:
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1111:
1103:
1096:
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1024:
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1002:
981:
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968:
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931:
927:
916:
912:
911:
904:
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831:
826:
825:
818:
804:
803:
799:
789:
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778:
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765:
761:
753:
749:
741:
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730:
715:
714:
710:
697:
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676:
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666:
658:
651:
635:
631:
630:
626:
618:
611:
606:
601:
596:
595:
590:
586:
581:
563:running on the
561:macro assembler
553:
551:Support systems
544:
535:
531:
516:
512:
508:
504:
497:
493:
490:
489:
486:
483:
480:
477:
474:
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468:
465:
462:
459:
456:
445:
441:
437:
433:
429:
422:
414:
407:
402:
239:
233:the next year.
205:microcontroller
165:
85:
65:
63:
50:
48:
45:
17:
12:
11:
5:
1272:
1270:
1262:
1261:
1256:
1246:
1245:
1242:
1241:
1203:
1189:
1175:
1159:
1156:
1153:
1152:
1109:
1094:
1082:
1046:
1022:
1007:
1000:
974:
953:
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902:
882:
875:
855:
816:
797:
771:
759:
747:
735:
728:
708:
690:
664:
649:
624:
608:
607:
605:
602:
600:
597:
594:
593:
583:
582:
580:
577:
565:IBM System/360
552:
549:
543:
540:
455:
406:
403:
401:
398:
394:Rockwell PPS-8
355:MOS Technology
297:address spaces
266:cash registers
238:
235:
167:
166:
164:
163:
156:
154:
150:
149:
145:
144:
141:
137:
136:
133:
127:
126:
122:
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118:
114:
113:
110:
106:
105:
102:
92:
91:
87:
86:
84:
83:
77:
75:
71:
70:
60:
56:
55:
42:
38:
37:
33:
32:
15:
13:
10:
9:
6:
4:
3:
2:
1271:
1260:
1257:
1255:
1252:
1251:
1249:
1227:
1223:
1219:
1212:
1208:
1204:
1197:
1196:
1190:
1183:
1182:
1176:
1169:
1168:
1162:
1161:
1157:
1148:
1144:
1140:
1136:
1132:
1128:
1124:
1120:
1113:
1110:
1107:, p. 54.
1106:
1101:
1099:
1095:
1092:, p. 66.
1091:
1086:
1083:
1067:
1063:
1056:
1050:
1047:
1042:
1041:
1033:
1026:
1023:
1020:, p. 52.
1019:
1014:
1012:
1008:
1003:
997:
993:
989:
985:
978:
975:
972:, p. 48.
971:
966:
964:
962:
960:
958:
954:
950:
945:
942:
926:
922:
915:
909:
907:
903:
898:
897:
896:Computerworld
892:
886:
883:
878:
876:9781501723919
872:
868:
867:
859:
856:
852:
839:
838:
830:
823:
821:
817:
812:
808:
801:
798:
785:
781:
775:
772:
769:, p. 46.
768:
763:
760:
757:, p. 42.
756:
751:
748:
745:, p. 41.
744:
739:
736:
731:
725:
721:
720:
712:
709:
705:
701:
694:
691:
686:
682:
675:
668:
665:
661:
656:
654:
650:
645:
641:
634:
628:
625:
622:, p. 36.
621:
616:
614:
610:
603:
598:
588:
585:
578:
576:
574:
570:
566:
562:
557:
550:
548:
541:
539:
534:and off with
529:
525:
520:
501:
453:
449:
426:
420:
412:
404:
399:
397:
395:
391:
387:
383:
379:
375:
371:
366:
364:
360:
356:
351:
349:
345:
341:
337:
333:
329:
324:
322:
318:
314:
309:
304:
302:
301:circuit board
298:
294:
290:
286:
281:
279:
275:
271:
267:
263:
259:
258:microcomputer
254:
252:
248:
244:
236:
234:
232:
228:
224:
220:
218:
213:
208:
206:
202:
198:
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182:
178:
174:
162:
158:
157:
155:
151:
146:
142:
138:
134:
132:
128:
123:
119:
117:Address width
115:
111:
107:
103:
101:
98:
93:
88:
82:
79:
78:
76:
72:
61:
57:
43:
39:
34:
30:
25:
19:
1233:. Retrieved
1226:the original
1221:
1217:
1194:
1180:
1166:
1158:Bibliography
1125:(1): 23–31.
1122:
1118:
1112:
1085:
1073:. Retrieved
1066:the original
1061:
1049:
1038:
1025:
991:
987:
977:
949:Osborne 1978
944:
932:. Retrieved
925:the original
920:
894:
885:
865:
858:
849:
842:. Retrieved
840:. p. 45
835:
810:
800:
788:. Retrieved
783:
774:
762:
750:
738:
718:
711:
703:
699:
693:
684:
680:
667:
660:Cushman 1975
643:
639:
627:
587:
569:National CSS
558:
554:
545:
521:
502:
491:
450:
427:
408:
386:Fairchild F8
382:Adam Osborne
377:
367:
352:
325:
313:power supply
305:
282:
255:
240:
221:
209:
176:
172:
170:
59:Discontinued
18:
1105:Wickes 1976
1018:Wickes 1976
970:Wickes 1976
767:Wickes 1976
755:Wickes 1976
743:Wickes 1976
681:Electronics
640:Electronics
620:Wickes 1976
542:Other notes
400:Description
359:design wins
289:main memory
285:dynamic RAM
212:main memory
90:Performance
1248:Categories
1090:McCoy 1976
807:"Setbacks"
599:References
573:FORTRAN IV
411:Intel 4040
390:RCA COSMAC
348:Intel 8212
344:subroutine
340:call stack
293:static RAM
109:Data width
104:4 MHz
100:clock rate
1139:0018-9162
700:Commodore
604:Citations
332:Zilog Z80
201:Zilog Z80
179:, was an
1235:June 12,
1147:14427753
1119:Computer
1075:June 12,
934:June 12,
844:June 23,
790:June 12,
432:(opcode
336:MOS 6502
303:layout.
197:MOS 6502
41:Launched
851:effort.
321:latches
237:History
159:28 pin
153:Package
64: (
49: (
1145:
1137:
998:
873:
726:
496:ut or
247:Mostek
177:EA9002
1229:(PDF)
1214:(PDF)
1199:(PDF)
1185:(PDF)
1171:(PDF)
1143:S2CID
1069:(PDF)
1058:(PDF)
1043:: 69.
1035:(PDF)
928:(PDF)
917:(PDF)
832:(PDF)
677:(PDF)
636:(PDF)
579:Notes
181:8-bit
175:, or
95:Max.
1237:2018
1135:ISSN
1077:2018
996:ISBN
936:2018
871:ISBN
846:2018
792:2018
724:ISBN
522:The
515:and
507:and
444:and
388:and
249:and
199:and
171:The
66:1977
62:1977
51:1976
44:1976
1218:EDN
1127:doi
837:EDN
536:SEB
532:SED
517:SUS
513:ADS
509:WRS
505:RDS
498:OUT
494:INP
475:LRI
466:CAP
457:LAI
446:DRJ
442:IRJ
438:LRI
430:LAI
423:SUB
415:ADD
363:NEC
334:or
231:NEC
193:DIP
189:TTL
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