Electronic Arrays 9002
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General information | |
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Launched | 1976 |
Discontinued | 1977 |
Common manufacturer | |
Performance | |
Max. CPU clock rate | 4 MHz |
Data width | 8 |
Address width | 12 |
Architecture and classification | |
Instruction set | Electronic Arrays 9002 |
Number of instructions | 55 |
Physical specifications | |
Package |
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The Electronic Arrays 9002, or EA9002, was an
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
Electronic Arrays (EA) had problems with the new depletion-load NMOS logic 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 NEC the next year.
History
Electronic Arrays had their first major success in 1970 with a six-chip
At the time the 9002 was designed, the
In the mid-1970s,
Another major change taking place in the mid-1970s was the introduction of
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
Unfortunately for Electronic Arrays, ramping up the depletion-load fabrication line did not go as well as it did for companies like MOS Technology, and by the end of 1976 they were still struggling with yields.[10][11] By the next year, chips like the 6502 and Z80 were hitting their production stride and the EA9002 still had no significant design wins.[12] The company eventually gave up and cancelled the line in November 1977.[12] Financially troubled,[13] Electronic Arrays was purchased by NEC the next year and later merged into NEC Electronics USA, along with two other of NEC's subsidiaries, in 1981.[14]
One electronics company, the Pro-Log Corporation of
Description
Programming model
The 9002 had 55 instructions,
There were only a small number of two-byte instructions, typically for specifying an address or using an immediate value. For instance, LAI (opcode 0D) would load an immediate value into the accumulator, and was followed by a second byte with the 8-bit immediate value. LRI 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 IRJ and DRJ, which incremented or decremented a selected register and then jumped if it was non-zero. The second byte specified the jump location.[17]
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:[19]
LAI 08 ; LAI=load-acc-immediate - copy the page number, 8, into the accumulator
CAP 4 ; CAP=copy-acc-to-page-register - store that 8 in the page part of register 4
LRI 4, 00 ; LRI=load-reg-immediate - load the value 0 into the lower part of register 4
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 INPut or OUTput and specifying register 4 in the LSBs.[17]
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 RDS and WRS. One curious feature is that the scratchpad could also be used directly as an operand in addition and subtraction operations, using the ADS and SUS operations, thereby avoiding having to load the value to the accumulator, save it to a register, and then add.[19]
The
Other notes
The 9002 normally ran at 4 MHz. It was reported to have a 2 microsecond instruction fetch and execution time,[20][21] although another source says 3.2 microseconds for single byte instructions and 6.4 microseconds for two byte instructions.[15]
Support systems
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.[22] The only driver IC they introduced was the EA2000 99-key keyboard controller.[23]
Development was carried out with a
Notes
References
Citations
- ^ a b Wickes 1976, p. 36.
- ^ "U. S. fires first shot at Japanese calculator lead" (PDF). Electronics. 44 (4). McGraw-Hill: 37–38. February 15, 1971.
- ^ a b Cushman 1975.
- ^ Weissberger, Alan; Jack Irwin; Soo Nam Kim (July 8, 1976). "Processor family specializes in dedicated control" (PDF). Electronics. 49 (14). McGraw-Hill: 84–89.
- ^ Bagnall, Brian. Commodore. Variant Press.
The 6507, which was a subset of [the 6502], could be made at a cheaper price. It was designed to be a really small package.
- ^
Jerry C. Whitaker (2005). Microelectronics (2nd ed.). CRC Press. p. 6-7–6-10. ISBN 978-0-8493-3391-0.
- ^ Wickes 1976, p. 41.
- ^ Wickes 1976, p. 42.
- ^ Wickes 1976, p. 46.
- ^ "Electronic Arrays". Microelectronics Newsletter. Integrated Circuit Engineering Corporation. September 18, 1976. p. 1. Retrieved June 12, 2018 – via Smithsonian Institution.
- ^ Hoefler, Don C. (September 18, 1976). "Setbacks". Microelectronics News with Manager's Casebook. p. 4 – via Smithsonian Institution.
- ^ a b Cushman, Robert (November 20, 1977). "EDN's Fourth Annual Microprocessor Directory" (PDF). EDN. p. 45. Retrieved June 23, 2018.
EA9002—The project staff at Electronic Arrays associated with this μP 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 effort.
- ISBN 9781501723919.
- ^ "Nippon Merges U.S. Arms, Forms NEC Electronics". Computerworld. Vol. 15, no. 16. April 20, 1981. p. 78.
- ^ a b "PRO-LOG ANNOUNCES 9002 CARD" (PDF). Microcomputer Digest. Vol. 3, no. 7. January 1977. p. 11. Archived from the original (PDF) on July 25, 2020. Retrieved June 12, 2018.
- ^ Osborne 1978, p. xliii.
- ^ a b c d e Wickes 1976, p. 48.
- ISBN 978-0-08-057712-8.
- ^ a b Wickes 1976, p. 52.
- ^ Savon, Karl (May 1976). "State of Solid State" (PDF). Radio-Electronics: 69.
- ^ "New low-end 8-bit microprocessor" (PDF). Microcomputer Digest. Vol. 2, no. 6. December 1975. pp. 1, 4. Archived from the original (PDF) on March 24, 2020. Retrieved June 12, 2018.
- ^ McCoy 1976, p. 66.
- ^ a b Wickes 1976, p. 54.
- S2CID 14427753.
Bibliography
- McCoy, Michael (January 22, 1976). A Microprocessor Designed with the User in Mind (PDF). Microprocessor/Memory Proceedings Integrated Circuit Applications Conference. Electronic Engineering Times. pp. 36–54.
- Wickes, William (January 22, 1976). Introducing the 32k Read Only Memory (PDF). Microprocessor/Memory Proceedings Integrated Circuit Applications Conference. Electronic Engineering Times. pp. 55–67.
- Osborne, Adam (1978). An Introduction to Microcomputers: Voume II, Some Real Products (PDF).
- Cushman, Robert H. (September 20, 1975). "2-1/2 Generation μP's – $10 Parts That Perform Like Low-End Mini's" (PDF). EDN. 20 (17). Cahners Publishing: 36–42. Archived from the original (PDF) on April 24, 2016. Retrieved June 12, 2018.