78K

78K is the trademark name of 16- and 8-bit microcontroller family^{[1]: 23-4–23-5 [2]: 78} manufactured by Renesas Electronics, originally developed by NEC^{[3][4]: 229} started in 1986.^{[5]: 7, line 2} The basis of 78K Family is an accumulator-based register-bank CISC architecture. 78K is a single-chip microcontroller, which usually integrates; program ROM, data RAM, serial interfaces, timers, I/O ports, an A/D converter, an interrupt controller, and a CPU core, on one die.^{[6][7]: 412}

78K Family microcontrollers

General information
Launched	1986; 37 years ago (1986)
Discontinued	current
Common manufacturer(s)	Renesas Electronics (formerly NEC)
Performance
Max. CPU clock rate	32 kHz to 24 MHz
Data width	16/8
Address width	20(24)/16
Architecture and classification
Application	Embedded
Instruction set	78K Family
Physical specifications
Cores	1
Products, models, variants
Variant(s)	78K0R, 78K0S, 78K0, 78K4, 78K6, 78K3, 78K7, 78K1, 78K2
History
Predecessor	87AD Family, 17K Family
Successor	RL78 Family

78K0/KX1+ board with in-circuit emulator; MINICUBE

78K0S/KA1+ Do It board

78K0R/KG3 Cool It board with in-circuit emulator; IECUBE ^{(formerly, MINICUBE2)}

Its application area is mainly simple mechanical system controls and man-machine interfaces.^[8][9][10]

Regarding software development tools, C compilers and macro-assemblers are available.^[11]: 99 As for development tool hardware, full probing-pod type and debug port type in-circuit emulators,^[12][13] and flash ROM programmers^{[14]: 22–24} are available.

Historically, the family has 11 series with 9 instruction set architectures. As of 2018, 3 instruction set architectures, those are 8-bit 78K0, 8-bit 78K0S, and 16-/8-bit 78K0R, are still promoted for customers' new designs.^[14] But in most of cases, migration to RL78 Family,^[15] which is a successor of 78K0R and almost binary level compatible with 78K0R,^[16]: 20 is recommended.^[17]

Variants

78K0 Series

78K0 Series [de] (also known as 78K/0) is a long-running 8-bit single chip microcontroller,^[18] which is the basis of 78K0S and 78K0R Series. It contains 8× 8-bit registers ×4 banks. For 16-bit calculating instructions, it performs ALU operation twice. Each instructions are performed serially without instruction pipelining. It has 16-bit 64K Byte address space.^[19] Some variants of 78K0 have affordable and compact type 8-bit R-2R D/A converter, which does not have monotonicity because it is not trimmed for adjustment nor followed by operational amplifier.

In its earlier stage, the Program Memory was one-time PROM (OTP), UV-EPROM, or mask ROM.^[20] But with the times, it became flash memory.^[21][22]

78K0S Series

78K0S Series (also known as 78K/0S) is a low-end version of 78K0.^[23][24][25] It has 8× 8-bit registers, but without any banks. In addition, some instructions, such as multiplication and division, are removed from 78K0 instruction set architecture.^[26]

78K0R Series

78K0R Series is a 16-bit single-chip microcontroller with 3-stage instruction pipelining.^[27] Its instruction set is similar to 78K0 and covers 16- and 8-bit operations. It has 20-bit 1M Byte address space.^[28] 75 instructions out of 80 are identical with that of RL78 Family; its successor.^{[16]: 20 [15][29]}

178K0 Series

178K0 Series (also known as 178K/0) is a successor of NEC's 17K Family 4-bit microcontroller for DTS (Digital Tuning Systems) and remote controls.^[30] It integrates 17K family's peripheral functions with the 78K0 8-bit CPU core on a chip.^[31]

178K0S Series

178K0S Series (also known as 178K/0S) is also a successor of 17K Family with the 78K0S CPU core.^[32]

78K4 Series

78K4 Series (also known as 78K/4) is a 16-bit single-chip microcontroller with 16 and 8-bit operations.^{[33][34][35][36]} It has 16× 8-bit registers ×4 banks, which can be also used for 8× 16-bit registers ×4 banks. Some of these registers can be also used as 24-bit extension for addressing modes.^[37] It has 24-bit 16M Byte address space. It has microcode-based operations named Macro Service with interrupt functions.^{[38]: §23.8, 560–593}

78K7 Series

78K7 Series (also known as 78K/7) is a 32-bit single-chip microcontroller with 32, 16 and 8 bit operations. It has 8× 32-bit registers ×16 banks, which can be also used for 16× 16-bit registers ×16 banks and 16× 8-bit registers ×16 banks. It has microcode-based operations named Macro Service with interrupt functions. It has 24-bit 16M Byte linear address space. It is used for some Quantum Fireball products,^{[39]: Photo 2} but shortly replaced with V850 Family 32-bit RISC microcontrollers.

78K6 Series

78K6 Series (also known as 78K/6) is a 16-bit single-chip microcontroller. Its life-time was short, and less variants.

78K1 Series

78K1 Series (also known as 78K/1) is an 8-bit single-chip microcontroller. It has 8× 8-bit registers ×4 banks. 78K1 series is targeted for servo controls of videocassette recorders. μPD78148 sub-series integrates 2 operational amplifiers.^[40]

78K3 Series

78K3 Series (also known as 78K/3) is a 16-bit single-chip microcontroller with 16 and 8 bit operations. It has 16× 8-bit ×8 banks, which can be also used for 8× 16-bit registers ×8 banks. Its address space is 16-bit 64K Byte. It is developed as high-end series of 78K Family. It has microcode-based operations named Macro Service with interrupt functions.^{[41]: §13.4, 261–280}

This series is used for hard disk drives, especially Quantum Fireball Series.^[42] μPD78364 sub-series is used for inverter compressor controls.^[43] It is also used for traction control systems of some cars.

78K2 Series

78K2 Series (also known as 78K/2) is an 8-bit single-chip microcontroller. It has 8× 8-bit registers ×4 banks. It is developed as general purpose series of 78K Family.^[44]

Predecessors

87AD Family

87AD Family^[4]: 229 is an 8-bit single-chip microcontroller. It has 8× 8-bit registers ×4 banks. Its instruction set architecture became the basis of 78K.^[45]

17K Family

17K Family^[4]: 229 is a 4-bit single-chip microcontroller, especially dedicated for DTS (Digital Tuning Systems) and remote controls. It has 2 plane of 128× 4-bit register files, and sophisticated fully orthogonal instruction set. This instruction set is completely different from that of 78K Family.^[30]

Table list of 78K Family

Series	ALU	Registers	Instructions	Pipeline	Remark	Documents
RL78-S3	16-bit	8× 8-bit ×4 banks	81 (75+6)	3-stage	Successor of 78K0R	^[29]^: 8
RL78-S2	16-bit	8× 8-bit ×4 banks	75	3-stage
RL78-S1	8-bit	8× 8-bit (no bank)	74 (75-1)	3-stage
78K0R	16-bit	8× 8-bit ×4 banks	80 (75+5)	3-stage	Extended 78K/0	^[28]^: 18
78K0S	8-bit	8× 8-bit (no bank)	47	none	Simplified 78K/0	^[25]
78K0	8-bit	8× 8-bit ×4 banks	48	none	Basic 78K/0 core	^[19]
178K0S	8-bit	8× 8-bit	47	none	78K/0S for DTS; ^Digital Tuning System	^[25]^[32]
178K0	8-bit	8× 8-bit ×4 banks	48	none	78K/0 for DTS	^[19]^[31]
78K4	16-bit	16× 8-bit ×4 banks	113	none	Macro service available	^[37]^: 24, 128
78K7	32-bit	16× 16-bit ×16 banks		none	Macro service available	^[46]
78K6	16-bit				Macro service available
78K1	8-bit	8× 8-bit ×4 banks	64	none	For VCR servo controls	^[40]^: 3, 39
78K3	16-bit	16× 8-bit ×8 banks	113–115	none	Macro service available	^[47]^: 3–28, 45
78K2	8-bit	8× 8-bit ×4 banks	65	none	General purpose	^[44]^: 16, 50
87AD	8-bit	8× 8-bit ×2 banks	CMOS: 159 NMOS: 158	none	Predecessor of 78K	^[45]^: 21, 39
(17K)	4-bit	128× 4-bit ×2 banks	47	none	Predecessor of 178K	^[30]

See also

• RL78
• V850
• Renesas 740
• IEBus

References

1. Oklobdzija, Vojin G. (2001). The Computer Engineering Handbook. CRC Press. ISBN 9780849308857.
2. Edwards, Lewin A. R. W. (2006). So, You Wanna be an Embedded Engineer: The Guide to Embedded Engineering, from Consultancy to the Corporate Ladder. Newnes. p. 78. ISBN 9780750679534. NEC 78K.
3. "78k | The CPU Shack Museum". www.cpushack.com.
4. Parai, Manas Kumar; Das, Banasree; Das, Gautam (January 2013). "An Overview of Microcontroller Unit: From Proper Selection to Specific Application". International Journal of Soft Computing and Engineering (IJSCE). 2 (6): 228–231. ISSN 2231-2307. S2CID 11529467.
5. NECエレクトロニクス 8ビットマイコンのあゆみ [History of 8-bit microcontrollers of NEC Electronics] (PDF) (in Japanese). Sunhayato Corp.
6. "microcontroller". The Free Dictionary.
7. Oklobdzija, Vojin G. (2017). Digital Systems and Applications. CRC Press. ISBN 9781351838108.
8. "NEC Electronics Introduces 12 New 16-bit All Flash Microcontrollers with LCD Controller/Driver Circuit". Business Wire. 2009-01-16.
9. Garcia, Pedro Castillo; Lozano, Rogelio; Dzul, Alejandro Enrique (2006). Modelling and Control of Mini-Flying Machines. Springer Science & Business Media. ISBN 9781846281792.
10. Archived: . 7 October 2012. Archived from the original on 2012-10-07.
11. Emilio, Maurizio Di Paolo (2014). Embedded Systems Design for High-Speed Data Acquisition and Control. Springer. ISBN 9783319068657.
12. Electronic Specifier (2009-04-19). "NEC Electronics' new 78K Primer Kit". www.electronicspecifier.com.
13. Bender, Klaus; Jack, Peter; Koç, Ali; Péter, Istvan; Megyeri, Gergely (2001). Qualitätssicherung eingebetteter Software : Methoden und Best-Practices : [FUSIM] (in German). München: Herbert Utz Verlag. ISBN 9783831600243.
14. Renesas official: Renesas MPUs & MCUs 78K MCU Selection Guide. Renesas Electronics.
15. Dean, Alexander G.; Conrad, James M. (2012). Creating Fast, Responsive and Energy-Efficient Embedded Systems using the Renesas RL78 Microcontroller (PDF). Weston, FL: Micrium Press. ISBN 9781935772989.
16. Renesas official: Porting guide from 78K0R/FC3 to RL78/F14. Renesas Electronics.
17. "Renesas Electronics Introduces the New RL78 Microcontroller Family to Deliver Solutions for Next-Generation 8-/16-bit Embedded Applications". Renesas Electronics.
18. Hausmann, G.; Gebing, E. (1997). "The realisation of specific automotive applications with "Full" CAN functionality at "Basic" CAN cost on highly integrated 8-Bit microcontroller of NEC's 78K/0 family" (PDF). 4th International CAN Conference, ICC. 97: 4-02–11.
19. Renesas official: 78K/0 Series for Instructions. Renesas Electronics.
20. Renesas official: UPD78054,78054Y Subseries User's Manual. Renesas Electronics.
21. "NEC launches 14 new 8-bit MCUs for automotive dashboard applications | EE Times". EETimes.
22. Renesas official: 78K0/Dx2 User's Manual: Hardware. Renesas Electronics.
23. Suzuki, Tetsuya (2007-06-22). Google Translate - Introduction site of: Cコンパイラで遊ぶ78K0Sマイコン [Play with the C compiler 78K0S microcomputer]. www.socym.co.jp (in Japanese). Tokyo, Japan: Socym Co,.Ltd. ISBN 9784883375394.
24. Skorobogatov, Sergei (17 August 2010). Flash Memory 'Bumping' Attacks (PDF). Cryptographic Hardware and Embedded Systems, CHES 2010. Lecture Notes in Computer Science. Vol. 6225. Springer, Berlin, Heidelberg. pp. 158–172. doi:10.1007/978-3-642-15031-9_11. ISBN 9783642150319.
25. Renesas official: 78K/0S Series for Instructions. Renesas Electronics.
26. Renesas official: "Difference on 78K0 and 78K0S in 8-bit All Flash microcontrollers". Renesas Electronics - Knowledgebase. 28 June 2016.
27. Kim, Dahoo; Hida, Itaru; Fukuda, Eric S.; Asai, Tetsuya; Motomura, Masato (November 2014). A Study of Transparent On-chip Instruction Cache for NV Microcontrollers. The Seventh International Conference on Advances in Circuits, Electronics and Micro-electronics. pp. 26–29. CiteSeerX 10.1.1.676.6935. ISBN 978-1-61208-379-7. ISSN 2308-426X.
28. Renesas official: 78K0R Microcontrollers User's Manual: Instructions. Renesas Electronics.
29. Renesas official: RL78 family User's Manual: Software. Renesas Electronics.
30. 17K 4-bit Microcontroller Data Book (1992). NEC.
31. Renesas official: UPD178024 Subseries User's Manual. Renesas Electronics.
32. Renesas official: UPD179327 Subseries User's Manual. Renesas Electronics.
33. JPRS Report: Science & technology. Japan. Foreign Broadcast Information Service. 1994. p. 25.
    The 78K/IV has upward compatibility regarding the instruction sets of the existing 78K/0, 78K/II and 78K/III. Major features of the 78K/IV are: 1) linear addressing of 16 M bytes, 2) wide operative voltage = 2.7-6.0 V, 3) efficient power management, 4) instruction sets for C compiler. NEC has developed the 1st product “puPD784026 subseries” that has upward-compatible peripheral functions of the 78K/II series.
34. Ohuchi, Mitsurou; Kawata, Kazuhide; Akiyama, Shin-ichiro; Imamura, Hirohisa; Fukushima, Kiyoshi; Ishizaki, Norihiko; Imamizu, Jun-ichi; Mori, Takehiko; Ono, Hirohihiko; Nakata, Shigeru (1994). "16ビットシングルチップマイクロコンピュ-タ78K/4シリ-ズ (半導体デバイス)" [16-Bit Single Chip Microcomputer 78K/IV Series.]. NEC Technical Journal. 47 (3): 122–127.
35. "NEC: News Release 96/10/30-01". www.nec.co.jp.
36. "Micro Controller (Data Part)". www.cpe.ku.ac.th.
37. Renesas official: 78K/IV Series Instructions. Renesas Electronics.
38. Renesas official: UPD784908 Subseries Hardware (Preliminary). Renesas Electronics.
39. Lui, Dr. Gough (16 August 2013). "Salvage: Quantum Fireball 1280Mb AT Hard Drive". Gough's Tech Zone. Phto 2.
40. Renesas official: UPD78148 User's Manual. Renesas Electronics.
41. Renesas official: UPD78334 User's Manual. Renesas Electronics.
42. "Software repair of hard disks HDD (Google Translate)". www.phantom.sannata.ru (in Russian). 4X_Pro.
43. Renesas official: UPD78366A Hardware. Renesas Electronics.
44. Renesas official: UPD78234 Sub-Series Hardware. Renesas Electronics.
45. Renesas official: 87AD Series UPD78C18 User's Manual. Renesas Electronics.
46. 787012 User's Manual Hardware Edition (1994). NEC.
47. Renesas official: UPD78356 Instructions. Renesas Electrnics.

External links

• Technical documents
  • Application note: 78K/0 Series Basic (I) | Renesas Electronics
  • Application note: 78K/0 Series Basics(II) | Renesas Electronics
  • Application note: 78K/0 Series Basic (III) | Renesas Electronics
• Web sites
  • 78K Family | Renesas Electronics
  • 78K Family Software & Tools | Renesas Electronics
  • CPU of the Day: NEC 78C11 Sample and the 78K family | The CPU Shack MUseum
  • TESSERA TECHNOLOGY, Inc.