78K



78K is the trademark name of 16- and 8-bit microcontroller family manufactured by Renesas Electronics, originally developed by NEC started in 1986. 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.

Its application area is mainly simple mechanical system controls and man-machine interfaces.

Regarding software development tools, C compilers and macro-assemblers are available. As for development tool hardware, full probing-pod type and debug port type in-circuit emulators, and flash ROM programmers 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. But in most of cases, migration to RL78 Family, which is a successor of 78K0R and almost binary level compatible with 78K0R, is recommended.

78K0 Series
78K0 Series (also known as 78K/0) is a long-running 8-bit single chip microcontroller, 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. 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. But with the times, it became flash memory.

78K0S Series
78K0S Series (also known as 78K/0S) is a low-end version of 78K0. 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.

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

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. It integrates 17K family's peripheral functions with the 78K0 8-bit CPU core on a chip.

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

78K4 Series
78K4 Series (also known as 78K/4) is a 16-bit single-chip microcontroller with 16 and 8-bit operations. 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. It has 24-bit 16M Byte address space. It has microcode-based operations named Macro Service with interrupt functions.

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, 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.

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.

This series is used for hard disk drives, especially Quantum Fireball Series. μPD78364 sub-series is used for inverter compressor controls. 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.

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

17K Family
17K Family 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.