The HuC6280

8-bit In computer architecture, 8-bit integers or other data units are those that are 8 bits wide (1 octet). Also, 8-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers or data bu ...

microprocessor A microprocessor is a computer processor (computing), processor for which the data processing logic and control is included on a single integrated circuit (IC), or a small number of ICs. The microprocessor contains the arithmetic, logic, a ...

is Japanese company

Hudson Soft was a Japanese video game company known for releasing numerous titles across video game consoles, home computers, and mobile phones. Headquartered in the Midtown Tower in Tokyo, it also maintained an office in the Hudson Building in Sapporo. F ...

's improved version of the

WDC 65C02 The Western Design Center (WDC) 65C02 microprocessor is an enhanced CMOS version of the popular nMOS-based 8-bit MOS Technology 6502. It uses less power than the original 6502, fixes several problems, and adds new instructions and addressing ...

CPU A central processing unit (CPU), also called a central processor, main processor, or just processor, is the primary processor in a given computer. Its electronic circuitry executes instructions of a computer program, such as arithmetic, log ...

, an upgraded CMOS version of the popular NMOS-based

MOS Technology 6502 The MOS Technology 6502 (typically pronounced "sixty-five-oh-two" or "six-five-oh-two") William Mensch and the moderator both pronounce the 6502 microprocessor as ''"sixty-five-oh-two"''. is an 8-bit computing, 8-bit microprocessor that was desi ...

8-bit CPU, manufactured for Hudson by

Seiko Epson Seiko Epson Corporation, commonly known as Epson, is a Japanese multinational electronics company and one of the world's largest manufacturers of printers and information- and imaging-related equipment. Headquartered in Suwa, Nagano, Japan, t ...

and

NEC is a Japanese multinational information technology and electronics corporation, headquartered at the NEC Supertower in Minato, Tokyo, Japan. It provides IT and network solutions, including cloud computing, artificial intelligence (AI), Inte ...

. The most notable product using the HuC6280 is

TurboGrafx-16 The TurboGrafx-16, known in Japan as the , is a home video game console developed by Hudson Soft and manufactured by NEC. It was released in Japan in 1987 and in North America in 1989. The first console of the fourth generation of video game con ...

video game console A video game console is an electronic device that Input/output, outputs a video signal or image to display a video game that can typically be played with a game controller. These may be home video game console, home consoles, which are generally ...

Description

The HuC6280 contains a

65C02 The Western Design Center (WDC) 65C02 microprocessor is an enhanced CMOS version of the popular nMOS-based 8-bit MOS Technology 6502. It uses less power than the original 6502, fixes several problems, and adds new instructions and addressing mo ...

core which has several additional instructions and a few internal peripheral functions such as an

interrupt controller In computing, a programmable interrupt controller (PIC) is an integrated circuit that helps a microprocessor (or CPU) handle interrupt requests (IRQs) coming from multiple different sources (like external I/O devices) which may occur simultane ...

, a

memory management unit A memory management unit (MMU), sometimes called paged memory management unit (PMMU), is a computer hardware unit that examines all references to computer memory, memory, and translates the memory addresses being referenced, known as virtual mem ...

, a

timer A timer or countdown timer is a type of clock that starts from a specified time duration and stops upon reaching 00:00. It can also usually be stopped manually before the whole duration has elapsed. An example of a simple timer is an hourglass ...

, an 8-bit parallel I/O port, and a

programmable sound generator A programmable sound generator (PSG) is a sound chip that generates (or synthesizes) audio wave signals built from one or more basic waveforms, and often some kind of noise. PSGs use a relatively simple method of creating sound compared to other m ...

(PSG). The processor operates at two speeds, 1.79 MHz and 7.16 MHz. A slightly revised HuC6280A was released and used in the PC Engine CoreGrafx and

SuperGrafx The , also known as simply the SuperGrafx, is a fourth-generation home video game console manufactured by NEC Home Electronics and released in Japan in 1989. It is the successor system to the PC Engine, released two years prior. Originally kn ...

. This revision reportedly fixed some minor audio issues in those systems.

Memory mapping

Source:https://github.com/MiSTer-devel/TurboGrafx16_MiSTer/blob/master/docs/HuC6280%20-%20CMOS%208-bit%20Microprocessor%20Hardware%20Manual.pdf The HuC6280 has a 64 KB

logical address In computing, a logical address is the address at which an item ( memory cell, storage element, network host) appears to reside from the perspective of an executing application program. A logical address may be different from the physical addr ...

space, but a 2 MB physical address space. The HuC6280 uses a

Memory Management Unit A memory management unit (MMU), sometimes called paged memory management unit (PMMU), is a computer hardware unit that examines all references to computer memory, memory, and translates the memory addresses being referenced, known as virtual mem ...

that splits the memory space into segments of 8 KB. Each logical 8 KB segment is associated with one of 256 physical 8 KB sized segments. This can be set up with an 8-bit register (MPR0-7) that contains the most significant eight bits of the address of the 8 KB segment in physical memory. Thus the logical 64 KB address space can be overlapping, continuous or scattered in physical address space, depending on the eight MPR registers. Two special instructions are used to access these registers: TAMi - transfer the content of the accumulator (A) into an MPR register (0-7). TMAi - transfer an MPR register into the accumulator.

Sound generator

PSG-styled

wavetable synthesis Wavetable synthesis is a sound synthesis technique used to create quasi-periodic waveforms often used in the production of musical tones or notes. Development Wavetable synthesis was invented by Max Mathews in 1958 as part of MUSIC II. MU ...

provides six sound channels, which can be conveniently paired according to the functionality they provide: 0-1 - Waveform playback Frequency modulation (channel 1 muted) 2-3 - Waveform playback only 4-5 - Waveform playback White noise generation Waveform playback is the most common and allows a 32-byte, 5-bit unsigned linear sample to be played back at selected frequencies.

Frequency modulation Frequency modulation (FM) is a signal modulation technique used in electronic communication, originally for transmitting messages with a radio wave. In frequency modulation a carrier wave is varied in its instantaneous frequency in proporti ...

takes this one step further, allowing the playback frequency to be dynamically adjusted according to a specified pattern.

White noise In signal processing, white noise is a random signal having equal intensity at different frequencies, giving it a constant power spectral density. The term is used with this or similar meanings in many scientific and technical disciplines, i ...

is used to simulate percussion instruments and effects, such as explosions, by means of a pseudo-random

square wave Square wave may refer to: *Square wave (waveform) A square wave is a non-sinusoidal waveform, non-sinusoidal periodic waveform in which the amplitude alternates at a steady frequency between fixed minimum and maximum values, with the same ...

. Alternatively, each channel can be individually switched to "Direct D/A" mode in which the programmer can send data directly to the sound mixer, allowing more complex sound patterns to be generated, such as speech. Inevitably, this requires more programming effort and CPU time.

References

External links

*http://shu.emuunlim.com/download/pcedocs/pce_cpu.html *http://www.magicengine.com/mkit/ *http://www.interlog.com/~daves/pce_info/info.html *https://www.copetti.org/writings/consoles/pc-engine/ {{NEC video game consoles 65xx microprocessors TurboGrafx-16 Hudson Soft