The Toshiba Pasopia 5 is a computer from manufacturer Toshiba, released in 1983 and based around a Z80 microprocessor. Also known as PA7005, it was released only in Japan, intended as a low price version of the original Toshiba Pasopia.

The keyboard has 90 keys, a separate numeric keypad and eight function keys. The machine could be expanded with disk drives, extra RAM and offered a RS-232 interface and a parallel printer port. The machine is compatible with the original Pasopia.

The Toshiba Pasopia 5 incorporates 64 KB of main RAM A distinctive feature of its internal design is the inclusion of 48 KB of dedicated Video RAM (VRAM) which is managed by a discrete video controller. This allows the system to output a maximum resolution of 640 × 200 pixels in monochrome mode or a high-density 320 × 200 pixels in 8-color mode, which was a competitive specification for Japanese 8-bit systems of the era.

The Pasopia 5 utilizes a sophisticated memory-management unit (MMU) to handle the overlap between its 32 KB system ROM and the primary 64 KB RAM. The system ROM contains the T-BASIC (Toshiba BASIC) interpreter, which is based on the Microsoft BASIC dialect but includes specific extensions for the Pasopia 5's unique hardware registers. I/O operations and peripheral management are facilitated by a series of Large Scale Integration (LSI) components, including a Toshiba T7710 for video generation and sound. The audio subsystem provides three independent sound channels plus a noise generator, frequently driven by a General Instrument AY-3-8910 or a functionally equivalent internal controller, depending on the specific revision of the motherboard.

For storage and expansion, the Pasopia 5 features two proprietary slots and a standard centronics-style parallel printer port. A critical component of the Pasopia 5's ecosystem is the PAC-2 expansion, which facilitates connection to external 5.25-inch floppy disk drives. When equipped with these drives, the machine can run the CP/M 2.2 operating system, shifting it from a BASIC-centric hobbyist machine to a more capable business-oriented platform. The disk controller interface utilizes a Western Digital FD1793 or similar FDC chip, managing high-density disk formats through a dedicated I/O port address range.

The keyboard utilizes a mechanical switch design with a full QWERTY layout and a dedicated numeric keypad. On the rear panel, the system provides both RGB (digital) and composite video outputs, alongside a DIN-style cassette interface for data storage at 1200 baud. The hardware design emphasizes modularity through its back-panel ports, allowing for the attachment of specialized modules such as RS-232C serial interfaces for telecommunications, which were addressed through the Z80’s `IN` and `OUT` instruction set at specific port offsets.

The Toshiba T7710 is a proprietary Video Display Controller (VDC) developed specifically for Toshiba’s 8-bit computer ecosystem, most notably the Pasopia 5 and Pasopia 7 series. Architecturally, it is designed to offload complex raster generation from the Zilog Z80A CPU, managing a dedicated pool of up to 48 KB of Video RAM (VRAM). The chip functions as a programmable timing generator and attributes controller, capable of driving both digital RGB and composite video signals. It supports multiple display modes, ranging from standard 40-column text to high-resolution bitmapped graphics of 640 × 200 pixels. In its color modes, the T7710 handles an 8-color palette (Black, Blue, Red, Magenta, Green, Cyan, Yellow, White) by assigning specific bit-planes within the VRAM to color attributes.

The T7710 interfaces with the system bus via a set of internal registers mapped to I/O ports, typically at $10 (Address/Status) and $11 (Data) in the Pasopia series. It features an internal character generator ROM for text modes but allows the CPU to redefine character patterns or switch to a full "Graphics" mode where every pixel is individually addressable. A critical technical aspect of the T7710 is its VRAM banking logic; because the Z80A can only address 64 KB of total memory, the T7710 manages the switching of 16 KB VRAM blocks into the CPU's address space. This allows the processor to update background buffers or draw complex sprites without interfering with the active display scan, provided the programmer correctly manages the bank-switching latencies.

The internal logic of the T7710 also incorporates hardware-level synchronization for the General Purpose Interface Bus (GPIB) and other timing-critical I/O found on Toshiba's professional-grade 8-bit hardware. It generates the Horizontal Sync (HSYNC) and Vertical Sync (VSYNC) pulses required for NTSC-standard monitors, and in specialized configurations, it can support a "Superimpose" mode. This mode allows the chip to synchronize its internal dot clock with an external video source, enabling the computer's graphics to be overlaid on top of a live video signal—a precursor to modern desktop video editing capabilities.

The AY-3-8910 is a 3-voice Programmable Sound Generator, or PSG. It was designed by General Instruments in 1978 for use with their own 8-bit PIC1650 and their 16-bit CP1610 computers.

The PSG is widely used in many arcade cabinets, pinball machines, and many micro-computers. Here is a list of some of the major brands of computer that used the AY-3-8910:

• Intellivision
• Vectrex
• Amstrad CPC range
• Oric-1
• Color Genie
• Elektor TV Games Computer
• All MSX-1 and MSX-2 computers
• ZX Spectrum home computers

General Instrument spun of MicroChip Technology in 1987 and the chip was sold under the MicroChip brand, and licensed to Yamaha as the YM2149F which the Atari ST range of computers use. Functionally the PSG is very similar to the Texas Instruments SN76489.

Variants:

• AY-3-8910
  Comes with 2 general purpose 8-bit parallel I/O ports, used for Keyboard and Joystick in for instance MSX.
• AY-3-8912
  Same chip, but in a 28-pin package. Parallel port B is not connected to save cost and space.
• AY-3-8913
  Same chip, but in a 24-pin package. Both parallel ports are not connected.
• AY-3-8914
  The AY-3-8914 has the same pinout and is in the same 40-pin package as the AY-3-8910, except the control registers on the chip are shuffled around, and the 'expected input' on the A9 pin may be different. It was used in Mattel's Intellivision console and Aquarius computer.
• AY-3-8930
  Backwards compatible but BC2 pin is ignored
YM2149F
Yamaha Produced chip, same pin-out as the AY-3-8910, but pin 26 could halve the master clock. Can be used to replace the AY-3-8910 if pin 26 is left disconnected.
• YM3439-D
  CMOS version of the Y2149 in 40-pin DIP
• YM3439-F
  CMOS version of the Y2149 in 44-pin QFP
• YMZ294
  Variant of the YM3249 in an 18-pin package. Parallel ports not connected, and all sound channels mixed on 1 port.
• T7766A
  Toshiba variant of the AY-3-8910, fully compatible. Used in some MSX models.
• Winbond WF19054, JFC95101, and File KC89C72: Fully compatible versions of the AY-3-8910 produced for slot machines.

The Z80 quickly became popular in the personal computer market, with many early personal computers, such as the TRS-80 and Sinclair ZX80, using the Z80 as their central processing unit (CPU). It was also widely used in home computers, such as the MSX range, SORD, and the Amstrad CPC, as well as in many arcade games. Additionally, it was also used in other applications such as industrial control systems, and embedded systems. The Z80 was widely used until the mid-1980s, when it was gradually replaced by newer microprocessors such as the Intel 80286 and the Motorola 68000.

The Z80 microprocessor was developed by Zilog, a company founded by Federico Faggin in 1974. The Z80 was released in July 1976, as a successor to the Intel 8080. It was designed to be fully compatible with the 8080, but also included new features such as an improved instruction set, more powerful interrupts, and a more sophisticated memory management system.

Originally the Z80 was intended for use in embedded systems, just as the 8080 CPU. But the combination of compatibility, superior performance to other CPUs of the era, and the affordability led to a widespread use in arcade video game systems, and later in home computers such as the Osborne 1, TRS-80, ColecoVision, ZX Spectrum, MSX, Sega's Master System and many more. The Z-80 ran the original Pac-Man arcade cabinet. The Z-80 was used even in the Game Gear (1990s), and the TI-81 and succeeding graphic calculators.

The Z-80 remained in production until June of 2024, 48 years after its original release. Zilog replaced the processor with its successor the eZ80, an 8-bit microprocessor that features expanded memory addressing up to 16 megabytes, and running up to 50MHz, comparable to a Z80 clocked at 150MHz.