Overview of the Casio PV-7
In 1984, Casio released it's first MSX Computer in Japan, the Casio PV-7. The PV-7 has what is known as a chicklet keyboard (a keyboard without full-stroke keys) but does have cursor keys arranged in a joypad fashion for easy game-play. There are two keys that are the equivalent of the joystick fire buttons 1 and 2 and the cursor keys are repeated at the top in normal style. The Casio PV-7 came in black and red.
With 8kB RAM, no printer port, and one cartridge slot, it barely meets the MSX1 standard. An expansion unit (KB-7) was available, that added 8kByte of RAM and two extra cartridge slots. The 8K RAM is sufficient to play games on cartridges, but this computerwill lack memory to play games from other mediums such as tape. There is an active fan scene that has provided several options to expand the Casio PV-7 to an internal 16K of RAM.
MSX was announced by Microsoft and the ASCII Corporation on June 16th 1983. It was marketed by Kasuhiko Nishi, who was Vice-President at Microsoft and a director at the ASCII Corporation. MSX was an attempt to create a hardware and software standard among various home computers, similar to what VHS had accomplished for the Home Video market.The MSX Standard defines specifications for:
- CPU and Memory
- Video Output hardware
- Audio hardware
- Cassette and Disk drives
- Keyboard, mouse and joysticks
- Expansion and I/O ports
The standard became a success in Japan, with many big software houses such as Konami creating games for it. Outside of Japan, the adoption rate was low. In the USA, Microsoft actively pushed the PC compatibles, since they sold the operating system for it, and in Europe the MSX computers had stiff competition from Commodore and Atari. The Netherlands and Spain have the highest rates of MSX users in Europe.
MSX Cassette Pin Layout
The MSX Standard calls for all MSX computers to have a standard data-cassette port. This port transports the audio-in/out signals to and from the datarecorder and the computer has a relay-switch on board to turn the recorder on and off.
MSX Cartridge Connector
The MSX Cartridge system uses a 50-pin flat-edge connector to connect to the systems expansion bus. The cartridge slot maps into one of the main- or sub-slots.
TMS9918 Series Video Display Processor (99n8, 99n9, 91n8, 91n9)
The TMS9918 is a series of video display controllers (VDC) manufactured in 1979 by Texas Instruments, also refered to as 'Video Display Processor' (VDP). The TMS9918 and its variants were used in the ColecoVision, CreatiVision, Memotech MTX, MSX, NABU Personal Computer, SG-1000/SC-3000, Spectravideo SV-318, Spectravideo SV-328, Sord M5, Tatung Einstein, Texas Instruments TI-99/4, Casio PV-2000, Coleco Adam, Hanimex Pencil II, and Tomy Tutor.
- 256x192 pattern based color pixels per screen
- 16 different colors
- 8-bit memory mapped CPU interface
- No need for DMA, CPU can access VRAM
- 32 single color Sprites per screen (4 per scanline)
- TMS9918A - 60Hz output, NTSC video
- TMS9928A - 60Hz output, YPbPr video
- TMS9929A - 50Hz output, YPbPr video
- TMS9118 - Different RAM than TMS9918A, otherwise identical
- TMS9128 - Different RAM than TMS9928A, otherwise identical
- TMS9129 - Different RAM than TMS9929A, otherwise identical
Programmable Sound Generator (AY-3-8910 compatible PSG)
The AY-3-8910 is a 3-voice Programmable Sound Generator, or PSG. It was designed by General Instrumet 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:
- Amstrad CPC range
- 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.
Comes with 2 general purpose 8-bit parallel I/O ports, used for Keyboard and Joystick in for instance MSX.
Same chip, but in a 28-pin package. Parallel port B is not connected to save cost and space.
Same chip, but in a 24-pin package. Both parallel ports are not connected.
Backwards compatible but BC2 pin is ignored
CMOS version of the Y2149 in 40-pin DIP
CMOS version of the Y2149 in 44-pin QFP
Variant of the YM3249 in an 18-pin package. Parallel ports not connected, and all sound channels mixed on 1 port.
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.
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.
Zilog Z80 CPU Family
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.
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 design was licensed to Synertek and Mostek as well as the European SGS.
The Z80s instruction set is binary compatible with the Intel 8080, so that 8080 code such as the CP/M Operating System and Intel's PL/M compiler for the 8080 can run unmodified on the Z80. The Z80 had many enhancements over the 8080 such as 16-bit data movement instructions, block copy and block I/O instructions, single bit addressing of all registers, IX/IY offset registers, better interrupt system and a complete duplicate register file for context switching during an interrupt.Source: WikiPedia
32x24 16 color text, pattern based
256x192 16 color, 2 color per 8 pix. Sprites 1 color, 16x16, 4/scanline, 32 total System OS MSX 1 BIOS, MSX BASIC Storage External Tape, ROM cartridges