Amiga Hombre chipset
Hombre is a RISC chipset for the Amiga designed by Commodore, intended as the basis of its next generation game machine called CD64.[1]
Commodore also planned to build a 3D accelerator PCI card based on Hombre. Hombre was canceled along with the bankruptcy of Commodore International.
Contents
History
In 1993, Commodore International ceased the development of the AAA chipset and began to design a new 64-bit 3D graphics chipset based on Hewlett-Packard's PA-RISC architecture to serve as the new basis of the Amiga personal computer series. It was codenamed Hombre (pronounced "ómbre" which means man in Spanish) and was developed in conjunction with over an estimated eighteen-month period.
Backward compatibility
Hombre does not support any planar mode, nor any emulation for the legacy Amiga chipset or Motorola 680x0 CPU registers, so it was completely incompatible with former Amiga models. According to Hombre designer Dr. Ed Hepler, Commodore intended to produce an AGA Amiga upon a single chip to solve the backward compatibility issues. This single chip would include Motorola MC680x0 core, plus the AGA chipset. The chip could be integrated in Hombre based computers for backward compatibility with AGA software.[2]
Design
Hombre is based around two chips: a System Controller chip and a Display Controller chip.
The System Controller chip was designed by Dr. Ed Hepler, well known as the designer of the AAA Andrea chip. The chip is similar in principle to the chip bus controller found in Agnus, Alice, and Andrea of the Amiga chipsets. The chip features the following:
- A 100+ MHz PA-7150 SIMD microprocessor
- An advanced DMA engine and blitter with 3D texture mapping and gouraud shading
- 16-bit resolution sound processor with eight voices
The Display Controller Chip was designed by Tim McDonald, also known as the designer of the AAA Monica chip. It is similar in principle to the Denise, Lisa, and Monica chips found on original Amigas. In addition, the chipset also supported future official or third party upgrades through extension for an external PA-RISC processor.
These chips and some other circuitry would be part of a PCI card, through the ReTargetable Graphics system.
There were plans to port the AmigaOS Exec kernel to low-end systems, but this was not possible due to financial troubles facing Commodore at that time. Therefore, a licensed OpenGL library was to be used for the low-end entertainment system.
The original plan for the Hombre-based computer system was to have Windows NT compatibility, with native AmigaOS recompiled for the new big-endian CPU to run legacy 68k Amiga software through emulation. Commodore chose the PA-7150 microprocessor over the MIPS R3000 microprocessor and first generation embedded PowerPC microprocessors, mainly because these low-cost microprocessors were unqualified to run Windows NT. This wasn't the case for the 64-bit MIPS R4200, but it was rejected for its high price at the time.
Features
Hombre was designed as a clean break from traditional Amiga chipset architecture with no planar graphics mode support. Commodore also decided to drop support of the original Amiga eight sprites because at the time sprites became less attractive to developers for its limitations compared to fast blitters. Despite lack of compatibility, Hombre introduced modern technologies including these:
- a fill rate of 30 million 3D rendered pixels per second (similar to Sony's PlayStation performance)
- 16-bit chunky graphic modes (to reduce costs, Commodore abandoned 256 color mode with Color LUT registers)
- 32-bit chunky with 8-bit alpha channel
- 1280 × 1024 pixel progressive resolution with a 24-bit color palette
- one sprite with a 24-bit color palette, used for the mouse pointer
- four playfields at 16-bit graphics mode each
- 3D texture mapping engine
- Gouraud shading
- Z-buffering
- YUV compatibility with JPEG support
- Standard TV and HDTV compatibility
- 64-bit internal data bus and registers
The chipset could be sold either as a high end PCI graphics card with minimal peripherals ASICs and 64-bit DRAM, or as a lower cost CD-ROM based game system (CD64) using cheap 32-bit DRAM. It could also be used for set-top box embedded systems.
According to Dr. Ed Hepler, Hombre was to be fabricated in 0.6 µm 3-level metal CMOS with the help of Hewlett-Packard. HP had fabricated the AGA Lisa chip and collaborated in the design of the AAA chipset).
Commodore was planning to adopt the Acutiator architecture designed by Dave Haynie for Hombre before it filed bankruptcy and went out of business.
