The LR33020 GraphX processor: a single chip X-terminal controller

A description is given of the LR33020 GraphX processor, an application-specific version of the MIPS R3000 architecture designed specifically for X-terminal systems. Beginning with the R3000 CPU core, the LR33020 integrates caches, write buffers, and memory controllers with dedicated hardware graphics support. Features incorporated into the graphics portion of the device include a BitBLT coprocessor, DMA channels, 64-b data path, programmable video timing, video FIFO, PS/2 style port, and direct support for Ethernet and other off-chip peripheral devices. The LR33020 can be configured as a monochrome, 2- or 4-b grayscale, or 8-, 16- or 32-b color controller. By coupling a high-performance RISC (reduced instruction set computer) CPU with dedicated graphics functions, the LR33020 offers a high-performance yet cost-effective controller for third-generation X-terminal systems.<>