Arrangement and method of accessing frame buffer in raster-scan type computer system

摘要

A multiple-plane frame buffer is effectively accessed which is provided in a video signal generator in a raster-scan type computer system. The video signal generator further includes a video controller preceded by the multiple-plane frame buffer. The video controller receives multiple-bit-per-pixel data from the multiple-plane frame buffer and applies three primary analog data to a raster-scan display. There is provided a pixel data writing controller which is arranged to store a first multiple-bit-per-pixel data defining each color of image pixels and a second multiple-bit-per-pixel data defining each color of background pixels. The pixel data writing controller selectively applies one of the first and second multiple-bit-per-pixel data to the multiple-plane frame buffer in response to a control signal applied thereto.