MC6845

The MC6845 CRT Controller performs the interface to raster scan CRT displays. It is intended for use in processor-based controllers for CRT terminals in stand-alone or cluster configurations. The CRTC is optimized for hardware/software balance in order to achieve integration of all key functions and maintain flexibility. Forinstance, all keyboard functions, R/W, cursor movements, and editingare under processor control; whereas the CRTC provides video timing and Refresh Memory Addressing.

• Applications include "glass-teletype," smart, programmable, intel-ligent CRT terminals; video games; information display. • Alphanumeric, semi-graphic, and full graphic capability. • Fully programmable via processor data bus. Can generate timing for almost any alphanumeric screen density, e.g. 80 x 24, 72 x 64,132 x 20, etc. • Single +5 volt supply. TTL/6800 compatible I/O. • Hardware scroll (paging or by line or by character) • Compatible with CPU's and MPU's which provide a means forsynchronizing external devices. • Cursor register and compare circuitry. • Cursor format and blink are programmable. • Light pen register. • Line buffer-less operation. No external DMA required. RefreshMemory is multiplexed between CRTC and MPU. • Programmable Interlace or non-interlace scan. • 14-bit wide refresh address