Difference between revisions of "MC6845"
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| − | 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 | + | 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 standalone or cluster configurations. The CRTC is optimized for hardware/software balance in order to achieve integration of all key functions and maintain flexibility. For instance, all keyboard functions, R/W, cursor movements, and editing are under processor control; whereas the CRTC provides video timing and Refresh Memory Addressing. |
| − | • Applications include "glass-teletype," smart, programmable, | + | • Applications include "glass-teletype," smart, programmable, intelligent CRT terminals; video games; information display. |
• Alphanumeric, semi-graphic, and full graphic capability. | • Alphanumeric, semi-graphic, and full graphic capability. | ||
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• Hardware scroll (paging or by line or by character). | • Hardware scroll (paging or by line or by character). | ||
| − | • Compatible with CPU's and MPU's which provide a means | + | • Compatible with CPU's and MPU's which provide a means for synchronizing external devices. |
• Cursor register and compare circuitry. | • Cursor register and compare circuitry. | ||
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• Light pen register. | • Light pen register. | ||
| − | • Line buffer-less operation. No external DMA required. | + | • Line buffer-less operation. No external DMA required. Refresh Memory is multiplexed between CRTC and MPU. |
• Programmable Interlace or non-interlace scan. | • Programmable Interlace or non-interlace scan. | ||
Latest revision as of 01:28, 6 August 2014
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 standalone or cluster configurations. The CRTC is optimized for hardware/software balance in order to achieve integration of all key functions and maintain flexibility. For instance, all keyboard functions, R/W, cursor movements, and editing are under processor control; whereas the CRTC provides video timing and Refresh Memory Addressing.
• Applications include "glass-teletype," smart, programmable, intelligent 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 for synchronizing external devices.
• Cursor register and compare circuitry.
• Cursor format and blink are programmable.
• Light pen register.
• Line buffer-less operation. No external DMA required. Refresh Memory is multiplexed between CRTC and MPU.
• Programmable Interlace or non-interlace scan.
• 14-bit wide refresh address
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