Motorola 6845

The Motorola 6845 (commonly MC6845) is a video address generator first introduced by Motorola and used among others in the Videx VideoTerm display cards for the Apple II computers, in the MDA, HGC and CGA video adapters for the IBM PC, and in the Amstrad CPC and BBC Micro. Its functionality was duplicated and extended by custom circuits in the EGA and VGA PC video adapters. It is related to the later 6545 manufactured by MOS Technology (Commodore Semiconductor Group) and Rockwell (in two variations) and was cloned as the Hitachi HD46505 which was used in many Japanese computers from Sony, Sharp, Panasonic and Casio, and later was used in Videx's UltraTerm card).

It is also known as the 6845 CRTC or the CRTC6845, meaning "cathode ray tube controller".

Although intended for designs based on the Motorola 6800 CPU and given a related part number, it was more commonly used alongside various other processors.

Overview

The chip generates the signals necessary to interface with a raster display but does not generate the actual pixels, though it does contribute cursor and video-blanking information to the pixel video (intensity) signals. It is used to produce correctly timed horizontal and vertical sync and provide the address in memory from which the next pixel or set of pixels should be read. The process of reading that value, converting it into pixels, and sending it to a CRT is left to other circuits. Because of this, systems using the 6845 may have very different numbers and values of colors, or may not support color at all.

Canadian Radio-television and Telecommunications Commission

The Canadian Radio-television and Telecommunications Commission (CRTC, French: Conseil de la radiodiffusion et des télécommunications canadiennes) is a public organisation in Canada with mandate as a regulatory agency for broadcasting and telecommunications. It was created in 1976 when it took over responsibility for regulating telecommunication carriers. Prior to 1976, it was known as the Canadian Radio and Television Commission, which was established in 1968 by the Parliament of Canada to replace the Board of Broadcast Governors. Its headquarters is located in the Central Building (Édifice central) of Les Terrasses de la Chaudière in Gatineau, Quebec.

History

The CRTC was originally known as the Canadian Radio-Television Commission. In 1976, jurisdiction over telecommunications services, most of which were then delivered by monopoly common carriers (for example, telephone companies), was transferred to it from the Canadian Transport Commission although the abbreviation CRTC remained the same.

Carotenoid 1,2-hydratase

Carotenoid 1,2-hydratase (EC 4.2.1.131, CrtC) is an enzyme with system name lycopene hydro-lyase (1-hydroxy-1,2-dihydrolycopene-forming). This enzyme catalyses the following chemical reaction

In Rubrivivax gelatinosus and Thiocapsa roseopersicina both products are formed.

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