ocr: 4.5.2 DHA TIMING The 7360 performs IMA's to fetch additional infornation to maintsin a video display, Twice Per each row of charactersi (a character being defined as a cell 8 X 8 bits) to obtain the attributes for each character and to obtain the character pointer which Points to where the charcter Patterni cen be found. In bit map noder these DMA's still occur: but the information is interpretted differently. The seQuerice of events if1 a DMA cycle are: 1)The system clock cones out of double sreed for 1 cycle, At the same time AEC starts to tossle, sllowins the 7360 on the bus. 2)The Bus Avai ...
