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Display controller

  • US 4,760,387 A
  • Filed: 01/31/1986
  • Issued: 07/26/1988
  • Est. Priority Date: 03/19/1985
  • Status: Expired due to Term
First Claim
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1. A display controller capable of selectively driving a selected one of a first and a second display unit, the first display unit having a display screen comprised of a scanning-type screen which provides M rows of N columns of display positions thereon, the second display unit having a display screen constituted by upper and lower scanning-type screens, each of which provides P rows of Q columns of display positions thereon, the display controller being further connected to memory means having a plurality of addresses, each for storing display data relating to an image to be displayed at a respective one of the display positions of the selected display unit, said display controller comprising:

  • (a) display unit designating means for designating one of said first and second display units, said designation means producing a first designation signal when the first display unit is selected, and producing a second designation signal when the second display unit is selected;

    (b) tiiming signal generating means, responsive to said first designation signal, for generating first synchronization signals is response to said first designation signal to be supplied to the first display unit for scanning the screen thereof, said timing signal generating means being further responsive to said second designation signal to generate second synchronization signals in response to said second designation signal, to be supplied to the second display unit for scanning the upper and lower screens thereof;

    (c) address data generating means, responsive to said first designation signal, for generating a first series of address data representative of addresses of the memory means and sequentially outputting said generated address data to the memory means in accordance with the scanning of the display screen of the first display unit, said address data generating means being further responsive to said second designation signal for generating a second series of address data representative of those of the addresses of the memory means corresponding to the upper screen and a third series of address data representative of those of the addresses of the memory means corresponding to the lower screen, said address data generating means alternately outputting, responsive to said second designation signal, each of said second series of address data and each of said third series of address data to the memory means in accordance with scanning of the upper and lower screens; and

    (d) display signal generating means, responsive to said first designation signal for generating a first display signal to be supplied to the first display unit based on data read from the memory means in accordance with said first series of address data, said display signal generating means being further responsive to said second designation signal to generate second and third display signals to be supplied to the second display unit based on data read from the memory means in accordance with said second and third series of address data, said second and third display signals being used to display images on the upper and lower screens of said second display unit, respectively.

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