Browse Prior Art Database

Backspace and Erase Function for a Dynamic Display Device

IP.com Disclosure Number: IPCOM000075010D
Original Publication Date: 1971-Jul-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Steward, EH: AUTHOR [+2]

Abstract

The function of backspacing and erasing the last character entered, when keying characters into a display, can be solved by the following method.

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Backspace and Erase Function for a Dynamic Display Device

The function of backspacing and erasing the last character entered, when keying characters into a display, can be solved by the following method.

The characters displayed are stored in a shift register which acts like a delay line buffer (see Fig. 1). That is, all the bits are stored serially in the register. They are deserialized in a one-character shift register for the display device. This serial stream of bits is synchronized with the display, and is shifted at such a rate that the display is refreshed fast enough not to cause a flicker effect for the viewer. That is, a complete scan is made in less than 1/30 of a second.

The characters stored in the shift register are coded such that only one character is unique and is called RESET. When this character is detected during deserialization of the data, it is not displayed but rather it resets the display and all control logic in order to initiate a new scan for the display. This action occurs often enough, (less than 1/30 of a second) in order to achieve a flicker free display.

To perform the backspace function, it must be understood that after the "last character entered" is deserialized, the RESET character will be deserialized and detected. In order to backspace, it is only necessary to replace the "last character entered" with a RESET character and then erase the original RESET character. Thus, the display will effectively be backspaced.

To perform t...