Browse Prior Art Database

Speech Output Display Terminal

IP.com Disclosure Number: IPCOM000042144D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Barnett, CJ: AUTHOR [+5]

Abstract

This article describes a means of monitoring the change of status in the indicator row of a display. An interrupt to a microprocessor system informs it of the change. The general data flow of dynamic monitoring is shown in the figure. The microprocessor can read the data from a special indicator row buffer for further processing. The microprocessor must be informed when there is a change of status in the indicator row, and must be able to read the data. The indicator row on this display contains display, controller, and system status. In this application there is no simple direct access path to the data store. The data must be obtained from the display as it is sent to the screen for refresh.

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Speech Output Display Terminal

This article describes a means of monitoring the change of status in the indicator row of a display. An interrupt to a microprocessor system informs it of the change. The general data flow of dynamic monitoring is shown in the figure. The microprocessor can read the data from a special indicator row buffer for further processing. The microprocessor must be informed when there is a change of status in the indicator row, and must be able to read the data. The indicator row on this display contains display, controller, and system status. In this application there is no simple direct access path to the data store. The data must be obtained from the display as it is sent to the screen for refresh. Due to the fast scan rate [*] of a refresh type display, most microprocessors cannot issue I/O read commands fast enough to extract data from the refresh data stream as it is refreshed. Circuitry synchronized with the scan rate of the display, but under control of the microprocessor, interfaces between the display and the microprocessor. Data from the indicator row on the display screen is loaded into a special indicator row buffer during refresh, and can then be read out by the microprocessor at any speed determined by the microprocessor. A counter, the character counter, is used in the interface. Except when data is being read by the microprocessor, it counts in synchronism with the refresh data on the display. When the microprocessor reads the data from the indicator row buffer, the counter increments each time the microprocessor reads a byte from the row buffer. The counter counts up once for each character positi...