Browse Prior Art Database

Multiple Character Generators for Data Overlay

IP.com Disclosure Number: IPCOM000047003D
Original Publication Date: 1983-Sep-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 3 page(s) / 31K

Publishing Venue

IBM

Related People

Dominguez, R: AUTHOR [+4]

Abstract

This article describes an interface controlling the use of multiple character generators connected in series in order to combine data from two sources onto a single print simultaneously. The figure shows the serial connection of two character generators 10 and 12 with a printer 17 in a daisy-chain configuration which can interface more than two character generators, if desired. The following description will consider character generator 10 as the downstream device and character generator 12 as the upstream device with an interface consisting of an eight-bit data bus plus parity and control lines to provide an asynchronous DC interlocked control to transfer data onto the data bus. The interface places certain requirements on all of the devices that attach to the bus.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 3

Multiple Character Generators for Data Overlay

This article describes an interface controlling the use of multiple character generators connected in series in order to combine data from two sources onto a single print simultaneously. The figure shows the serial connection of two character generators 10 and 12 with a printer 17 in a daisy-chain configuration which can interface more than two character generators, if desired. The following description will consider character generator 10 as the downstream device and character generator 12 as the upstream device with an interface consisting of an eight-bit data bus plus parity and control lines to provide an asynchronous DC interlocked control to transfer data onto the data bus. The interface places certain requirements on all of the devices that attach to the bus. At the beginning of the normal print, the devices are synchronized with all control lines in the inactive state. When the processor indicates that a start is to commence, the interface allows access to the scan buffer (not shown) so that bytes of data can be fetched by the character generator 10. When the upstream device, character generator 12, is attached to a downstream device, character generator 10, PORTIN line 16 becomes active, indicating the physical connection of both devices.

Otherwise, PORTIN line 16 inactive indicates no physical connection between the devices. In this case, character generator 10 can send data to the printer 17 without regard to the upstream device. But in the case where character generator 12 is attached to character generator 10, the character generator 10 will receive data on the CBIN line 11 and wait for RDYIN line 13 to go active. At this time, the character generator 10 may also have its own byte ready for the printer 17. To combine data, the upstream data from character generator 12 can be ORed with the data from character generator 10. ...