Browse Prior Art Database

Data Adapter Unit Auto Poll

IP.com Disclosure Number: IPCOM000093936D
Original Publication Date: 1966-Apr-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Murray, RE: AUTHOR [+2]

Abstract

Input/Output terminal control unit circuitry permits a computer channel to select terminals connected to the control unit which are to be polled and to provide autonomous polling by the control unit independent of the channel for negative responsives or timeout. The computer is relieved of interrupts until data is ready for transfer.

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Data Adapter Unit Auto Poll

Input/Output terminal control unit circuitry permits a computer channel to select terminals connected to the control unit which are to be polled and to provide autonomous polling by the control unit independent of the channel for negative responsives or timeout. The computer is relieved of interrupts until data is ready for transfer.

Computer channel 10 provides an initial command signal on line 11 which decoder 12 interprets as a set poll mask command. Such action results in line 14 conditioning And's 15...17. Appropriate levels on lines 18...20 cause mask register 21 to store in address positions 0 to 7 which correspond to the eight I/O terminals connected to the control unit from a common line in this example. A poll command detected by 12 raises line 22. Control logic 25 then initiates automatic polling by indicating on 26 that the I/O terminals are to be placed in the address alert mode.

Counter 27 is then stepped to the first I/O terminal which conditions And 28. Compare 30 determines whether or not this address is masked and, if so, returns a signal to 25 to direct it to step counter 27 to the next address position. If 30 indicated that I/O terminal 0 address is not masked, gate counter 31, by circuitry, not shown, is initiated to sequentially gate the terminal address through And's
32... 34 to output line 35 and thus to the I/O terminals provided 25 has conditioned 32...34. After the address is gated out, 25 indicates on line 3...