Patent EP0501489A1 successfully refreshed from Google Patents.
EP0501489A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Advanced functionality parallel port interface
Assignee: HP Inc
•
Filing: 1992-02-27
•
Granted: —
•
Expires: 2012-02-27
Abstract
Abstract A peripheral unit (10) and computer (14) are connected by an existing communication link (12) which provides a plurality of unidirectional bit and command lines (40, 42, 44, 46) from the computer (14) to the peripheral unit (10) and a plurality of unidirectional, status lines (48, 50, 52, 54, 56) from the peripheral unit (10) to the computer (14). The peripheral unit (10) has an advanced functionality which enables transfer over its outgoing status lines (48, 50, 52, 54,56) of added peripheral unit data. The computer (14) emplaces inconsistent logic states on at least a pair of command lines (44, 46) to the peripheral unit (10) to inquire whether the peripheral unit (10) contains the advanced functionality capability. The peripheral unit (10) responds by transmitting an acknowledgement over at least one of its outgoing status lines (48) that it possesses the capability. The computer (14) then polls the peripheral unit's (10) status lines (48, 50) to determine the presence of the acknowledgement and, absent the sampling action, is unaware of the acknowledgement. The computer (14), subsequent to the acknowledgement, determines if added peripheral unit status data is indicated (52) as awaiting transfer, and if so, sets a command line (44) to request the added peripheral unit (10) status data. The peripheral unit (10) then places the data onto a status line (50) for transit to the computer (14), thereby enabling the preexisting communication link (12) to handle the added data.
Inventors
- 👤 Eric L. Bokman
- 👤 Michael J. Ryan
- 👤 Michael D. Dobbs
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 19:39
CPC Classifications
G; G06; G06F; G06F13/00; G06F13/38; G06F13/42; G06F13/4204; G06F13/4221; G06F13/4226; G06F3/00; G06F3/12; G06F3/1201; G06F3/1202; G06F3/1203; G06F3/1207; G06F3/1223; G06F3/1229; G06F3/1278; G06F3/1284; G06F2213/00; G06F2213/0004
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
193 words
A peripheral system (10) adapted for interconnection to a computer (14), said peripheral system including a communication link that interconnects to a plurality of incoming lines (40, 42, 44, 46) from said computer (14), said lines providing both data bits and command levels, said communication link also having a plurality of outgoing lines (48, 50, 52, 54, 56) that provide levels indicative of status of said peripheral system (10), said peripheral system (10) including advanced functional means for enabling said outgoing lines (48, 50, 52, 54, 56) to transmit added peripheral system data, said means comprising: processor means (16) for recognizing as a signal, inconsistent command level logic states on at least a pair (44, 46) of said incoming lines (40, 42, 44, 46) , and for transmitting an acknowledgement of said signal to said computer; and means (30) for transferring to said computer (14) over at least one outgoing status line (50), data bits indicative of said added peripheral system data, said means (30) for transferring actuated upon receipt by said peripheral system (10) of a predetermined command level on at least one of said incoming lines (44) from said computer (14).
Claim 2
Dependent Claim
37 words
The peripheral system as recited in claim 1, wherein said peripheral system (10) acknowledgement is manifested by an inversion of levels on at least a pair (48, 50) of said outgoing lines (48, 50, 52, 54, 56).
Claim 3
Dependent Claim
26 words
The peripheral system as recited in claim 2, wherein said acknowledgement indicates to said computer (14) that said peripheral system (10) includes said advanced functional means.
Claim 4
Dependent Claim
53 words
The peripheral system as recited in claim 3, wherein said processor means (16) includes additional means for setting a level on an outgoing status line (52) after said acknowledgement is transmitted and said predetermined command level is received from said computer (14), said set level indicating the availability of added peripheral system data.
Claim 5
Dependent Claim
62 words
The peripheral system as recited in claim 4, wherein said predetermined command level is only present on said input line (44) for the duration of a transfer of a byte of data bits, said processor means (16) responding to a subsequent absence of said predetermined command level to reset all outgoing lines (48, 50, 52, 54, 56) to manifest default status levels.
Claim 6
Dependent Claim
245 words
A peripheral (10) for interconnection to a computer (14), said peripheral (10) including circuitry and software and implementing a parallel interface, i.e. a "Centronics" interface, said circuitry including an interface connection (12) for accommodating a plurality of lines, a first set of said lines (40, 42, 44, 46) allocated to handling incoming bit states for parallel bit data and a plurality of command states from the computer (14), said command states including at least Strobe, SelIn and AutoFd command levels and a second set of lines (48, 50, 52, 54, 56), outgoing from said printer, allocated to indicate status levels for Fault, PError, Select, Ack and Busy designations, said peripheral (10) including advanced functionality means for providing detailed status information to said computer (14) over said outgoing lines (48, 50, 52, 54, 56) in addition to said status designations, the peripheral comprising: means (16, 28) for responding to inconsistent logic states on a pair (44, 46) of incoming command lines from said computer (14), by inverting levels on a pair (48, 50) of said outgoing status lines, to signal the presence on said peripheral (10) of said advanced functionality means; means (16, 30) for impressing a status level on an outgoing status line (52) to indicate the availability for output, of said detailed status information; and means responsive to a command level received on a said incoming command line (44) to impress bit values on a said status line (50) for transmission to said computer.
Claim 7
Dependent Claim
23 words
The peripheral as recited in claim 6, wherein said bit values are transmitted serially to said computer (14) over said status line (50).
Claim 8
Dependent Claim
57 words
The peripheral as recited in claim 7, wherein said computer (14) removes said command levels from said incoming command lines after a byte of data bits have been serially received by said computer, and said advanced functionality means includes further means (16) for responding thereto by resetting all levels on said outgoing status lines to default values.
Claim 9
Dependent Claim
26 words
The peripheral as recited in claim 8, wherein said inconsistent logic states are received from said computer (14) over said SelIn and AutoFd lines (44, 46).
Claim 10
Dependent Claim
28 words
The peripheral as recited in claim 9, wherein said means for responding to said inconsistent logic status inverts levels on said Fault and PError outgoing lines (48, 50).
Claim 11
Dependent Claim
23 words
The peripheral as recited in claim 10, wherein said means for impressing a status level places said level on said Select line (52).
Claim 12
Dependent Claim
31 words
The peripheral as recited in claim 11, wherein said responsive means senses an incoming command level on said SelIn line (44) and impresses bit values on the outgoing PError line (50).
Claim 13
Independent Claim
271 words
A system comprising a computer (14) and a peripheral unit (10), said computer (14) and peripheral unit (10) connected via an existing communication link (12) that includes a plurality of unidirectional bit lines and command lines (40, 42, 44, 46) from the computer (14) to the peripheral unit (10), and a plurality of unidirectional status lines (48, 50, 52, 54, 56) from the peripheral unit (10) to the computer (14), said peripheral unit (10) including advanced functional means for enabling transfer over said status lines of added peripheral unit data, the system comprising: means in said computer for emplacing inconsistent logic states on at least a pair of said command lines (44, 46); means (28, 16, 30) in said peripheral unit (10) responsive to said inconsistent logic states for transmitting an acknowledgement over at least a first status line (48), said acknowledgement indicating that said peripheral unit (10) includes said advanced functional means; polling means in said computer (14) for sampling at least said first status line (48) to determine the presence of said acknowledgement, said computer (14), in the absence of said sampling, being unaware of said acknowledgement, said polling means responsive to said acknowledgement to further determine by sensing the level on a status line (52) if added peripheral unit data is present for transfer in said peripheral unit (10) and, if so, issuing a level on a command line (44) to request said added peripheral unit data; and means (30) in said peripheral unit for responding to said level on said command line for impressing added peripheral unit data on a status line for transmission to said computer.
Claim 14
Dependent Claim
35 words
The system as recited in claim 13, wherein said polling means activates said sampling of said status line (48) automatically after said computer (14) emplaces said inconsistent logic states on said command lines (44, 46).
Claim 15
Dependent Claim
24 words
The system as recited in claim 14 wherein said acknowledgement is manifest by reversal of levels on at least two status lines (48, 50).
Claim 16
Dependent Claim
25 words
The system as recited in claim 15, wherein said poling means terminates said sampling action if an acknowledgement is not received within a predetermined time.
Claim 17
Dependent Claim
73 words
The system as recited in claim 16 wherein said peripheral unit means for responding (30) applies said added peripheral unit data on a serial-by-bit basis on said status line (50), said computer (14) terminating said data transfer after a byte of said data has been received, said emplacing means in said computer (14) being again activated to provide said inconsistent logic states and to commence transfer of a new byte of data thereafter.
Claim 18
Dependent Claim
47 words
The system as recited in claim 17 wherein said computer (14) includes default communication means for transmitting to said peripheral unit a query concerning said added peripheral unit data, whereby said peripheral unit (10) responds by loading said added peripheral unit data in an output register (30).
Claim 19
Dependent Claim
246 words
In a system comprising a computer (14) and a peripheral unit (10) connected via an existing communication link (12) that provides a plurality of unidirectional bit and command lines (40, 42, 44, 46) from the computer (14) to the peripheral unit (10), and a plurality of unidirectional status lines (48, 50, 52, 54, 56) from the peripheral unit (10) to the computer (14), said peripheral unit (10) including advanced functional means for transferring over a said status line (50), added peripheral unit data, the method comprising: (a) controlling said computer (14) to emplace inconsistent logic states on at least a pair of said command lines (44, 46), said inconsistent logic states in effect, inquiring whether said peripheral unit (10) implements said advanced functional means; (b) operating said peripheral unit (10) to respond to said inconsistent logic states by transmitting an acknowledgement over at least a first status line (48) indicating that it does implement said advanced functional means; (c) controlling said computer (14) to sample at least a said first status line (48) to determine the presence of said acknowledgement, and upon sensing the presence of said acknowledgement, sampling a status line (52) from said peripheral unit to determine if said added peripheral unit data is available and, if so, transmitting a command (44) to said peripheral unit to provide said added peripheral unit data; and (d) controlling said peripheral unit to transmit said added data on a selected status line (50) to said computer (14).
Claim 20
Dependent Claim
50 words
The method as recited in claim 19, wherein said step (b) transmits said acknowledgement by reversing levels on said first status line (48) and a second status line (50), and in said step (c), said computer sampling said first and second status lines (48, 50) to sense said revised levels.
Claim 21
Dependent Claim
22 words
The method as recited in claim 20, wherein said step (d) causes said peripheral unit (10) to transmit said added data serial-by-bit.
Claim 22
Dependent Claim
38 words
The method as recited in claim 21, further comprising the added step of: (e) terminating said transmission of said added data after a byte thereof has been transferred, and causing said method to recycle to step (a) thereafter.
Claim 23
Dependent Claim
182 words
In a peripheral system (10) adapted for interconnection to a computer (14), said peripheral system (10) provided with an existing communication link (14) that interconnects to a plurality of incoming command and data bit lines (40, 42, 44, 46) from said computer (14), said communication link (12) also having a plurality of outgoing status lines (48, 50, 52, 54, 56) from said peripheral system (10) to said computer (14), said peripheral system (10) including advanced functional means for enabling said outgoing lines to transmit added peripheral system (10) data, said peripheral system performing the method of: recognizing inconsistent command level logic states on at least a pair of said incoming command lines (44, 46) as a signal for said peripheral unit (10) to indicate whether it implements said advanced functional means, an acknowledgement indicating said implementation; transmitting an acknowledgement (52) to said computer; and responding to a received predetermined command level from said computer (14) over a command line (52) by transferring to said computer over at least one outgoing status line (50), data bits indicative of said added peripheral system data.
Claim 24
Dependent Claim
30 words
The method as recited in claim 23 wherein said peripheral unit (10) provides said acknowledgement by inverting levels on at least a pair of said outgoing status lines (48, 50).
Claim 25
Dependent Claim
36 words
The method as recited in claim 24 wherein said peripheral unit, subsequent to said acknowledgement, sets a level on a said outgoing status line (52) indicating the availability of said added peripheral unit data for output.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.