Tester with driver/sensor circuit having programmable termination devices
First Claim
1. A tester for testing printed circuit boards, said tester comprising in combination:
- (a) a processor;
(b) a bus connected to said processor;
(c) a plurality of programmable driver/sensor circuits each having a data input terminal and a terminal selectively programmable either as an input terminal for sensing a signal on said programmable terminal or as an output terminal responsive to a data signal applied to said data input terminal;
(d) first means for coupling said programmable terminals to the respective terminals of a printed circuit board to be tested;
(e) second means responsive to said processor for routing information from said bus to the data input terminals of said driver/sensor circuit; and
(f) each of said driver/sensor circuits further comprising first and second termination means for producing pull-up and pull-down currents coupled to the programmable terminal of that driver/sensor circuit; and
(g) mode control means for selecting said first or said second termination means for producing said pull-up or said pull-down current coupled to the programmable terminal of said driver/sensor circuit.
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Accused Products
Abstract
Portable tester and method for testing a variety of printed circuit boards without utilizing specialized adaptor boards for rerouting input test signals and supply voltages from the tester to various pins of the board under test. A plurality of edge connectors have their respective pins connected to corresponding edge connector stake pins. Each edge connector stake pin is connected to or isolated from the corresponding driver/sensor stake pin by means of a switch. Each driver/sensor stake pin is connected to the input/output terminal of a programmable driver/sensor circuit. A main processor is utilized to store a test program and to transmit data and control information to predetermined driver/sensor circuits. A high speed processor coupled between the main processor and the inputs of the driver/sensor circuits includes a parallel-loadable shift register, an instruction register, an instruction decoder and control circuitry connected to the inputs of the driver/sensor circuitry. The high speed processor memory can store a bus-defining subroutine containing a sequence of data shifting instructions which shift a word in the shift register to the input of driver/sensor circuits specified by the arguments of the shifting instruction at high speed, thereby achieving high speed routing of data from the main processor to the board under test with very few instructions of the test program. Each driver/sensor circuit has programmable pull-up and pull-down termination devices which obviate the need for certain termination resistors on the board under test.
72 Citations
6 Claims
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1. A tester for testing printed circuit boards, said tester comprising in combination:
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(a) a processor; (b) a bus connected to said processor; (c) a plurality of programmable driver/sensor circuits each having a data input terminal and a terminal selectively programmable either as an input terminal for sensing a signal on said programmable terminal or as an output terminal responsive to a data signal applied to said data input terminal; (d) first means for coupling said programmable terminals to the respective terminals of a printed circuit board to be tested; (e) second means responsive to said processor for routing information from said bus to the data input terminals of said driver/sensor circuit; and (f) each of said driver/sensor circuits further comprising first and second termination means for producing pull-up and pull-down currents coupled to the programmable terminal of that driver/sensor circuit; and (g) mode control means for selecting said first or said second termination means for producing said pull-up or said pull-down current coupled to the programmable terminal of said driver/sensor circuit.
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2. A tester for testing printed circuit boards, said tester comprising in combination:
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(a) a processor; (b) a bus connected to said processor; (c) a plurality of programmable driver/sensor circuits each having a data input terminal and a terminal selectively programmable either as an input terminal for sensing a signal on said programmable terminal or as an output terminal responsive to a data signal applied to said data input terminal; (d) first means for coupling said programmable terminals to the respective terminals of a printed circuit board to be tested; (e) second means responsive to said processor for routing information from said bus to the data input terminals of said driver/sensor circuit; (f) each of said driver/sensor circuits further comprising first termination means programmable for producing a pull-up current flowing into the programmable terminal of that driver/sensor circuit, whereby pull-up termination devices may be omitted from said printed circuit boards; (g) each of said driver/sensor circuits further comprising second termination means programmable for producing a pull-down current flowing out of the programmable terminal of that driver/sensor circuit, whereby pull-down termination devices may be omitted from said printed circuit boards; (h) wherein said first and second termination means include first and second current sources, respectively, for producing said pull-up and pull-down currents, respectively; (i) wherein each of said driver/sensor circuits includes a plurality of mode control inputs and mode control means responsive to said mode control inputs for controlling the programmable functions of said driver/sensor circuits; and (j) wherein each of said driver/sensor circuits further includes sensing circuit means responsive to said programmable terminal and said mode control means for sensing a signal applied to said programmable terminal and turning off said pull-up current and said pull-down current when said mode control inputs are in a first configuration. - View Dependent Claims (3, 4, 5)
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6. A programmable driver/sensor circuit suitable for use in a processor-oriented tester, said driver/sensor circuit comprising in combination:
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(a) a data input terminal and a terminal selectively programmable either as an input terminal for sensing a signal on said programmable terminal or as an output terminal responsive to a data signal applied to said data input terminal; (b) first and second termination means for producing pull-up and pull-down currents coupled to the programmable terminal of that driver/sensor circuit; and (c) mode control means for selecting said first or said second termination means for producing said pull-up or said pull-down current coupled to the programmable terminal of said driver/sensor circuit.
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Specification