JP3677256B2 - Expansion card mounting recognition device, expansion card and expansion card mounting detection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an expansion card mounting recognition device, an expansion card, and an expansion card mounting detection method applied to a computer system.
[0002]
[Prior art]
In a computer system in which a PCI card can be mounted in a card slot (PCI slot) of a motherboard, conventionally, a card detection pull-up resistor (resistance value) provided on the motherboard has been fixed.
[0003]
Explaining with a specific example, whether or not a PCI card is mounted in the PCI slot according to whether or not the voltage of the PRSNT signal pin of the PCI slot provided on the motherboard of the computer is a certain level of voltage. Judging. At this time, if a pull-up resistor is provided on the PCI slot side of the motherboard of the computer, a pull-down resistor is provided on the PCI card side, and a PCI card is mounted in the PCI slot, the pull-up resistor provided on the PCI slot side of the motherboard is provided. A resistor and a pull-down resistor provided on the PCI card side are connected via a connector, and the voltage at the connection point becomes a PRSNT signal for determining whether or not the PCI card is mounted.
[0004]
That is, the voltage obtained by dividing the operating power supply VCC of the motherboard by the pull-up resistor and the pull-down resistor is the PRSNT signal. When this PRSNT signal is at the active low level (for example, 0.8 V or less), the PCI slot It is recognized that a PCI card is installed.
[0005]
Here, conventionally, the pull-down resistor of the PCI card is a preset fixed resistance value unique to the card. Therefore, for a PCI card having a different resistance value of the pull-down resistor, the PCI card is connected to the PCI of the motherboard. Even if it is mounted in the slot, the PRSNT signal for recognizing the PCI card does not become an active LOW level, and there is a problem that the mounting state of the PCI card cannot be recognized.
[0006]
[Problems to be solved by the invention]
As described above, conventionally, for a PCI card having a different resistance value of the pull-down resistor, even if the PCI card is mounted in the PCI slot of the motherboard, the PRSNT signal for recognizing the PCI card does not become the active LOW level. There was a problem that the mounting state of the card could not be recognized. Accordingly, a PCI card that can be used by being mounted in the PCI card slot is limited to a PCI card having a pull-down resistor having a predetermined resistance value, and a PCI card having a pull-down resistor having a resistance value different from that of the PCI card cannot be used. There was a problem.
[0007]
The present invention has been made in view of the above circumstances, and provides an expansion card mounting recognition device, an expansion card, and an expansion card mounting detection method that can reliably recognize the mounting state of the expansion card on the motherboard side of the computer. For the purpose.
[0008]
[Means for Solving the Problems]
The present invention includes means for automatically setting a pull-down resistance value on the card side so that when the expansion card is mounted in the card slot of the motherboard, the motherboard becomes a signal bell that can detect the mounting state. It is characterized by that .
That is, the present invention includes a pull-up resistor for card detection provided on the motherboard, the potential of the connection point between the pull-down resistor provided on the expansion card mounted on the card slot of the motherboard circuit provided on the mother board In the expansion card mounting recognition apparatus that recognizes the mounting state of the expansion card, the expansion card includes a plurality of pull-down resistors having different resistance values, and selects one pull-down resistor from the plurality of pull-down resistors. A resistor selector connected to the pull-up resistor, and the potential of the connection point is detected, and when the potential of the connection point does not reach a card detection level at which a circuit mounted on the motherboard can recognize card mounting and a controller for a resistance selector control to switch the pull-down resistor connected to the pull-up resistor Characterized in that was.
[0009]
Further, the present invention includes a pull-up resistor for card detection provided on the motherboard, the potential of the connection point between the pull-down resistor provided on the expansion card mounted on the card slot of the motherboard circuit provided on the mother board In the expansion card mounting recognition apparatus for recognizing the mounting state of the expansion card, the expansion card has a plurality of pull-down resistors, one of the pull-down resistors is connected to the pull-up resistor, and the connection When the potential at the point is not at the card detection level at which the circuit mounted on the motherboard can recognize the card mounting, the pull-down resistors are connected in parallel one by one until the potential at the connection point reaches the card detection level. A circuit is provided.
Further, according to the present invention, a circuit provided on the motherboard has a potential of a connection point between a pull-up resistor for card detection provided on the motherboard and a pull-down resistor provided on an expansion card mounted on the card slot of the motherboard. In the expansion card mounting recognition device for recognizing the mounting state of the expansion card,
When the expansion card is connected to a plurality of pull-down resistors connected in series to the pull-up resistor, and the potential of the connection point is not at a card detection level that can recognize the mounting of the card in a circuit mounted on the motherboard, the connection A circuit is provided in which the pull-down resistors are short-circuited one by one until the potential at the point reaches the card detection level .
[0010]
Further, the present invention relates to an expansion card having a pull-down resistor mounted on a card slot provided on a motherboard of a computer and connected to a pull-up resistor for detecting an expansion card provided on the motherboard at the time of mounting. The resistance value of the pull-down resistor connected to the pull-up resistor when the potential at the connection point between the pull-up resistor and the pull-down resistor does not reach the card detection level at which the circuit mounted on the motherboard can recognize the card mounting. A circuit for switching between is provided.
[0011]
Further, the present invention provides an expansion card mounting detection method in which the motherboard detects mounting of an expansion card by a connection point potential between a pull-up resistor provided on the motherboard and a pull-down resistor provided on the expansion card. When the expansion card is mounted on the motherboard, the resistance value of the pull-down resistor is controlled on the expansion card side so that the connection point potential becomes the expansion card detection level on the motherboard side.
[0012]
As described above, the expansion card mounted in the card slot of the motherboard has a pull-down resistor setting mechanism, so that when the expansion card is mounted in the card slot of the motherboard, the motherboard, for example, pull-down resistance of other cards Even if the card detection mechanism is adapted to the above, the mounting state of each card can be reliably recognized.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
First, the configuration and operation in the first embodiment of the present invention will be described with reference to FIGS.
[0015]
FIG. 1 is a block diagram showing a configuration of a main part in the first embodiment of the present invention, and FIG. 2 is a circuit configuration diagram showing a configuration of the resistor selector 22 shown in FIG. FIG. 3 is a flowchart showing a processing procedure of the controller 21 shown in FIG.
[0016]
In FIG. 1, reference numeral 10 denotes a computer motherboard. Reference numeral 20 denotes an expansion card (PCI card) mounted in the card slot of the motherboard 10 and connected to the PCI bus of the motherboard 10. Reference numeral 30 denotes an expansion connector (PCI connector) provided in a card slot of the mother board 10 for circuit connection between the mother board 10 and the PCI card 20.
[0017]
On the motherboard 10, a card detection pull-up resistor R <b> 1 is provided between the operating power supply line (Vcc line) of the motherboard 10 and the PRSNT pin 31 of the PCI connector 30. In addition, a circuit for determining the mounting state of the PCI card 20 by using the signal of the PRSNT pin 31 as a card detection signal NA, a PCI bus (none of which is not shown) and the like to which the PCI card 20 is connected are provided.
[0018]
The PCI card 20 is provided with a controller 21 that performs pull-down resistance selection control as shown in FIG. 3 and a resistance selector 22 configured as shown in FIG.
[0019]
The controller 21 receives a PRSNT signal output from the PRSNT pin 31 of the PCI connector 30 when the PCI card 20 is mounted in the card slot of the motherboard 10. Then, the controller 21 executes processing as shown in FIG. 3, decodes the voltage of the PRSNT signal, and selects one resistor (Ra / Rb / Rc) from the resistor selector 22 whose circuit configuration is shown in FIG. I do.
[0020]
As shown in FIG. 2, the resistor selector 22 selects, for example, three resistors Ra, Rb, and Rc having different resistance values, and selects one resistor from the resistors Ra, Rb, and Rc, and supplies the selected resistor to the PRSNT pin 31. And a switch circuit 23 to be connected. The switch circuit 23 receives the decoded output from the controller 21, selects one resistor from the three resistors Ra, Rb, and Rc prepared in advance, and uses this resistor as a pull-down resistor to connect to the PRSNT pin 31 and the ground. It is inserted between the line (GND line).
[0021]
Here, of the three resistors Ra, Rb, and Rc, the resistance value of the resistor Ra is the largest and the resistance value of the resistor Rc is the smallest (Ra>Rb> Rc). When the PCI card 20 is mounted in the card slot of the motherboard 10 and the PCI card 20 is connected to the motherboard 10 via the PCI connector 30, the controller 21 first sets the resistor Ra having the largest resistance value. Selected.
[0022]
Here, the operation in the first embodiment of the present invention will be described with reference to FIGS.
[0023]
When the PCI card 20 is mounted in the card slot of the motherboard 10 and the PCI card 20 is circuit-connected to the motherboard 10 via the PCI connector 30, the controller 21 provided in the PCI card 20 performs the processing shown in FIG. The switch circuit 23 of the resistor selector 22 is automatically set based on the instruction to select a pull-down resistor that matches the card detection level of 10.
[0024]
That is, when the PCI card 20 is connected to the motherboard 10 via the PCI connector 30, the controller 21 first selects the resistor Ra having the largest resistance value for the switch circuit 23 of the resistor selector 22. An instruction is given (step S1 in FIG. 3). As a result, the resistor Ra is connected as a pull-down resistor between the PRSNT pin 31 of the PCI connector 30 and the GND line. As a result, the PRSNT signal output to the PRSNT pin 31 of the PCI connector 30 to which the resistor Ra is connected is input to the controller 21. The controller 21 decodes the voltage indicated by the PRSNT signal, and determines whether or not the voltage at the PRSNT pin 31 is an active low level at which card detection is possible on the motherboard 10 (step S2 in FIG. 3).
[0025]
Here, when the voltage of the PRSNT pin 31 is at an active low level at which the mother board 10 can detect the card, the processing ends there. If the voltage at the PRSNT pin 31 is not an active low level at which the motherboard 10 can detect the card, the controller 21 next instructs the switch circuit 23 of the resistor selector 22 to select the resistor Rb ( Similarly, it is determined whether or not the voltage of the PRSNT pin 31 at that time is an active low level at which the card can be detected by the mother board 10 (step S4 in FIG. 3).
[0026]
Here, when the voltage of the PRSNT pin 31 is at an active low level at which the mother board 10 can detect the card, the processing ends there. If the voltage of the PRSNT pin 31 is not an active low level at which the motherboard 10 can detect the card, the controller 21 next instructs the switch circuit 23 of the resistor selector 22 to select the resistor Rc ( In FIG. 3 step S5), the process is terminated.
[0027]
Thus, when the PCI card 20 is mounted in the card slot of the motherboard 10, the controller 21 provided in the PCI card 20 sets the voltage of the PRSNT pin 31 to the active low level at which the motherboard 10 can detect the card. Control to be.
[0028]
As a result, when the PCI card 20 is mounted in the card slot of the mother board 10, even if the mother board 10 remains in the card detection mechanism that matches the pull-down resistance of other cards, the mounting state of each card is surely ensured. Can be recognized.
[0029]
FIG. 4 shows a second embodiment of the present invention. The same parts as those in the first embodiment shown in FIG. 1 and FIG.
[0030]
The second embodiment is particularly different from the first embodiment described above in that the controller 21 enables only the decode output Dout0 at the initial stage, switches on only the switching gate SG1, and pulls down only the resistor Ra. A resistor is connected between the PRSNT pin 31 and the GND line.
[0031]
Here, it is determined whether or not the voltage of the PRSNT pin 31 is an active low level at which the card can be detected by the motherboard 10, and the voltage of the PRSNT pin 31 must be at an active low level at which the card can be detected by the motherboard 10. Next, in addition to the decode output Dout0, the decode output Dout1 is enabled, the switch gate SG2 is switched on in addition to the switching gate SG1, and a pull-down resistor in which the resistor Ra and the resistor Rb are connected in parallel is connected to the PRSNT pin 31. And the GND line.
[0032]
Here, if the voltage of the PRSNT pin 31 is not an active low level at which the card detection is possible in the motherboard 10, the decode output Dout2 is enabled in addition to the decode outputs Dout0 and Dout1, and the switching gate SG1, In addition to SG2, the switching gate SG3 is switched on, and a pull-down resistor having resistors Ra, Rb, and Rc connected in parallel is connected between the PRSNT pin 31 and the GND line.
[0033]
In this manner, in the second embodiment, the resistors Ra, Rb, and Rc are connected in parallel one by one until the voltage of the PRSNT pin 31 becomes an active low level at which the motherboard 10 can detect the card.
[0034]
Also in the configuration of the second embodiment as described above, when the PCI card 20 is mounted in the card slot of the motherboard 10 as in the first embodiment described above, the motherboard 10 may be connected to other cards. Even if the card detection mechanism is matched to the pull-down resistor, the mounting state of each card can be reliably recognized.
[0035]
FIG. 5 shows a third embodiment of the present invention. The same reference numerals are given to the same parts as those of the first embodiment shown in FIGS. 1 and 2 and the description thereof is omitted.
[0036]
The third embodiment differs from the second embodiment described above in that the second embodiment described above has three decode outputs Dout0, Dout1, Dout2 and three switching gates SG1, SG2, SG3. In contrast to the configuration used, in the third embodiment, functions similar to those in the first and second embodiments described above using two decode outputs Douta and Doutb and two switching gates SG1 and SG2 are used. Is realized.
[0037]
FIG. 6 shows a fourth embodiment of the present invention. The same parts as those in the first embodiment shown in FIG. 1 and FIG.
[0038]
The fourth embodiment differs from the second and third embodiments described above in that the second and third embodiments connect resistors Ra, Rb, and Rc in parallel one by one. In contrast to this configuration, in the fourth embodiment, resistors Ra, Rb, and Rc are connected in series, one end thereof is connected to the PRSNT pin 31, the other end is connected to the GND line, and the PRSNT pin is connected. The resistors are short-circuited one by one using the switching gates SG1 and SG2 until the voltage of 31 reaches an active low level at which the mother board 10 can detect the card.
[0039]
Also in the configuration of the fourth embodiment as described above, when the PCI card 20 is mounted in the card slot of the mother board 10 as in the first to third embodiments, the mother board 10 may be replaced with the other. Even if the card detection mechanism matches the pull-down resistance of the card, the mounting state of each card can be recognized with certainty.
[0040]
【The invention's effect】
As described above in detail, according to the present invention, the expansion card mounted in the card slot of the motherboard has a pull-down resistor setting mechanism, so that when the expansion card is mounted in the card slot of the motherboard, Even if the card detection mechanism is adjusted to the pull-down resistance of another card, the mounting state of each card can be reliably recognized.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a main part in a first embodiment of the present invention.
FIG. 2 is a circuit configuration diagram showing a configuration of a resistance selector in the embodiment.
FIG. 3 is a flowchart showing a processing procedure of a controller 21 in the embodiment.
FIG. 4 is a diagram showing a circuit configuration of a main part of a PCI card according to a second embodiment of the present invention.
FIG. 5 is a diagram showing a circuit configuration of a main part of a PCI card according to a third embodiment of the present invention.
FIG. 6 is a diagram showing a circuit configuration of a main part of a PCI card according to a fourth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Mother board 20 ... PCI card 21 ... Controller 22 ... Resistance selector 23 ... Switch circuit 30 ... PCI connector 31 ... PRSNT pin R1 ... Pull-up resistance Ra, Rb, Rc ... Resistance (pull-down resistance)
SG1, SG2, SG3 ... Switching gate

Claims (5)

The circuit provided on the motherboard is mounted on the expansion card by the potential at the connection point between the pull-up resistor for card detection provided on the motherboard and the pull-down resistor provided on the expansion card mounted on the card slot of the motherboard. In the expansion card mounting recognition device that recognizes
In the expansion card,
A plurality of pull-down resistors having different resistance values, a resistor selector that selects one pull-down resistor from the plurality of pull-down resistors and connects to the pull-up resistor;
The potential of the connection point is detected, and when the potential of the connection point has not reached a card detection level at which a card mounted can be recognized by a circuit mounted on the motherboard, the resistance selector is controlled and connected to the pull-up resistor An expansion card mounting recognition apparatus, comprising: a controller that switches a pull-down resistor to be connected. A pull-up resistor for card detection provided on the motherboard, the potential of the connection point between the pull-down resistor provided on the expansion card mounted on the card slot of the motherboard mounted state of the circuit provided in the motherboard the expansion card In the expansion card mounting recognition device that recognizes
In the expansion card,
When there is a plurality of pull-down resistors, one of the pull-down resistors is connected to the pull-up resistor, and the potential at the connection point is not at a card detection level at which the circuit mounted on the motherboard can recognize the card mounting An expansion card mounting recognition apparatus comprising a circuit for connecting the pull-down resistors in parallel one by one until the potential at the connection point reaches the card detection level . The circuit provided on the motherboard is mounted on the expansion card by the potential at the connection point between the pull-up resistor for card detection provided on the motherboard and the pull-down resistor provided on the expansion card mounted on the card slot of the motherboard. In the expansion card mounting recognition device that recognizes
In the expansion card,
When a plurality of pull-down resistors connected in series are connected to the pull-up resistor, and the potential at the connection point is not at a card detection level at which a circuit mounted on the motherboard can recognize card mounting, the potential at the connection point is An expansion card mounting recognition apparatus comprising a circuit for short-circuiting the pull-down resistors one by one until a card detection level is reached . In an expansion card having a pull-down resistor that is mounted on a card slot provided on a motherboard of a computer and connected to a pull-up resistor for detecting an expansion card provided on the motherboard when mounted.
The resistance of the pull-down resistor connected to the pull-up resistor when the potential of the connection point between the pull-up resistor and the pull-down resistor does not reach the card detection level at which the circuit mounted on the motherboard can recognize the card mounting. An expansion card provided with a circuit for switching values . In the expansion card mounting detection method in which the motherboard detects the mounting of the expansion card by the connection point potential between the pull-up resistor provided on the motherboard and the pull-down resistor provided on the expansion card.
  An expansion card, wherein when the expansion card is mounted on the motherboard, a resistance value of a pull-down resistor is controlled on the expansion card side so that the connection point potential becomes an expansion card detection level on the motherboard side. Implementation detection method.

Images