Author Topic: Digital Outputs on the PCI & PCIe PC WATCHDOG DB-25 Connector  (Read 3069 times)

Admin

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Digital Outputs on the PCI & PCIe PC WATCHDOG DB-25 Connector
« on: September 13, 2010, 15:36:19 »
The PCI and PCIe boards have 4 general purpose digital output pins on the 25 pin DSub connector. These are not used by the PCI PC Watchdog and are available to the user for exclusive control from their application program using the DLL API library.

We are often asked about the electrical characteristics of these outputs. They are driven by a 74LVC06 open-drain driver IC:
  http://focus.ti.com/docs/prod/folders/print/sn74lvc06a.html
with 1.0K pull-up resistors connected to +5.0V.

When the PCI PC Watchdog powers up, the values in the digital output registers are set to zero (0). The 74LVC06 inverts the zero or low level on its input so that the open-drain output is off or high impedance. The pull-up resistor causes the output to float high or at +5.0V. When you write a one (1) to the digital output register the 74LVC06 turns on the open-drain output and makes a low impedance path to ground (0.0V).

When the 74LVC06 open-drain is active it can sink a max of 19mA at a max of +5.0V. This may be enough to turn on an external small relay if you make sure to include a back EMF diode to protect the output of the 74LVC06.
« Last Edit: September 13, 2010, 17:10:01 by Admin »

meirdkl

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Re: Digital Outputs on the PCI & PCIe PC WATCHDOG DB-25 Connector
« Reply #1 on: November 11, 2010, 12:39:06 »
does this pci 1130/1134 support win2k3 server?
which program should i use to program the card for getting input of external temp. sensor

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Re: Digital Outputs on the PCI & PCIe PC WATCHDOG DB-25 Connector
« Reply #2 on: November 11, 2010, 17:26:22 »
The board will work with Win2K server. There are some notes on the CD about migrating from SP1 or SP2 to SP3.

There are no programs for reading an external temp sensor. There is an 8 bit A/D input on the DB-25 where you could connect an analog sensor. You would have write a little software to read the value and determine what action to take. There is a a function in the supplied DLL that you can call from a Console AP or a .NET app that will return the A/D value.

A sensor like the Analog Devices TMP37 or the National Semi LM35 would work for the temp sensor. They can be powered by the +5V and GND on the DB-25 and their analog output voltage connected to the A/D input on the DB-25.