Chapter 3 | Hardware |
Utility Interface
External Power-On Switch
This control signal is provided externally through a switch by connecting ground pin 8 to pin 6 on the Utility connector (J17).
External Reset Switch
This control signal is provided through an external switch by connecting ground pin 12 to pin 10 on the Utility connector.
NOTE To perform the equivalent of a
External Speaker (Beep)
The Beep signals from the I/O Hub (82801FB) and the Super I/O (W83627HF) are fed to pin 13 of the Utility connector through an OR circuit, in conjunction with +5V (pin 7), and drives an external PC Beep speaker. The PC Beep speaker signal from the I/O Hub (Southbridge) is also fed to the
External Power-On LED
This indicator signal is fed to pin 1 and pin 5 of the Utility connector for an external LED to indicate power is applied to the MightyBoard 821.
External IDE Activity LED
This indicator signal is fed to pin 2 and pin 4 of the Utility connector for an external LED to indicate power is applied to the MightyBoard 821.
Table
Pin # | Signal | Description |
1 | PwrLED | |
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| through 330 ohm resistor at pin 1, to ground at pin 5. |
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2, 3 | VCC | + 5 Voltage – Goes to +5 volts through |
4 | IDELED | IDE Activity LED – External IDE Activity LED connection from Primary IDE |
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| channel through Or circuit. Connect external |
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| and pin 4 (IDE_LED). |
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5, 8, 12 | GND | Ground |
6 | PWRSW | |
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| at pin 8. |
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7 | VCC | +5 volts – Provides +5 volts to external device (PC “Beep” speaker). |
9, 11, | NC | Not connected |
14, 15, |
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16 |
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10 | RST | Reset Switch – External Reset switch connection sends reset signal to Super I/O |
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| chip. Connect external Reset Switch between pin 10 and ground, pin 12. |
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13 | SPK | PC Speaker (Beep) – Provides PC beep speaker output to external speaker. Connect |
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| external PC Beep Speaker between pin 7 (+5V) and pin 13. |
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Note: The shaded area denotes power or ground.
24 | Reference Manual | MightyBoard 821 |
