User Manual

Pin Description (Continued)

Name(s)

Number

of Pins

Type Description

INT

10 1 Digital Output Interrupt active low open-drain output. This output is enabled when

Bit 1 in the Configuration Register is set to 1. The default state is

disabled.

DACOut/NTEST_IN 11 1 Analog

Output/Digital

Input

0V to +1.25V amplitude 8-bit DAC output. When forced high by an

external voltage the NAND Tree Test mode is enabled which

provides board-level connectivity testing. Refer to Section 11.0 on

NAND Tree testing.

RESET

12 1 Digital I/O Master Reset, 5 mA driver (open-drain), active low output with a

20 ms minimum pulse width. Available when enabled via Bit 4 in

the Configuration register. It acts as an active low power on

RESET input.

GND 13 1 GROUND Internally connected to all circuitry. The ground reference for all

analog inputs and the DAC output. This pin needs to be

connected to a low noise analog ground plane for optimum

performance of the DAC output.

Vccp2 14 1 Analog Input Analog input for monitoring −12V or Vccp2. Selectable by

choosing the appropriate external resistor divider values such that

the input to the LM81 is scaled to +2.5V. See

Section 4.0.

+12Vin 15 1 Analog Input Analog input for monitoring +12V.

+5Vin 16 1 Analog Input Analog input for monitoring +5V.

+3.3Vin 17 1 Analog Input Analog input for monitoring +3.3V.

+2.5Vin 18 1 Analog Input Analog input for monitoring +2.5V.

Vccp1 19 1 Analog Input Analog input for monitoring Vccp, a processor voltage that is

nominally at +2.5V.

VID4-VID0 20-24 5 Digital Inputs Supply Voltage readouts from the Pentium/PRO power supplies