Rainbow Electronics LM93 - Manual (Page 8)

9.0 Pin Descriptions
Symbol Pin # Type Function
GPIO_0/TACH1 1 Digital I/O
(Open-Drain)
Can be configured as fan tach input or a general purpose
open-drain digital I/O.
GPIO_1/TACH2 2 Digital I/O
(Open-Drain)
Can be configured as fan tach input or a general purpose
open-drain digital I/O.
GPIO_2/TACH3 3 Digital I/O
(Open-Drain)
Can be configured as fan tach input or a general purpose
open-drain digital I/O.
GPIO_3/TACH4 4 Digital I/O
(Open-Drain)
Can be configured as fan tach input or a general purpose
open-drain digital I/O..
GPIO_4 /
P1_THERMTRIP
5 Digital I/O
(Open-Drain)
A general purpose open-drain digital I/O. Can be configured to
monitor a CPU’s THERMTRIP signal to mask other errors.
GPIO_5 /
P2_THERMTRIP
6 Digital I/O
(Open-Drain)
A general purpose open-drain digital I/O. Can be configured to
monitor a CPU’s THERMTRIP signal to mask other errors.
GPIO_6 7 Digital I/O
(Open-Drain)
Can be used to detect the state of CPU1 IERR or a general purpose
open-drain digital I/O
GPIO_7 8 Digital I/O
(Open-Drain)
Can be used to detect the state of CPU2 IERR or a general purpose
open-drain digital I/O
VRD1_HOT 9 Digital Input CPU1 voltage regulator HOT
VRD2_HOT 10 Digital Input CPU2 voltage regulator HOT
SCSI_TERM1 11 Digital Input SCSI Channel 1 termination fuse. Could also be used as a general
purpose input to trigger an error event.
SCSI_TERM2 12 Digital Input SCSI Channel 2 termination fuse. Could also be used as a general
purpose input to trigger an error event.
SMBDAT 13 Digital I/O
(Open-Drain)
Bidirectional System Management Bus Data. Output configured as
5V tolerant open-drain. SMBus 2.0 compliant.
SMBCLK 14 Digital Input System Management Bus Clock. Driven by an open-drain output,
and is 5V tolerant. SMBus 2.0 Compliant.
ALERT/XtestOut 15 Digital Output
(Open-Drain)
Open-drain ALERT output used in an interrupt driven system to
signal that an error event has occurred. Masked error events do not
activate the ALERT output. When in XOR tree test mode, functions
as XOR Tree output.
RESET 16 Digital I/O
(Open-Drain)
Open-drain reset output when power is first applied to the LM93.
Used as a reset for devices powered by 3.3V stand-by. After reset,
this pin becomes a reset input. See section 6.2 for more information.
AGND 17 GROUND Input Analog Ground
V
REF
18 Analog Output 2.5V used for external ADC reference, or as a V
REF
reference
voltage
REMOTE1− 19 Remote Thermal
Diode_1- Input (CPU
1 THERMDC)
This is the negative input (current sink) from the CPU1 thermal
diode. Connected to THERMDC pin of Pentium processor or the
emitter of a diode connected MMBT3904 NPN transistor. Serves as
the negative input into the A/D for thermal diode voltage
measurements. A 100 pF capacitor is optional and can be
connected between REMOTE1− and REMOTE1+.
REMOTE1+ 20 Remote Thermal
Diode_1+ I/O (CPU1
THERMDA)
This is a positive connection to the CPU1 thermal diode. Serves as
the positive input into the A/D for thermal diode voltage
measurements. It also serves as a current source output that
forward biases the thermal diode. Connected to THERMDA pin of
Pentium processor or the base of a diode connected MMBT3904
NPN transistor. A 100 pF capacitor is optional and can be
connected between REMOTE1− and REMOTE1+.
LM93
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