EVAL-ADM1028 Datasheet, PDF (4/9 Pages) Analog Devices – Evaluation Board for PC Temperature Monitor and Fan Control ASIC

EVAL-ADM1028
CONNECTORS AND SWITCHES AND INDICATORS
The function of the various connectors, switches and
indicators on the evaluation board are explained below.
CENTRONICS CONNECTOR (J1)
The evaluation board may be connected to the personal
computer via the parallel printer port using the centronics
cable provided.
POWER CONNECTORS (J2 & J3)
Power is supplied to the board via J2 using a 15V Power
Supply mains adaptor. This adapor is not included in the
evaluation kit. Alternatively power may be supplied to the
board via J3 thus allowing a desktop power supply to be
used.
TEST CONNECTOR (J4)
J4 is provided as a test connector on the ADM1028
evaluation board. Each pin of the ADM1028 is connected
directly to the corresponding pin of the test connector thus
allowing the user easy access to all signals to and from the
ADM1028 (i.e. pin 1 of the ADM1028 is connected to
pin 1 of the test connector).
An off board thermal sensor may be connected as the
external sensor via pins 9 and 10 of the test connector.
SMBUS INTERFACE CONNECTOR (J5)
The SMBus interface connector allows the evaluation
board to be connected to the SMBus of a personal
computer using a DIMM interface card. To make this
connection it may be necessary to remove one of the
DIMM memory modules on the PC motherboard, if all
DIMM sockets are occupied. This will affect the BIOS
setup and Windows 95 and should only be attempted by a
competent user.
ON/OFF SWITCH (S1)
This is simply an on/off switch for the evaluation board.
REMOTE DIODE SWITCH (S2)
This switch allows the user to choose between the on-
board remote temperature sensor (Q3) and one that can be
connected to the test connector J4. When the switch is in
the on position the Q3 is selected. When it is in the off
position the off board sensor is selected.
R_RST INDICATOR (D2)
Writing a 1 to the R_RST Register of the Remote
Function Register causes the R_RST pin to be pulsed low
for a minimum of 125µs. This bit will self clear to 0 when
the R_RST pulse is complete. As a result the LED will
only light for the duration of the pulse.
R_OFF INDICATOR (D3)
Writing a 1 to the R_OFF bit of the Remote Function
Register causes the R_OFF output to be driven high. This
in turn causes the R_OFF LED to light. This bit is
cleared only when RST is asserted, i.e. the LED will
remain lighting until the RST button (PB3) is pressed.
THERMA & THERMB INDICATORS (D4 & D5)
These LED’s light when the THERM temperature limits
are exceeded for more than three consecutive
measurements. THERMA and THERMB are functionally
identical. THERMA has an internal pullup to 3.3V while
THERMB is open drain and can be pulled up to any
required voltage. See datasheet for more information.
The LED’s will switch off when the temperature falls to
5°C below the THERM limit for three consecutive
measurements
INTERRUPT LED (D6)
This LED illuminates whenever the ADM1028 issues an
interrupt signal (eg.when an out of limit measurement is
made). For more information on the various conditions
which cause INT to be pulled low plesase see the
datasheet.
POWER LED (D7)
This LED will illuminate whenever power is supplied to
the board and S1 is in the ON condition.
GPI INPUT SWITCH(PB1)
This switch essentially allows the user to generate an out
of limit measurement for the GPI (General Purpose
Input). This should result in an INT being generated if
the GPI interrupt is not masked.
AUXRST SWITCH (PB2)
Pulling AUXRST low will reset the ADM1028.
AUXRST is an input to the ADM1028. Pressing the
AUXRST switch will reset the ADM1028, setting all the
registers to their default values.
FAN_OFF INDICATOR (D1)
When the FAN_OFF pin is asserted low this indicates a
request to switch off the fan regardless of the fan_spd
output. When this occurs the FAN_OFF LED will light.
When the pin is asserted high again the LED will switch
off immediately. The FAN_OFF pin is asserted low when
bit 5 of the configuration register is set to 0. This bit
defaults to 1 on power up.
RST SWITCH (PB3)
This pin can be pulled low externally to indicate that to
the ADM1028 that the main system power has been
removed. This will cause the ADM1028 to shut off its
FAN_SPD output and reset its R_OFF output.
–4–
REV. PrA