5
5
2.0 Getting Started (continued)
2.4 Test Setup – Hardware
Figure 2 below shows an example of a typical LM64 Evaluation Board test setup for driving fans,
attaching remote diodes, and monitoring the system.
Figure 2. Test Setup using the LM64 Evaluation Board
For the first time user, no jumpers are required on headers JP1, JP2, or JP3 for operation of the basic
temperature measuring and fan control functions. Details about these headers, and connections to
them, will be discussed later in this User Guide.
Hardware Test Setup Procedure
1. Before connecting the power supply to the LM64 Evaluation Board, turn it on and set the
output voltage to the voltage rating of the fan (+5 or +12 VDC). Turn the power supply off.
2. Connect the power supply to the LM64 Evaluation Board jack J2 as shown in Figure 2. Make
sure that the positive terminal is connected to V+ and the negative terminal is connected to the
GND of J2.
3. Plug in the fan as shown in Figure 2. This pinout is standard for PC processor fans.
4. The LM64 Evaluation Board comes with jumpers installed on J4, which connects the on-board
MMBT3904 diode-connected transistor to the input of the LM64 chip.
5. Connect the USB cable from the computer’s USB port to the LM64 Evaluation Board
6. Turn on the fan power supply.
7. Start the SensorEval software.
LM64
Fan Power
National Semiconductor
LM64 Evaluation Board
Tach
V+
V-
GND
A0
SDA
SCL
ALERT#
TCRIT
VDC
USB
V+
GND
Q1
J4
J2
J3
JP3
+12 VDC or +5 VDC
Fan Power Supply
No jumpers required.
May be used to test GPD’s and GPIO’s
No Jumpers
Required
Black Lead
Computer
USB
Port
Connection
G
P
D
5
G
P
D
4
G
P
D
3
G
P
D
2
G
P
D
1
JP1
GPIO5
GPIO4
GPIO3
GPIO2
GPIO1
JP2
D+
D-
Test
Socket
