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Evaluates: MAX31825

MAX31825 Evaluation System

Pmod is a trademark of Digilent Inc.

General Description of Software

The main window of the MAX31825 EV kit software con-

tains controls to evaluate the MAX31825 IC.

Configuration Register

The

Configuration Register groupbox allows the user

to select the resolution, conversion rate, format, and

fault queue. Use the

Resolution drop-down list to select

between 9-, 10-, 11-, and 12-bits resolution. With each

resolution, the user can set the desired sampling rate

using the options in the

Conversion drop-down list. The

temperature can be adjusted between normal and extend-

ed format. In addition, users can set the fault queue from

1 or 4 consecutive faults. When the desired configuration

is set, click the

Write Scratchpad button to apply.

High and Low Fault

Adjust the

TH (Temperature High) and TL (Temperature

Low) edit boxes to the desired temperature thresh-

old. When the desired setting is set, click the

Write

Scratchpad button to apply.

When the ALARM output asserts in comparator mode, the

TH or TL fault status bits displays red until the tempera-

ture returns within the threshold range.

When the ALARM output asserts in interrupt mode, the

TH or TL fault status bits displays red until the read is

performed on any registers.

The ALARM also appears at the ALARM pin of the IC. To

check if the signal is high or low, use the

Check button

for the alarm status.

Address

The address is determined by the resistor/connection on

ADD0 and ADD1 pins of the MAX31825.

Detect Address

loads bits to status register. Refer to the IC data sheet for

the list of addresses. When multiple devices are on the

1-Wire bus, check the

Multi Devices checkbox before

clicking the

Detect Address button. Addresses are dis-

played on the

A5-A0 drop-down list. Once the desired

address is selected, click the

Set Address button before

sending function commands (

Write Scratchpad, Read

Scratchpad, and Convert T).

ROM

Within the

ROM Command groupbox, the controls include

Read ROM, Match ROM, Skip ROM, and Search ROM.

MAX31825 Commands

Within the

MAX31825 Command groupbox, the con-

trols include

Read Scratchpad, Write Scratchpad, and

Convert T.

Temperature

The temperature is displayed in the graph, hexadecimal

code, and converted temperature by clicking on the

Sample Continuously or Read Once button.

Logging Data

The temperature and raw code can be saved to a file.

Click the

Export to *.CSV button before collecting data.

General Description of Hardware

The MAX31825 EV system demonstrates the MAX31825,

1-Wire temperature sensor with address and alarm. The

USB2PMB2 module and the EV kit complete the system.

The DS2482 acts as the 1-Wire master for the MAX31825

To evaluate the EV kit with a user-supplied

connector J1 is a PMod™-compatible connector. If the

master does not have a PMod-compatible connector, then

make connection directly to the SCL, SDA test points.

Make sure the return ground is the same as the DS2482.

See Table 1 for jumper position.

User-Supplied 1-Wire

To evaluate the EV kit with a user-supplied 1-Wire bus,

See Table 1 for jumper position.

User-Supplied VDD

The MAX31825 is powered through USB by default when

a PMod-compatible master module is connected to the J1

connector of the EV kit. If the user-supplied VDD is used,

a PMod master module is not allowed on the J1 connec-

tor. In this case, remove the shunt from J6 jumper and

apply a voltage between +1.6V and +3.6V at the VCC0

test point and ground is connected at the GND1 test point.

User-Supplied VPU

The J2 jumper allows the user to apply their own pullup

voltage. When a shunt is on the 2-3 position, apply a volt-

age between +2.3V and +3.6V at the VPU test point and

verify the return path is connected at the GND test point.

#Denotes RoHS compliance.

PART

TYPE

MAX31825EVSYS1#

EV system (EV kit + Master Board)

MAX31825EVKIT#

EV kit

USB2PMB2#

Master Board

Ordering Information