Detailed Description of Hardware

User-Supplied SPI Interface

The USB-to-SPI dongle is an optional PCB that is only

needed to interact with the MAX31912/MAX31913 soft-

ware. The user has the option to supply an external SPI

interface to communicate with the devices. To connect a

user-supplied SPI interface, remove the dongle from J3

and connect an external SPI interface to the pins on J3.

Removing the dongle also removes the isolator so the

user may also want to provide an external digital isolator.

*These inputs have internal pullups.

Troubleshooting

All effort have been made to ensure that each kit works on

the first try, right out-of-the-box. In the rare occasion that

a problem is suspected, see Table 4 to help troubleshoot

the issue.

Table 2. Description of Jumpers

Table 1. Hardware Configurations

Table 3. Description of LEDs

LED

COLOR

DESCRIPTION

D1–D8

Red

Field Input LED Driver: Field input is logic-high.

D10

Red

Fault: MAX31912/MAX31913 has detected a fault. The field supply is too low or the IC

temperature is too high.

D50 (POWER)

Red

USB Power Fault: A fault occurred due to overvoltage limit, current limit, or thermal limit

Green

USB Power: USB power supply is on.

D51 (COM)

Red

Communication: After the software has initialized the hardware the LED flashes red when

a command from the PC is received.

Green

Initialized: Hardware has been initialized by software.

JUMPER

DESCRIPTION

J2

RIREF: Connects R1 to RIREF pin

J6*

DB0: Pulls DB0 down to GND

DB1: Pulls DB1 down to GND

MODESEL: Pulls MODESEL down to GND.

SIN: Pulls SIN down to GND

FIN1–FIN8 Field Inputs: Connects field input FINX to VIN

HARDWARE ACTION

COMPONENTS

DESCRIPTION

Connect field inputs

J5

Remove pullup jumpers FIN1–FIN8 and connect field inputs to J5.

Adjust current limit

J2

Remove jumper on J2 and connect external resistor to the RIREF pin on J2.

Connect other end of the resistor to GND.

Daisy-chain MAX31912/

MAX31913

SIN (J6)

Remove SIN jumper on J6 and connect external MAX31912/MAX31913

SOUT to SIN on J6.

Remove isolation

R58 – R61

On the USB-to-SPI dongle, populate 0Ω resistors on R58–R61.

Connect user-supplied SPI

interface

J3

Remove USB-to-SPI dongle from J3 and connect user SPI interface to J3

pins.

Note: This also removes the digital isolator. See the User-Supplied

SPI Interface section for more details.

Evaluate:

MAX31912/MAX31913

MAX31912/MAX31913 Evaluation Kits

www.maximintegrated.com

Maxim Integrated │ 4