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Korlinx

NX15 Module Integration FAQ

This FAQ covers common questions when integrating NX15 into a custom PCB.

note

This FAQ focuses on module integration. BLE application behavior, GATT design, and low-power firmware tuning are covered in the NX15 Series BLE Module section.

Model Selection​

Which NX15 model should I choose?​

Choose based on antenna type and Flash requirement.

RequirementDirection
Integrated antennaChoose NX15i variant
External antennaChoose NX15E variant
External Flash requiredChoose 32 model
No external Flash requiredChoose 00 model

See:

Should I choose chip antenna or u.FL?​

OptionUse When
Chip antennaYour PCB and enclosure can follow antenna keep-out rules
u.FL external antennaYou need flexible antenna placement or external antenna positioning

If the enclosure has metal parts or the antenna area is constrained, evaluate the u.FL external antenna option.

PCB Bring-up​

The board does not power on. What should I check?​

Check:

AreaCheck
VDD_nRFConfirm voltage is within the recommended operating range
GNDConfirm all GND pads are connected
Short circuitCheck VDD-to-GND resistance before power-on
DecouplingConfirm capacitors are installed near VDD pads
AssemblyInspect for solder bridge or misalignment

I cannot connect through SWD. What should I check?​

Check:

SignalCheck
SWDIORouted correctly and not shorted
SWDCLKRouted correctly and not shorted
GNDCommon ground between debugger and board
NRESETNot held low unexpectedly
VDDTarget board is powered
Debug accessHeader or test pads are accessible

The firmware flashes but does not run correctly. What should I check?​

Possible causes:

CauseCheck
Wrong board configurationConfirm pin mapping and board target
Power instabilityMeasure VDD during boot and radio activity
Reset issueCheck NRESET circuit
GPIO conflictCheck reserved pins and firmware pinctrl
External Flash mismatchConfirm model and Flash configuration

LGA and Soldering​

What should I inspect after reflow?​

Inspect:

ItemPurpose
Module alignmentConfirm correct placement
Solder jointsCheck pad wetting and solder bridge
Mechanical damageCheck crack or package damage
VDD-to-GND resistanceDetect short before power-on
Antenna areaConfirm keep-out was not violated

Can I clean the module after soldering?​

Cleaning is not recommended.

Avoid ultrasonic cleaning, liquid immersion, or aggressive solvent cleaning because it may damage the module or degrade RF performance.

See:

What if the floor life is exceeded?​

Follow the baking requirement before assembly.

See:

GPIO and Pin Usage​

Can every GPIO be used freely?​

No. GPIO availability depends on firmware configuration and model variant.

On Flash models, check whether QSPI-related pins are reserved before using them as GPIO.

See:

Which pins should always be accessible?​

At minimum, keep access to:

SignalReason
VDD_nRFPower measurement
GNDReference and debug
SWDIOFirmware programming/debug
SWDCLKFirmware programming/debug
NRESETReset and recovery
UART log pinsOptional bring-up log path

Antenna​

BLE signal is weak on my custom PCB. What should I check?​

Check:

AreaCheck
Module placementIs the antenna side placed near PCB edge?
Keep-outIs copper or ground placed in antenna clearance area?
MetalIs a shield, battery, or enclosure near the antenna?
u.FLIs connector soldered correctly?
RF traceIs the RF path 50 Ω with solid GND reference?

Can I change antenna placement after PCB layout?​

Antenna placement should be decided before PCB layout. Changing antenna type or module position later may require PCB redesign and RF re-validation.

Production​

What should be included in production test?​

Recommended checks:

TestPurpose
Power checkConfirm supply and current behavior
SWD programmingConfirm programming access
Firmware bootConfirm application starts
BLE advertisingConfirm radio operation
Current measurementConfirm no abnormal load
Visual inspectionConfirm assembly quality