Integration Manual

Table Of Contents
NORA-B1 series - System integration manual
UBX-20027617 - R04 Design-in Page 33 of 61
C1-Public
Figure 10: USB device power filtering and signal protection
R1 and/or C4 may only be necessary if EMC tests indicate additional filtering is required. R1
and C4 are marked as do not populate (DNP) here.
USB-IF certified cables are recommended.
4.6.3 SPI, QSPI, I2C, I2S, PDM
The layout of these communication buses should be designed so that noise injection and cross talk
are avoided.
4.7 NFC interface
The pins for the NFC interface can also be used as normal GPIOs. With NORA-B1 series modules,
ensure that the NFC pins are configured correctly in software. Connecting an NFC antenna to
the pins when configured as GPIO will damage the module.
The NFC antenna coil must be connected differentially between the P0.02/NFC1 and P0.03/NFC2
pins of the device.
Two external capacitors should be used to tune the resonance of the antenna circuit to 13.56 MHz.
The required tuning capacitor value is given by the below equations: an antenna inductance of L
ANT
=
2 μH will give tuning capacitors in the range of 130 pF on each pin. For good performance, match the
total capacitance on P0.02/NFC1 and P0.03/NFC2.
The NORA-B1 modules have been tested with 20 mm x 25 mm flexible trace antenna, so it is
recommended that the antenna design is kept close to these measurements. A smaller or larger
antenna can be used provided it is tuned to resonate at 13.56 MHz. To comply with European
regulatory requirements, the NFC antenna must be placed in such a way that the space between the