NINA-B3 series - System integration manual 
UBX-17056748 - R13  System description  Page 12 of 72 
C1-Public 
1.7.4  I2C interface 
The Inter-Integrated Circuit (I2C) interfaces can be used to transfer or receive data on a 2-wire bus 
network. NINA-B3 can operate as both Central and Peripheral  on the I2C bus using both standard 
(100 kbps)  and  fast  (400  kbps)  transmission  speeds.  The  interface  uses  the  SCL  signal  to  clock 
instructions and data on the SDA signal. 
External pull-up resistors are required for the I2C interface. The value of the pull-up resistor should be 
selected  depending  on  the  speed  and  capacitance  of  the  bus.  See  Electrical  specifications  in  the 
NINA-B3 series data sheet [2] for recommended resistor values. 
1.7.5  USB 2.0 interface 
The NINA-B3 series modules include a full speed Universal Serial Bus (USB) device interface compliant 
with version 2.0 of the USB specification. The pin configuration of the USB interface is provided below: 
•  VBUS, 5 V supply input, required in order to use the interface 
•  USB_DP, USB_DM, differential data pair 
The USB interface has a dedicated power supply that requires a 5 V supply voltage for the VBUS pin. 
This allows the USB interface to be used even though the rest of the module might be battery powered 
or supplied by a 1.8 V supply, etc. 
1.8  GPIO pins 
In an un-configured state, NINA-B3 modules have 38 GPIO pins and no analog or digital interfaces. All 
interfaces or functions must be allocated to a GPIO pin before use. Eight of the 38 GPIO pins are analog 
enabled, meaning that they can have an analog function allocated to them. In addition to the serial 
interfaces, Table 5 shows the digital and analog functions that can be assigned to a GPIO pin.