Data Sheet

NINA-B40 series - Data sheet
UBX-19049405 - R04 Interfaces Page 12 of 40
C1 - Public
2.4 Low Frequency Clock (LFXO)
NINA-B40 modules require two clocks, a high frequency clock and a low frequency clock.
 The high frequency clock is provided on-module by a high-accuracy 32 MHz crystal as required by
the radio operation.
 The low frequency clock can be provided internally by an RC oscillator or synthesized from the fast
clock, or externally by a 32.768 kHz crystal. An external crystal provides the lowest power
consumption and greatest accuracy. Using the internal RC oscillator with calibration provides
acceptable performance for Bluetooth low energy applications at a reduced cost and slight
increase in power consumption.
For information about the LFXO operating parameters and performance of the clock, see Electrical
specifications, Table 13.
☞ When using an external crystal with NINA modules at operating temperatures above 85 ºC, certain
limitations apply. For further information, see the Nordic nRF52833 specification for extended
operating temperature. For Normal operating temperature range LXFO debounce time is 0.25s.
For extended temperature range LXFO debounce time is 0.50s.
2.5 Serial interfaces
NINA-B40 modules provide the following serial communication interfaces:
 2x UART interfaces: 4-wire universal asynchronous receiver/transmitter
 4x SPI interfaces: Up to four serial peripheral interfaces can be used simultaneously
 2x I2C interfaces: Inter-Integrated Circuit (I2C) interface for communication with digital sensors
 1x I2S interface: Used to communicate with external audio devices
 1x USB 2.0 device interface: The USB device interface to connect to the upstream host.
☞ Most digital interface pins on the module are shared between the digital, analog interfaces and
GPIOs. Unless otherwise stated, all functions can be assigned to any pin that is not already
occupied.
☞ Two of the SPI interfaces share common hardware with the I2C interfaces. These interfaces
cannot be used simultaneously. If both the I2C interfaces are in use only one SPI interface is
available.
2.5.1 Universal Asynchronous Receiver/Transmitter (UART)
The 4-wire UART interface supports hardware flow control and baud rates up to 1 Mbps. Other
characteristics of the UART interface are listed below:
 Pin configuration:
o TXD, data output pin
o RXD, data input pin
o RTS, Request To Send, flow control output pin (optional)
o CTS, Clear To Send, flow control input pin (optional)
 Hardware flow control or no flow control is supported.
 Power saving indication available on the hardware flow control output (RTS pin): The line is driven
to the OFF state when the module is not ready to accept data signals.
 Programmable baud rate generator allows most industry standard rates, as well as non-standard
rates up to 1 Mbps.
 Frame format configuration:
o 8 data bits
o Even or no-parity bit