This is the documentation for the latest (main) development branch of Zephyr. If you are looking for the documentation of previous releases, use the drop-down menu on the left and select the desired version.

Laird Connectivity BL654 Sensor Board

Overview

The BL654 Sensor Board hardware provides support for the Laird Connectivity BL654 module which is powered by a Nordic Semiconductor nRF52840 ARM Cortex-M4F CPU.

This sensor board has the following features:

  • ADC

  • CLOCK

  • FLASH

  • GPIO

  • I2C

  • MPU

  • NVIC

  • PWM

  • RADIO (Bluetooth Low Energy and 802.15.4)

  • RTC

  • Segger RTT (RTT Console)

  • SPI

  • UART

  • WDT

BL654 Sensor Board front and back

Fig. 81 BL654 Sensor Board front and back

BL654 Sensor Board connected to USB-SWD Programmer (UART and SWD access)

Fig. 82 BL654 Sensor Board connected to USB-SWD Programmer (UART and SWD access)

More information about the BL654 module can be found on the BL654 website 2, more information about the USB-SWD Programmer can be found on the USB-SWD Programmer website 4.

Hardware

Supported Features

The BL654 Sensor Board configuration supports the following hardware features:

Interface

Controller

Driver/Component

ADC

on-chip

adc

CLOCK

on-chip

clock_control

FLASH

on-chip

flash

GPIO

on-chip

gpio

I2C(M)

on-chip

i2c

MPU

on-chip

arch/arm

NVIC

on-chip

arch/arm

PWM

on-chip

pwm

RADIO

on-chip

Bluetooth, ieee802154

RTC

on-chip

system clock

RTT

Segger

console

SPI(M/S)

on-chip

spi

UART

on-chip

serial

WDT

on-chip

watchdog

Other hardware features have not been enabled yet for this board. See the BL654 website 2 for a complete list of BL654 module hardware features.

Connections and IOs

LED

  • LED1 (blue) = P0.16 (active low)

Push button

  • BUTTON1 (SW1) = P1.03 (active high)

Sensor

The BL654 Sensor Board has an on-board Bosch BME280 temperature/humidity/pressure sensor which is connected to the BL654 via I2C.

  • SCL = P0.27

  • SDA = P0.26

More information about the Bosch BME280 sensor can be found on the Bosch BME280 sensor website 1.

Powering the sensor

The sensor can be powered directly from a coin cell or from a voltage supplied on the UART pins, the board accepts voltage from 1.8v-3.3v. Note that if using a battery with a UART/debugger connected, the voltage of the UART/debugger (if it does not automatically sense/adjust) must be within 0.3v of the voltage of the coin cell to prevent suppression diodes in the nRF52840 silicon being activated or possible back-powering of the battery.

To power the board from an external source via UART, the solder bridge SB1 must be blobbed.

Programming and Debugging

Applications for the bl654_sensor_board board configuration can be built, flashed, and debugged in the usual way. See Building an Application and Run an Application for more details on building and running. An external debugger/programmer is required which can be connected to using a Tag-Connect TC2030-CTX cable, a Laird Connectivity USB-SWD Programmer board or Segger JLink programmer can be used to program and debug the BL654 sensor board.

Flashing

If using an external JLink, follow the instructions in the Nordic nRF5x Segger J-Link page to install and configure all the necessary software. Further information can be found in Flashing. Then build and flash applications as usual (see Building an Application and Run an Application for more details). If using a Laird Connectivity USB-SWD Programmer Board, see the pyOCD website 3 to find details about the software and how to install it.

Here is an example for the Hello World application.

First, run your favorite terminal program to listen for output - note that an external UART is required to be connected to the BL654 sensor board’s UART, if using the Laird Connectivity USB-SWD Programmer Board, the BL654 sensor board can be plugged in to the UART header. An FTDI cable can also be used - the voltage of the I/O lines and power line must be between 1.8v and 3.3v, do not connect an FTDI cable with a 5v power line to the BL654 sensor board.

J3 UART connector pinout (all pins referenced to operating voltage Vdd):

Pin No.

Name

Description

Direction

1

GND

GND

(N/A)

2

RTS

UART Ready-to-send pin

OUT

3

VDD

Supply voltage (requires SB1 to be blobbed)

(N/A)

4

RXD

UART Receive pin

IN

5

TXD

UART Transmit pin

(N/A)

6

CTS

UART Clear-to-send pin

IN

$ minicom -D <tty_device> -b 115200

Replace <tty_device> with the port where the BL654 sensor board can be found. For example, under Linux, /dev/ttyACM0.

The BL654 sensor board needs an external programmer to program it, any SWD programmer which has a 9-pin ARM debug port can be used with a Tag-Connect TC2030-CTX cable. If using the Laird Connectivity USB-SWD Programmer Board, connect the cable to P1 and ensure the board is set to supply power to the target at 3.3v.

J1 Tag-Connect SWD Pinout:

Pin No.

Name

Description

Direction

1

VDD

Operating voltage

(N/A)

2

SWDIO

Serial wire data input/output pin

IN/OUT

3

nRESET

Module reset pin

IN

4

SWCLK

Serial wire clock input pin

IN

5

GND

GND

(N/A)

6

SWO

Serial wire output pin

OUT

Then build and flash the application in the usual way.

# From the root of the zephyr repository
west build -b bl654_sensor_board samples/hello_world
west flash

Debugging

Refer to the Nordic nRF5x Segger J-Link page to learn about debugging Nordic based boards if using an external JLink debugger. If using a Laird Connectivity USB-SWD Programmer Board, pyOCD can be used for debugging.

Testing Bluetooth on the BL654 Sensor Board

Many of the Bluetooth examples will work on the BL654 Sensor Board. Try them out:

Testing the LED and button on the BL654 Sensor Board

There are 2 samples that allow you to test that the button (switch) and LED on the board are working properly with Zephyr:

You can build and flash the examples to make sure Zephyr is running correctly on your board. The button and LED definitions can be found in boards/arm/bl654_sensor_board/bl654_sensor_board.dts.

References

1

https://www.bosch-sensortec.com/products/environmental-sensors/humidity-sensors-bme280/

2(1,2)

https://connectivity.lairdtech.com/wireless-modules/bluetooth-modules/bluetooth-5-modules/bl654-series

3

https://github.com/pyocd/pyOCD

4

https://www.lairdconnect.com/usb-swd-programmer