Sentrius BT610 Sensor

Board Overview

Sentrius BT610 Sensor

Name:

bt610

Vendor:

Ezurio

Architecture:

arm

SoC:

nrf52840

Browse board sources

Overview

The Sentrius™ BT610 Sensor is a battery powered, Bluetooth v5 Long Range integrated sensor platform that uses a Nordic Semiconductor nRF52840 ARM Cortex-M4F CPU.

The sensor has the following features:

• ADC

• CLOCK

• FLASH

• GPIO

• I2C

• MPU

• NVIC

• PWM

• QSPI

• RADIO (Bluetooth Low Energy and 802.15.4)

• RTC

• Segger RTT (RTT Console)

• SPI

• UART

• WDT

Sentrius BT610 Sensor, rear view

More information about the board can be found at the Sentrius BT610 website [1].

Hardware

Supported Features

The bt610 board supports the hardware features listed below.

on-chip / on-board

Feature integrated in the SoC / present on the board.

2 / 2

Number of instances that are enabled / disabled.
Click on the label to see the first instance of this feature in the board/SoC DTS files.

vnd,foo

Compatible string for the Devicetree binding matching the feature.
Click on the link to view the binding documentation.

bt610

/

nrf52840

bt610/nrf52840 target

Type	Location	Description	Compatible
CPU	on-chip	ARM Cortex-M4F CPU1	arm,cortex-m4f
ADC	on-chip	Nordic Semiconductor nRF family SAADC node1	nordic,nrf-saadc
ARM architecture	on-chip	Nordic UICR (User Information Configuration Registers)1	nordic,nrf-uicr
	on-chip	Nordic EGU (Event Generator Unit)6	nordic,nrf-egu
	on-chip	Nordic nRF family ACL (Access Control List)1	nordic,nrf-acl
	on-chip	Nordic nRF family MWU (Memory Watch Unit)1	nordic,nrf-mwu
Audio	on-chip	Nordic PDM (Pulse Density Modulation interface)1	nordic,nrf-pdm
Clock control	on-chip	Nordic nRF clock control node1	nordic,nrf-clock
Comparator	on-chip	Nordic nRF COMP (analog COMParator)1	nordic,nrf-comp
Counter	on-chip	Nordic nRF timer node5	nordic,nrf-timer
Cryptographic accelerator	on-chip	Nordic ECB (AES electronic codebook mode encryption)1	nordic,nrf-ecb
	on-chip	Nordic nRF family CCM (AES CCM mode encryption)1	nordic,nrf-ccm
	on-chip	ARM TrustZone CryptoCell 3101	arm,cryptocell-310
Debug	on-chip	ARMv7 instrumentation trace macrocell1	arm,armv7m-itm
Flash controller	on-chip	Nordic NVMC (Non-Volatile Memory Controller)1	nordic,nrf52-flash-controller
	on-chip	Properties defining the interface for the Nordic QSPI peripheral1	nordic,nrf-qspi
GPIO & Headers	on-board	TCA9538 GPIO1	ti,tca9538
	on-chip	NRF5 GPIOTE1	nordic,nrf-gpiote
	on-chip	NRF5 GPIO2	nordic,nrf-gpio
I2C	on-chip	Nordic nRF family TWI (TWI master)1	nordic,nrf-twi
	on-chip	Nordic nRF family TWIM (TWI master with EasyDMA)1	nordic,nrf-twim
I2S	on-chip	Nordic I2S (Inter-IC sound interface)1	nordic,nrf-i2s
IEEE 802.15.4	on-chip	Nordic nRF IEEE 802.15.4 node1	nordic,nrf-ieee802154
Input	on-board	Group of GPIO-bound input keys1	gpio-keys
Interrupt controller	on-chip	ARMv7-M NVIC (Nested Vectored Interrupt Controller)1	arm,v7m-nvic
LED	on-board	Group of GPIO-controlled LEDs1	gpio-leds
	on-board	Group of PWM-controlled LEDs1	pwm-leds
Miscellaneous	on-chip	Nordic FICR (Factory Information Configuration Registers)1	nordic,nrf-ficr
	on-chip	Nordic nRF family PPI (Programmable Peripheral Interconnect)1	nordic,nrf-ppi
MTD	on-chip	Flash node1	soc-nv-flash
	on-board	Fixed partitions of a flash (or other non-volatile storage) memory2	fixed-partitions
	on-board	QSPI NOR flash supporting the JEDEC CFI interface1	nordic,qspi-nor
Networking	on-chip	Nordic nRF family RADIO peripheral1	nordic,nrf-radio
	on-chip	Nordic nRF family NFCT (Near Field Communication Tag)1	nordic,nrf-nfct
Pin control	on-chip	The nRF pin controller is a singleton node responsible for controlling pin function selection and pin properties1	nordic,nrf-pinctrl
Power management	on-chip	Nordic nRF power control node1	nordic,nrf-power
PWM	on-chip	nRF PWM2 2	nordic,nrf-pwm
	on-chip	nRFx S/W PWM1	nordic,nrf-sw-pwm
Regulator	on-chip	Nordic nRF5X regulator (fixed stage of the core supply)1	nordic,nrf5x-regulator
	on-chip	Nordic nRF52X regulator (high voltage stage of the main supply)1	nordic,nrf52x-regulator-hv
	on-board	Fixed voltage regulators6	regulator-fixed
Retained memory	on-chip	Nordic GPREGRET (General Purpose Register Retention) device2	nordic,nrf-gpregret
RNG	on-chip	Nordic nRF family RNG (Random Number Generator)1	nordic,nrf-rng
RTC	on-chip	Nordic nRF RTC (Real-Time Counter)3	nordic,nrf-rtc
Sensors	on-chip	Nordic nRF family TEMP node1	nordic,nrf-temp
	on-chip	Nordic nRF quadrature decoder (QDEC) node1	nordic,nrf-qdec
	on-board	SM351LT magnetoresistive sensor1	honeywell,sm351lt
Serial controller	on-chip	Nordic nRF family UARTE (UART with EasyDMA)2	nordic,nrf-uarte
SPI	on-chip	Nordic nRF family SPIM (SPI master with EasyDMA)3	nordic,nrf-spim
	on-chip	Nordic nRF family SPI (SPI master)1	nordic,nrf-spi
SRAM	on-chip	Generic on-chip SRAM description1	mmio-sram
Timer	on-chip	ARMv7-M System Tick1	arm,armv7m-systick
USB	on-chip	Nordic nRF52 USB device controller1	nordic,nrf-usbd
Watchdog	on-chip	Nordic nRF family WDT (Watchdog Timer)1	nordic,nrf-wdt

Sentrius BT610 Sensor, board layout

Connections and IOs

LED

Two LEDs are visible through the BT610 housing lid. Note that the LEDs can be driven either directly, or via PWM. PWM should be used when current consumption is required to be minimised.

• LED_1 (red) = LED0 = P1.07 (Red LED 1)

• LED_2 (green) = LED1 = P1.03 (Green LED 2)

• LED_PWM_1 (red) = LED0PWM = P1.07 (Red PWM LED 1)

• LED_PWM_2 (green) = LED1PWM = P1.03 (Green PWM LED 2)

Push button

The BT610 incorporates three mechanical push buttons. Note these are only accessible with the housing cover removed.

Two of the buttons are available for use via the board DTS file, as follows.

• BUTTON_1 = SW0 = P0.24 (Boot button SW1)

• BUTTON_2 = SW1 = P1.01 (Tamper switch SW2)

A third mechanical push button is provided to allow reset of the on-board microcontroller.

Magnetoresistive sensor

The BT610 incorporates a Honeywell SM351LT magnetoresistive sensor. Refer to the Honeywell SM351LT datasheet [2] for further details.

• MAG_1 = SW2 = P1.15 (SM3531LT_0)

External flash memory

A 64Mbit external flash memory part is available for storage of application images and data. Refer to the Macronix MX25R6435FZNIL0 datasheet [6] for further details.

The flash memory is connected to the on-board QSPI device controller.

• MX25R64 = QSPI

Voltage reference

A precision 2.5V voltage reference is provided on the V_REF input for use during AD measurements.

This can deliver up to 50mA peak and 20mA continuous current.

Sensor connectivity

The BT610 incorporates three terminal blocks J5, J6 & J7 that allow connectivity to its sensor inputs, as follows.

Terminal Block J5

Pin No.	Name	Description	Direction
1	EXT_SPI_CS_2	External SPI CS 2	OUT
2	GND	GND	(N/A)
3	AIN4	Analog Input 4	IN
4	AIN3	Analog Input 3	IN
5	GND	GND	(N/A)
6	AIN2	Analog Input 2	IN
7	AIN1	Analog Input 1	IN
8	GND	GND	(N/A)
9	DIN2	Digital Input 2	IN
10	DO2	Digital Output 2	OUT

Terminal Block J6

Pin No.	Name	Description	Direction
1	DO1	Digital Output 1	OUT
2	DIN1	Digital Input 1	IN
3	GND	GND	(N/A)
4	THERM4	Thermistor Input 4	IN
5	THERM3	Thermistor Input 3	IN
6	GND	GND	(N/A)
7	THERM2	Thermistor Input 2	IN
8	THERM1	Thermistor Input 1	IN
9	GND	GND	(N/A)
10	B+ OUT	Ext. sensor power supply	(N/A)

Terminal Block J7

Pin No.	Name	Description	Direction
1	UART_1_RTS	UART 1 RTS	IN
2	UART_1_CTS	UART 1 CTS	OUT
3	UART_1_RXD	UART 1 RXD	IN
4	UART_1_TXD	UART 1 TXD	OUT
5	EXT_I2C_SCL	External I2C SCL	OUT
6	EXT_I2C_SDA	External I2C SDA	IN/OUT
7	EXT_SPI_CLK/TRACEDATA3	Ext. SPI CLK/TRACE DATA 3	OUT
8	EXT_SPI_MISO	External SPI MISO	IN
9	EXT_SPI_MOSI	External SPI MOSI	OUT
10	EXT_SPI_CS_1	External SPI CS 1	OUT

Analog inputs

The four external Analog Inputs are multiplexed to a single host microcontroller AD input, AIN_1, via a TI TMUX1204 multiplexer.

Refer to the TI TMUX1204 datasheet [4] for further details.

Signals up to 12V, to a maximum of 50mA, can be applied to the external Analog Inputs.

External Analog Input connections are made to the multiplexer as follows.

Input	MUX Input
AIN1	S1
AIN2	S2
AIN3	S3
AIN4	S4

A TI TCA9538 port expander is used to determine the mode of each Analog Input, for either voltage or current measurement, and also to control the mutliplexer. A high level applied to the appropriate expander port pin enables the associated analog input as a current input; when a low logic level is applied, voltage measurement mode is selected.

Refer to the TI TCA9538 datasheet [5] for further details.

The expander port connections are as follows.

Pin	Function
P0	AIN1 mode
P1	AIN2 mode
P2	AIN3 mode
P3	AIN4 mode
P4	MUX A0
P5	MUX A1
P6	(N/C)
P7	(N/C)

The following illustrates some possible configuration values for the port expander. Note that it is possible for combinations of voltage and current measurement to be applied such that some external Analog Inputs measure current and others voltage. This is not shown below.

Expander value	Selected Analog Input & mode
b’00000000’	AIN1, voltage measurement
b’00000001’	AIN1, current measurement
b’00010000’	AIN2, voltage measurement
b’00010010’	AIN2, current measurement
b’00100000’	AIN3, voltage measurement
b’00100100’	AIN3, current measurement
b’00110000’	AIN4, voltage measurement
b’00111000’	AIN4, current measurement

Circuitry associated with the analog input measurements can be disabled when not in use.

A GPIO is used to control this behaviour, as shown below.

ANALOG_ENABLE	Behaviour
0	Disabled
1	Enabled

Thermistor inputs

The four external thermistor inputs are connected to a single AD input, AIN_2, via a TI TMUX1204 multiplexer.

Refer to the TI TMUX1204 datasheet [4] for further details.

External analog input connections are made to the multiplexer as follows.

Input	MUX Input
THERM1	S1
THERM2	S2
THERM3	S3
THERM4	S4

The same port expander used to select external analog inputs is also used to select external thermistor inputs.

The table below defines possible values that can be written.

Expander value	Selected Analog Input
b’00000000’	THERM1
b’00010000’	THERM2
b’00100000’	THERM3
b’00110000’	THERM4

A GPIO line is used to enable electronics associated with thermistor measurement. This is controlled as shown below.

THERM_ENABLE	Behaviour
0	Enabled
1	Disabled

Note the thermistor circuit must be calibrated before use. A suggested method for achieving this is described in the BT610 Zephyr Application Thermistor Calibration [7] application note.

Digital inputs

Two external digital inputs are available for connection to external signals. For the digital level being applied to be detected, an appropriate output pin must first be set. This approach is taken to ensure supporting circuitry can be powered down when the input state is not being determined. When in use, the external digital input level can be read from the appropriate input pin.

The output and input pins required are as follows.

Enable Pin	Input Read Pin
DIN_1_ENABLE	DIN_1
DIN_2_ENABLE	DIN_2

Digital outputs

Two external digital outputs are available to provide signals to or to directly drive external equipment.

To provide a high level on the external digital output, a high logic level is applied to the appropriate host microcontroller output.

The output pins required are as follows.

Output Pin	External Sensor Terminal
DO_1_MCU	DO1
DO_2_MCU	DO2

External power supply

Power can be supplied to external sensors via the B+ OUT terminal. This is enabled by setting the BATTERY_OUTPUT_ENABLE GPIO line. In addition, the external supply can be boosted to 5V by setting the HIGH_SUPPLY_ENABLE GPIO line. When 5V is not selected, the external power supply follows the battery voltage.

Up to 50mA peak and 20mA continuous current can be delivered by the External Power Supply.

External sensor I2C port

External I2C sensors can be connected on the external I2C port. Note that external I2C sensors should be powered from the B+ terminal to ensure applied voltage levels match those expected internally by the board.

Required pins are as follows.

Output Pin	External Sensor Terminal
SCL_PIN	EXT_I2C_SCL
SDA_PIN	EXT_I2C_SDA

External sensor SPI port

Up to 2 external SPI sensors can be connected on the external SPI port. Note that external SPI sensors should be powered from the B+ terminal to ensure applied voltage levels match those expected internally by the board.

Required pins are as follows.

Output Pin	External Sensor Terminal
SCK_PIN	EXT_I2C_SCL
MOSI_PIN	EXT_I2C_SDA
MISO_PIN	EXT_SPI_MISO
SDA_PIN	EXT_I2C_SDA
CS_GPIOS	EXT_I2C_SDA
CS_GPIOS	EXT_I2C_SDA

Programming and Debugging

Applications for the bt610 board configuration can be built and flashed in the usual way (see Building an Application and Run an Application for more details); however, the standard debugging targets are not currently available.

The BT610 features a 10 way header, J3, for connection of a programmer/debugger, with pinout as follows.

Pin No.	Name	Description
1	3.3V	Power Supply, 3.3V
2	SWDIO	Data Input/Output
3	GND	GND
4	SWDCLK	Clock Pin
5	GND	GND
6	SWO	Trace Output Pin
7	(N/C)	Not Connected
8	(N/C)	Not Connected
9	GND	GND
10	nRESET	Reset Pin

Access to the sensor debug UART is facilitated by a 6 pin header, J1, with pinout as follows.

Pin No.	Name	Description	Direction
1	GND	GND	N/A
2	UART_0_RTS	UART 0 RTS Pin	IN
3	3.3V	Power Supply, 3.3V	N/A
4	UART_0_RX	UART 0 RX Pin	IN
5	UART_0_TX	UART 0 TX Pin	OUT
6	UART_0_CTS	UART 0 CTS Pin	OUT

Note that pin 3 requires a solder bridge to be closed to enable powering of the BT610 board via the UART connector.

Flashing

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).

Here is an example for the Hello World application.

First, run your favorite terminal program to listen for output.

NOTE: On the BT610, the UART lines are at TTL levels and must be passed through an appropriate line driver circuit for translation to RS232 levels. Refer to the MAX3232 datasheet [3] for a suitable driver IC.

$ minicom -D <tty_device> -b 115200

Replace <tty_device> with the port where the BT610 can be found. For example, under Linux, /dev/ttyUSB0.

Then build and flash the application in the usual way.

# From the root of the zephyr repository
west build -b bt610 samples/hello_world
west flash

Note that an external debugger is required to perform application flashing.

Debugging

The bt610 board does not have an on-board J-Link debug IC as some nRF5x development boards, however, instructions from the Nordic nRF5x Segger J-Link page also apply to this board, with the additional step of connecting an external debugger.

Testing Bluetooth on the BT610

Many of the Bluetooth examples will work on the BT610. Try them out:

• Peripheral

• Eddystone

• iBeacon

Testing the LEDs and buttons on the BT610

There are 2 samples that allow you to test that the buttons (switches) and LEDs on the board are working properly with Zephyr:

• Blinky

• Button

You can build and flash the examples to make sure Zephyr is running correctly on your board. The button, LED and sensor device definitions can be found in boards/ezurio/bt610/bt610.dts.

References

[1]

https://www.ezurio.com/iot-devices/iot-sensors/sentrius-bt610-io-sensor

[2]

https://sensing.honeywell.com/honeywell-sensing-nanopower-series-datasheet-50095501-c-en.pdf

[3]

https://www.ti.com/lit/ds/symlink/max3232.pdf

[4] (1,2)

https://www.ti.com/lit/gpn/TMUX1204

[5]

https://www.ti.com/lit/gpn/TCA9538

[6]

https://www.macronix.com/Lists/Datasheet/Attachments/7913/MX25R6435F,%20Wide%20Range,%2064Mb,%20v1.5.pdf

[7]

https://www.ezurio.com/technology/bt610-thermistor-coefficient-calculator