A
DVK-BT850-SA
DVK-BT850-ST
Version 1.1
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Version
Date
Notes
Contributors
Approver
1.0
12 Jan 2018
Initial Release.
Jacky Kuo
Raj Khatri
Jonathan Kaye
1.1
29 Jan 2020
Fixes to include DVK diagram, fixes to
part numbers (-Sx).
Updated to new template.
Rick Tretow
Dave Drogowski
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1 Overview ............................................................................................................................................................................. 4
2 Introduction .......................................................................................................................................................................... 4
2.1 Package Contents ...................................................................................................................................................... 4
3 DVK-BT850-Sx – Main Development Board ........................................................................................................................ 4
3.1 Getting to Know the Development Board ................................................................................................................... 5
4 Power Supply ......................................................................................................................................................................... 5
5 Interface Specification ............................................................................................................................................................ 6
5.1 GPIOs (PIN HEADER – J2) ....................................................................................................................................... 6
5.2 PCM/I2S Interface (Pin Header – J1) ......................................................................................................................... 7
5.3 DC Power Supply ....................................................................................................................................................... 7
5.4 Push Button ................................................................................................................................................................ 8
6 Other Features .................................................................................................................................................................... 8
6.1 Current Consumption Measurement .......................................................................................................................... 8
7 Additional Documentation .................................................................................................................................................... 9
8 Additional Assistance ........................................................................................................................................................ 10
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Laird’s BT850 development kit (DVK-BT850-Sx) provides a platform for rapid prototyping of BT850-Sx series modules. The
development board provides simple, easy-to-use access to the various hardware interfaces and configuration options for the
module. The DVK is the perfect platform to provide for early development testing of the BT850-Sx series features and
functionality, prior to designing the module onto a host PCB.
This datasheet is for the development board PCB which is DVK-BT850 1.0 on PCB.
The Laird DVK-BT850-Sx is designed to support the rapid development of applications and evaluation for the specific Laird
Bluetooth module part number BT850-SA or -ST. In-depth documentation for this product is available from the BT850 series
product pages: http://www.lairdtech.com/Products/BT850
Each DVK-BT850-Sx includes the following items:
Development motherboard
The motherboard has the BT850-Sx module already soldered onto it and all available
hardware interfaces are exposed.
USB cable – USB A type male
to Micro-USB type
The USB cable can be used to power, control, and configure the BT850-Sx.
Stand-off
Screw nuts x 4 pcs; Stand-off x 4 pcs
Insert card
Provides links to additional information including BT850-Sx datasheet, utilities,
schematics, and application notes.
External antenna
Only supplied with DVK-BT850-ST.
Antenna supplied is Laird part # 0600-00040.
DVK-
The development board allows the Laird Bluetooth module to be connected to a PC. The development board provides USB
interface linking to PCB and the BT850-Sx host interface. Any Windows PC (Windows 7 or later) auto-installs the generic
Microsoft Bluetooth driver.
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Figure 1: Main DVK-BT850-Sx Board
Table 1: Input voltage
Minimum
Typical
Maximum
Input Voltage
4.5V
5V
5.5V
Power supply options for powering development board:
▪ USB
▪ External DC supply
The DVK-BT850-Sx includes a USB cable to provide power to the development board. This should be plugged into a PC USB
port, a USB hub, or a main adaptor with a USB output. If a hub is used, it should be a powered USB hub to ensure sufficient
current is available at the port. The BT850-Sx module can be driven by the available current at a USB port.
The low noise LDO (U4) on the DVK-BT850-Sx provides the 3.3V to support the entire board’s operating voltage.
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INTERFACE SPECIFICATION
There are three GPIO signals (GPIO [5;6;7]) presented on pin header J2. These can be used for an LED indicator or Cypress
GCI (Global Coexistence Interface). The following (Table 2) shows the default settings by firmware.
Table 2: Default setting by firmware
GPIO
Function
GPIO_5
LED indications
GPIO_6
Cypress GCI; BT_SECI_IN (same as WLAN_Activity)
GPIO_7
Cypress GCI; BT_SECI_OUT (same as BT_Activity)
Note: All GPIOs functions are configured by firmware and any changes from the defaults would require a new firmware
load.
The pin descriptions of J2 are shown in Table 3.
Table 3: J2 pin descriptions
J2
Description
Direction
Pin-2
GPIO[5]
O
Pin-3
GPIO[7]
O
Pin-4
GPIO[6]
I
There are four LED indicators on the DVK-BT850-Sx as shown in Table 4.
Table 4: LED indicators
LED
Description
Function
LED1
Connected to the BT_SECI_I
Cypress GCI indication
LED2
Connected to the BT_SECI_OUT
Cypress GCI indication
LED3
Connected to the output of the U4 (LDO)
3.3V power supply rail indication
LED4
Connected to GPIO_5
For BT850-Sx of status indications including inquiry, connected,
and data traffic.
BR/EDR
Modes
▪ When in inquiry mode, the LED is flashing
with one-second periods.
▪ When the BT connection is created, the LED
is solid light state .
▪ When the BT has data traffic, the LED is
flashing with 250 ms periods
LE
Mode
▪ When in inquiry mode, the LED is flashing
with one-second periods.
▪ When the BT connection is created, the LED
is solid light state.
▪ When the BT has data traffic, the LED is
flashing with 250 ms periods
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Figure 2: Pin headers - J2
Figure 3: LED3
Figure 4: LED1, LED2, LED4
Note: The LED4 status configuration is controlled by firmware, any changes from the above default, please contact
Laird.
The DVK-BT850-Sx has a 4-wire digital audio port capable of operating in PCM or I2S mode; it isa dedicated audio interface
and cannot be used as general purpose GPIOs.
The pin descriptions of J1 in PCM/I2S are shown in Table 5.
Table 5: J1 Descriptions for PCM/I2S Interface
J11
Description (PCM/I2S/SPI)
Direction
Pin-1
GND
Pin-2
PCM_SYNC/I2S_WS
I/O
Pin-3
PCM_CLK/I2S_CLK
I/O
Pin-4
PCM_IN/I2S_DI
Input
Pin-5
PCM_OUT/I2S_OUT
Output
Pin-6
GND
Figure 5: Pin Headers - J11 for PCM/I2S
Interface
▪ USB Connector – The development kit provides a USB Type micro-USB connector (USB1) which allows connection to
any USB host device. The connector optionally supplies power to the DVK-BT850-Sx when SW2 is set to the USB
position.
▪ DC JACK – The development kit provided a DC JACK (CN1) for DC power supply input with an LDO (U4) to converting
input voltage to 3.3V. The operation voltage range of the LDO is from 2.5V to 5.5V and the current consumption is 1A
maximum. When using the DC JACK for supply voltage to the DVK-BT850, the SW2 need to set to the DC JACK
position.
Note: When using the LDO to generate a stable 3.3V, the DVK board supports +5V power supply only.
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Figure 6: Micro-USB Connector (USB1), SW2, and DC JACK (CN1)
SW4 (push button TACT switch) provides a reset signal to reset the BT850-Sx module.
Push Button
Label on DVK-BT850 PCB
Description
SW4
Reset
Reset the BT850-Sx module
Figure 7: SW4
A removable jumper (J3) is provided to break the power supply line directly to the module (if SB1 is cut), allowing you to
measure current consumption. For normal operation, J3 must be fitted. Error! Reference source not found.shows the
locations of SB1 and J3.
Note: This measures the current consumption of the BT850-Sx series module ONLY.
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Figure 8: Current measurement circuit
To prepare the board for current measurement, cut the shorting of the solder bridge SB1. After this modification, there are
two primary ways to measure the current consumption:
▪ Using Ammeter – Connect an ampere meter between the two pins of connector J3. This directly monitors the current.
▪ Using Oscilloscope (Note below) – Mount a resistor on the footprint R3. The resistor should not be larger than 10
Ohm. Connect an oscilloscope or similar with two probes on the pin on the J3 connector and measure the voltage drop.
The voltage drop is proportional with current consumption. If a one-Ohm resistor is chosen,
1 mV equals 1 mA.
There is also a third way to measure current:
▪ Using Current Shunt Monitor – The current drawn by the BT850-Sx module can be monitored using the Current Shunt
Monitor (CSM), INA216 (U3). The gain of INA216 is 200 V/V for lowest possible drop voltage.
Note: The Current Shunt Monitor method allows the dynamic current consumption waveforms on oscilloscope as
the BT850-Sx radio operates. This can provide insight into power optimization.
Current consumed by the BT850-Sx series module is measured as a voltage (that is proportional to the current) using the
CSM by connecting measuring voltmeter or oscilloscope to TP3 Connect measuring voltmeter or oscilloscope GND to TP2.
I(mA) = Vmeas_TP3(mV) /51
CAUTION: To avoid permanent damage to the IC U3 (the current shunt monitor), do not short the TP3 output to GND.
Laird offers a variety of documentation and ancillary information to support our customers through the initial evaluation process
and ultimately into mass production. Additional documentation can be found at the BT850 product page under the
documentation tab. It includes:
▪ BT850 – Class 1 BT4.2 Dual Mode HCI module – Product brief
▪ BT850 Datasheet - Hardware Integration Guide
▪ BT850 UART HCI Bluetooth Module for Linux – User’s Manual – Using the BT850 with the BlueZ Linux BCCMD tool
For any additional questions or queries or to receive local technical support for the DVK-BT850-Sx or BT850-Sxmodule,
please visit our support site at https://laird-ews-support.desk.com/.
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Hong Kong: +852 2923 0610
Please contact your local sales representative or our support team for further assistance:
Email: https://www.lairdconnect.com/contact
Phone: Americas: +1-800-492-2320
Europe: +44-1628-858-940
Hong Kong: +852 2923 0610
Web: http://www.lairdconnect.com/
© Copyright 2020 Laird. All Rights Reserved. Patent pending. Any information furnished by Laird and its agents is believed to
be accurate and reliable. All specifications are subject to change without notice. Responsibility for the use and application of
Laird materials or products rests with the end user since Laird and its agents cannot be aware of all potential uses. Laird
makes no warranties as to non-infringement nor as to the fitness, merchantability, or sustainability of any Laird materials or
products for any specific or general uses. Laird, Laird Technologies, Inc., or any of its affiliates or agents shall not be liable for
incidental or consequential damages of any kind. All Laird products are sold pursuant to the Laird Terms and Conditions of
Sale in effect from time to time, a copy of which will be furnished upon request. When used as a tradename
herein, Laird means Laird PLC or one or more subsidiaries of Laird PLC. Laird™, Laird Technologies™, corresponding logos,
and other marks are trademarks or registered trademarks of Laird. Other marks may be the property of third parties. Nothing
herein provides a license under any Laird or any third party intellectual property right.
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