Laird Sterling-EWB User manual

Version 1.1

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Version
Date
Notes
Contributor(s)
Approver
1.0
17 July 2019
Initial version
Dave Neperud
Jay White
1.1
06 Aug 2019
Fixed typo in EWB development Kit power
supply diagram (Figure 4)
Dave Neperud
Jay White

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1Overview .............................................................................................................................................................................4
2Laird Sterling-EWB Development Kit Part Numbers............................................................................................................4
3Package Contents...............................................................................................................................................................4
4Development Kit –Main Development Board......................................................................................................................4
4.1 Key Features..............................................................................................................................................................4
5Understanding the Development Board...............................................................................................................................5
5.1 EWB-DVK Default Configuration and Jumper Settings..............................................................................................6
6Functional Blocks ................................................................................................................................................................7
6.1 Power Supply.............................................................................................................................................................7
6.2 Module Reset Button..................................................................................................................................................8
6.3 USB Programming and Debug Interface....................................................................................................................8
6.4 Boot Option Configuration Switches...........................................................................................................................8
6.5 DVK Disconnect Switches..........................................................................................................................................8
6.6 UART Interfaces.........................................................................................................................................................9
6.7 Indicator LEDs............................................................................................................................................................9
6.8 Push Buttons..............................................................................................................................................................9
6.9 MCU Wake Button....................................................................................................................................................10
6.10 BME680 Gas/Pressure/Temperature/Humidity Sensor............................................................................................10
6.11 External Host Interface.............................................................................................................................................10
7Breakout Connector Pinouts..............................................................................................................................................12
7.1 Trace debugging (JTAG) Interface...........................................................................................................................12
7.2 Bluetooth Interface...................................................................................................................................................12
7.2.1 Bluetooth PCM Audio Interface ..........................................................................................................................12
7.2.2 Bluetooth GPIO Interface ...................................................................................................................................12
7.2.3 Bluetooth Wake Interface...................................................................................................................................12
7.3 PIN Breakout Headers .............................................................................................................................................13
8Other Features ..................................................................................................................................................................14
8.1 Current Consumption Measurements.......................................................................................................................14
9APPENDIX A –EWB Module Pin to MCU Port Mapping...................................................................................................15
10 APPENDIX B –EWB/STM32F412 Alternative Functions..................................................................................................17
11 Additional Documentation..................................................................................................................................................18

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The Laird Sterling-EWB development kit provides a platform for development of embedded Wi-Fi and/or Bluetooth Low Energy
(BLE) applications. This document describes the development board hardware, highlighting the setup and interfaces available
to maximize user flexibility in developing these applications.
Part Number
Product Description
455-00030
Development Kit for 451-00001 module –Integrated chip antenna
455-00031
Development Kit for the 451-00002 module –w/ u.FL antenna connector
Applicable to the following Sterling-EWB module part numbers:
Part Number
Product Description
453-00014
Sterling-EWB chip antenna module –Integrated antenna
453-00013
Sterling-EWB U.FL module –External antenna
All kits contain the following items:
Development Board
The development board has the required Sterling-EWB module soldered onto it and exposes all
available hardware interfaces.
USB Cable
USB cable –Type A to micro type B.
The cable also provides serial communications via the FTDI USB –RS232 converter chip on the
board and powers the development board.
External 2.4GHz
dipole antenna
Supplied with development kit part # 455-00031 only.
External antenna, 2 dBi, FlexPIFA (Laird part #001-0014) with integral RF coaxial cable with 100
mm length and IPEX-4 compatible RF connector.
The Sterling-EWB development board is designed to be used directly with the Cypress WICED® SDK. The default
configurations provided in this document will enable operation and software development on this board.
The EWB development board has the following features:
▪Sterling-EWB series module soldered onto the development board
▪The following power supply options for powering the development board:
–USB (micro-USB, type B)
–External DC supply (4.4 –10V) –not supplied. Center positive barrel connector or header for bench supply.
–(4) AA batteries (not supplied)
▪Powering the EWB module using a single on-board regulator or separating the MCU and radio supplies to use individual
on-board regulators (SW8)
▪USB to UART/JTAG bridge (FTDI chip)
▪Pin headers for measuring current (EWB module only)
▪Selectable boot options
▪IO break-out 2.54 mm pitch pin header connectors that bring out all MCU interfaces of the EWB module –UART, SPI,
QSPI, I2C, SIO [DIO or AIN (ADCs)], I2S, PWM –and allow for plugging in external modules/sensors
▪IO breakout 2.54 mm pitch pin header for direct access to Bluetooth radio on the EWB module.
▪DIP switches on all EWB module IO lines running to peripheral devices on the development board to allow disconnection.

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▪J-Link JTAG header for access to EWB JTAG
▪2.54 mm pitch pin header connector and level-shifter supporting connection to an external host MCU (1.8V - 5.0V logic
levels).
▪On-board Bosch Sensortec BME680 environmental sensor
▪Two buttons and four LEDs for user interaction
▪One Reset button
▪One Wake button
▪Optional footprint for Apple MFI co-processor (not populated)
▪Optional footprint for Microchip ATECC608A-SSHDA authentication IC (not populated)
Sterling-EWB
Module
DC Jack
4.4-10V DC
Bench Supply
Header
4.4-10V DC
4xAA Battery
Terminal
Connector
USB2
(opt.)
External Host
Interface
Header (J4)
LED1 – LED4
External
3.3V USB
Header
SW8
Select single or
separate WIFI
3.3V power
supply
SW7
Select USB or
Ext DC power
source
Module
Reset
Button
USB1
Debug/Program
Interface
JTAG
Connector
SW5 & SW6
BOOT Option
Select
External
VBAT
Header
J5
EWB PIN
Header
J6
EWB PIN
Header
Bluetooth
Interface
Header
UART1
Header
DC Power
Indicator LED
J1 3.3V WIFI
Current
Measure
J15 3.3V DVK
Current
Measure
J19 3.3V MCU
Current
Measure
MCU Wake
Button
Gas/
Pressure/
Temp/
Humidity
Sensor
Authentication
IC (opt.)
MFI Co-processor
(opt.)
SW9, SW10, SW11
DVK peripheral
disable switches
UART3
Header
UART6
Header
SW12 DVK
peripheral disable
switch
UART
Activity
Indicator
LED
Figure 1: Development board contents and locations

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Figure 2: Development board 455-00030 (fitted with 453-00014 EWB module with integrated chip antenna)
IMPORTANT! To ensure correct out-of-the-box configuration, the EWB development board switches must be configured as
shown in Figure 3.
The default power connection is using the provided USB cable plugged into the DEBUG/PROGRAM micro-
USB port.
Figure 3: Correct EWB development board 455-00030 or 455-00031 switch settings (image for 455-00030)

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Figure 4 shows the EWB development board power supply tree.
DC Jack
(J18)
4x AA
(J8)
Bench
(J9)
microUSB
(J24)
microUSB
(J14)
D3
D4
D5
D6
SW7
POWER INPUT
SOURCE SELECT
USB
EXT
3.3V
Regulator
3.3V
Regulator
U5
U6
DEBUG
PROGRAM
OPTIONAL
USB
4.4 – 10V
4.4 – 10V
4.4 – 7.2V
SW8
EWB RADIO POWER
SOURCE SELECT
3V3_VDD 3V3_MCU 3V3_WIFI
SINGLE
SEPARATE
Figure 4: EWB development Kit power supply
There are five options for powering the development board:
▪DEBUG/PROGRAM USB port (micro-B connector) –If using the FTDI USB-UART path (Default)
▪OPTIONAL USB port (micro-B connector) –USB function is not supported/connected on the EWB module, but port can
be used as a power input
▪External DC supply (4.4V-10V), into DC jack connector (J18)
▪External DC bench supply (4.4V-10V) using 2-pin header (J9)
▪AA batteries –Four AA batteries connected to terminal block (J8)
The external power sources are fed into selection switch SW7 which allows the selection between either USB sources or the
external DC sources.
The external power source is regulated to a fixed 3.3V on the development board. Two regulators are on the development
board to provide the option to power the EWB module from a single supply or to separate the supplies for the EWB MCU
(3V3_MCU) and radio (3V3_WIFI) sections. The development board peripherals are also powered by U5 (3V3_VDD).
The EWB module power supply inputs are sourced as following on the development board:
3V3_WIFI
▪VDD_WIFI_PA (pin 9)
▪VDD_WIFI_IO (pin 41)
▪VDD_WIFI (pin 62)
3V3_MCU
▪VDD_MCU (pin 37)
▪VDD_USB (pin 35)
▪VBAT (pin 80)
Note: The EWB module currently does not support the external USB interface, so the VDD_USB pin is tied directly to
3V3_MCU. The VDD_USB pin supplies power to GPIO PA11 and PA12 on the EWB module.

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Note: The development board connects the VBAT pin directly to 3V3_MCU. An external battery voltage can be applied to
the EWB module by cutting SB1 to remove the connection to 3V3_MCU and applying a battery voltage to J22
(Figure 5).
The VBAT pin powers the battery power (RTC and backup registers) domain only when VDD is not present.
Figure 5: External VBAT power connector
The development board Module Reset button (SW4) connects directly to the EWB MICRO_RSTN pin and enables manual
reset of the module MCU when pressed.
The micro-USB connector J24 is used in conjunction with a FTDI FT2232H multipurpose USB UART/FIFO IC on the
development board to provide JTAG programming and UART1 serial port access to the STM32F412 MCU on the EWB
module.
The FT2232H has an external EEPROM which is pre-programmed with the custom VID (0x0A5C) and PID (0x43FA) to enable
the USB port to interface with the Cypress WICED® software development kit as well as provide a COM port for monitoring
the debug output of the Laird Sterling-EWB demo application.
The EWB development board boot option is configured by setting SW5 and SW6 (Figure 6).
Figure 6: BOOT configuration switches
Table 1: EWB boot source configuration
SW5 (BOOT 0)
position
SW5 (BOOT 1)
position
Boot Source
0
0 or 1
EWB Module boots from embedded User Flash (Default Setting)
1
1
EWB Module boots from Embedded SRAM
1
0
EWB Module boots from System Memory
The development board contains SPST DIP switches (SW9 –SW12) placed in-line with the EWB module I/O lines that
connect to peripheral devices on the board. This functionality is provided to maximize flexibility, allowing the user to disconnect
any EWB module I/O used by the development board, re-assign their functionality, and use them for development purposes.

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The EWB module is configurable for up to three UART interfaces which can be accessed through headers J7, J12, and J13 on
the development board.
Four-wire UART interfaces (TX, RX, CTS, RTS) are available on J12 (UART1) and J7 (UART3). J13 (UART6) only provides a
2-wire interface (TX, RX).
Note: UART1 is also driven by the FTDI FT2232H multipurpose USB UART IC to provide a terminal COM port
connection available at the micro-USB port (J24). To enable use of a direct external UART connection at J12,
SW12 positions 1 –4 must be switched to the OFF position.
The UART connections to the EWB module are shown in Table 2.
Table 2: EWB pin/UART connections available on development board
UART1 (J12)
UART1 (J12)
UART3 (J7)
UART6 (J13)
UART_TX (output)
PA9
PD8
PC6
UART_RX (input)
PA10
PC5
PC7
UART_RTS (output)
PA12
PB14
N/A
UART_CTS (input)
PA11
PB13
N/A
The UART header pinouts are designed to be used with FTDI USB-UART TTL (3.3V) converter cables (found at
http://www.ftdichip.com/Products/Cables/USBTTLSerial.htm). One example is FTDI part TTL-232R-3V3.
The development board includes six indicator LEDs.
Four LEDs (LED1 –LED4) are for development use and are connected to the MCU port of the EWB as indicated in Table 3.
Table 3: EWB LEDs and signal mapping
Designator
Color
STM32F412 Port Name
LED1
Green
PB12
LED2
Red
PB15
LED3
Blue
PE7
LED4
Red
PE8
Note: The MCU connections to the LEDs can be removed by switching positions 1 –4 of SW11 to the “OFF” position.
LED5 (Green) indicates when DC power is applied to the development board 3.3V regulator inputs.
LED6 (Green) indicates UART activity with the FTDI FT2232H USB UART/FIFO IC.
SW2 and SW3 are SPST-NO tact switches that when pressed will provide a low logic level input to the MCU port of the EWB
as indicated in Table 4.
Table 4: EWB button signal mapping
Designator
STM32F412 Port Connection
SW2
PC13
SW3
PD1
Note: The EWB MCU connection to the buttons can be removed by switching positions 3(SW3) and 6(SW2) of SW10 to
the OFF position.

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SW1 is SPST-NO tact switch connected to Port PA0 on the EWB STM32F412 MCU to provide the ability to use the WKUP
function of the MCU to wake from Standby, Stop, and Sleep modes of operation.
The development board includes the Bosch Sensortec BME680 air quality sensor connected to the EWB MCU I2C2 interface
bus via pins PB10 (SCL) and PB11 (SDA). The I2C signal traces are pulled high on the development board.
The EWB development board provides the capability to connect to an external host MCU that uses 1.8V - 5.0V logic levels.
The following peripherals and pin assignments of the EWB STM32F412 MCU are available on header J4 for connection to an
external microcontroller host platform (Table 5).
Table 5: External host Interface connections
J4 Pin #
Name
Function
Type
EWB STM32F412
Port
1
GND
Ground
I
-
2
VCC_EXT_MCU
External Host I/O Voltage[1]
I
-
3
UART_CTS
CTS flow control (to external host)
O
UART3_RTS/PB14
4
UART_TX
TX Data (from external host)
I
UART3_RX/PC5
5
UART_RX
RX Data (to external host)
O
UART3_TX/PD8
6
UART_RTS
RTS flow control (from external host)
I
UART3_CTS/PB13
7
RESETn
EWB MCU reset
I
MICRO_RST_N
8
WKUPn
EWB MCU wake
I
MICRO_WKUP/PA0
9
BT_WAKE
Wake up Signal indicating EWB Bluetooth device
requires attention
O
BT_HOST_WAKE
10
GPIO
General Purpose I/O
I/O
PE5
11
OEn
Level Shifter enable (active low)[2]
I
-
12
GND
Ground
I
-
Note: By default, EWB 3V3_MCU power is not provided to the level shifter interface IC on the development board.
[1] Connect EWB module 3V3_MCU to the level shifter and set the logic level for the module interface lines by
shorting solder bridge SB3 on the development board (Figure 7).
[2] The OEn line is held low by default on the development board. J4 - pin 11 provides the option for the external
host microcontroller to control this line. To allow this capability, the shorted solder bridge SB4 needs to be cut on
the development board (Figure 7).