Laird 455-00030 Sterling EWB Development Kit Hardware User Guide

455-00030 Sterling EWB Development Kit Hardware
User Guide
Date 17 July 2019
06 Aug 2019
18 Sept 2020 11 Mar 2020

Sterling-EWB Development Kit
Hardware User Guide

REVISION HISTORY

Jonathan Kaye

OVERVIEW

The Laird Sterling-EWB development kit provides a platform for the 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.

connector

Applicable to the following Sterling-EWB module part numbers:

Note: For information about the AT Command software, please reference the AT Command Set Guide. The AT Command software can be programmed and utilized on any of the above part numbers.

PACKAGE CONTENTS

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.
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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.

DEVELOPMENT KIT – MAIN DEVELOPMENT BOARD
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.

Key Features

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 onboard 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 run to peripheral devices on the development board to allow disconnection.

• 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

• The optional footprint for Apple MFI co-processor (not populated)

• The optional footprint for Microchip ATECC608A-SSHDA authentication IC (not populated)

UNDERSTANDING THE DEVELOPMENT BOARD

Figure 1: Development board contents and locations

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)

FUNCTIONAL BLOCKS

Figure 4 shows the EWB development board power supply tree.
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 the 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 follows on the development board:

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.
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
6.2 Module Reset Button
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.
6.3 USB Programming and Debug Interface
The micro-USB connector J24 is used in conjunction with an 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.
6.4 Boot Option Configuration Switches
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

6.5 DVK Disconnect Switches
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.
6.6 UART Interfaces
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

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.
6.7 Indicator LEDs
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

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.
6.8 Push Buttons
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

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.
6.9 MCU Wake Button
SW1 is an 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.
6.10 BME680 Gas/Pressure/Temperature/Humidity Sensor
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.
6.11 External Host Interface
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

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 OEM 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).

Figure 7: External HOST interface schematic and location of solder bridge modifications

**BREAKOUT CONNECTOR PINOUTS

**

7.1 Trace debugging (JT AG) Interface
The development board provides access to the EWB module J-Link JTAG interface via connector J10 (Figure 8).

Figure 8: JTAG Interface schematic
7.2 Bluetooth Interface
Development board header J3 provides access to the Bluetooth radio on the EWB module (Figure 9).
Figure 9: Bluetooth Interface PIN assignments
7.2.1 Bluetooth PCM Audio Interface
Four PCM audio connections are available.
BT_PCM_CLK, BT_PCM_IN, BT_PCM_OUT, and BT_PCN_SYNC
BT_PCM_CLK and BT_PCN_SYNC can be master (output) or slave (input).|
7.2.2 Bluetooth GPIO Interface
Three Bluetooth General Purpose I/O lines are available for expansion capability.
7.2.3 Bluetooth Wake Interface
BT_HOST_WAKE output signal pin indicates when the EWB module Bluetooth radio requires attention.
7.3 PIN Breakout Headers
Access to the remaining EWB module signal pins is available on 0.1-inch pitch header connectors J5 and J6 (Figure 10 and Table 6).

Figure 10: EWB breakout headers
Table 6: J5 and J6 pin mapping Pin Connection Pin

 OTHER FEATURES

8.1 Current Consumption Measurements
The provided headers on the development board allow you to break the power supply lines and measure current consumption. J1 (3V3_WIFI), J19 (3V3_MCU), and J15 (3V3_VDD) are available to connect an ammeter between the two pins. To enable a current measurement, the shorted solder bridge at each header will need to be cut first (Figure 11). Figure 11: Current measurement schematic and PCB modifications
The mapping of the EWB module pinout to the STM32F412 MCU ports is provided in Table 7.
Table 7: EWB module to STM32 port mapping

[1] SPI1 is used for the internal EWB module 16 Mb flash communication (PA4, PA5, PA6, and PA7).

10 APPENDIX B-EWB/STM32F412 ALTERNATIVE FUNCTIONS

Note: USART2 is used internally on the EWB module for MCU to radio communication and is not available. SPI1 is used for the internal EWB module 16-Mb flash communication (PA4, PA5, PA6, and PA7).
ADDITIONAL DOCUMENTATION
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 accessed from the Sterling-EWB Product Page: https://www.lairdconnect.com/wireless-modules/wi- fi-bt-modules/sterling-ewb-iot-module
For any additional questions or queries, or to receive technical support for this Development Kit or for the Sterling-EWB module, please contact Embedded Wireless Solutions Support: https://www.lairdconnect.com/resources/support
© Copyright 2019 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. LairdTM, Laird TechnologiesTM, 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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References

• USB TTL Serial Cable Series - FTDI
• Ezurio | Laird Connectivity is now Ezurio
• AT Command Guide - Sterling EWB | Laird Connectivity
• Support
• Sterling-EWB IoT Module | Laird Connectivity

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