EVB-ANT-1

EVB-ANT-1 is the application board for the Bluetooth Indoor Positioning kit from u-blox: XPLR-AOA-3. The board itself is directly connected to the antenna board ANT-B10. A detailed description of the hardware and its capabilities and components can be found here: XPLR-AOA-3-UserGuide.

The basic purpose of EVB-ANT-1 is to provide connectivity for the angle measurements data created by the antenna board.

EVB-ANT-1 Firmware

This open-source project is a basic firmware written for the MCU of EVB-ANT-1, which is an NXP RT1062. The firmware includes the main functionality and features for evaluating the antenna boards and setting up an indoor positioning system by using a position engine. The main software features are the following:

• Multithreaded implementation using freeRTOS
• Ethernet connectivity
• WiFi connectivity
• UART communication with the NINA-B4 module that runs the angle of arrival calculations
• UDP client for connecting to the positioning engine
• Flash memory storing and reading for configuration data (protected by CRC-check)
• HTTP server
• Web page with form for setting and reading configuration, as well as some controls

Downloading the code

• Clone the repository

Seting up the environment (MCUXpresso)

• Register to MCUXpresso website: http://www.nxp.com/mcuxpresso/ide
• Download MCUXpresso IDE (v11.6.0 or later)
• Open MCUXpresso IDE
• In the welcome page select "Download and install SDKs"
• Find board evkmimxrt1060, select it and press "Install"

Building using MCUXpresso IDE

• Open MCUXpresso IDE

• Inside Quickstart Panel select "Import project(s) from file system..."

• On "Root Directory" select "ax_app_project_buildup" folder and press "next" and then "Finish"

• To build the code, go to "Project" and select "Build Project"

Debugging using MCUXpresso IDE

Required Hardware: EVB-ANT-1, segger j-link, 9-Pin Cortex-M Adapter

• Set the dip switches on the evb to: 0-0-1-0

• Connect the segger j-link to the EVB-ANT-1 J8 (MCU JTAG) connector, using 9-Pin Cortex Adapter.

• On the 'Workspace' view, right click on the project name
• Go to "Debug as"
• Select "SEGGER J-Link probes"

Flashing through UART

The MCU has a bootloader that makes it possible to flash the firmware using its UART. The UART is driven to a usb-to-serial converter. So, it can be connected to a PC using a USB cable and it will appear as a virtual COM port. To Flash the firmware image, NXP MCUBootUtility tool is needed.

The firmware image can be found inside the project's 'Debug' folder with the name .axf. This file is generated by the IDE once you build the project with the 'Debug' configuration

• Download the third party tool MCUBootUtility from the following repository: https://github.com/JayHeng/NXP-MCUBootUtility

• Build project and obtain .axf file, or use the pre-built .axf file for the release (GitHub releases section)

• Set the dip switches on the evb to: 0-0-0-1 and then restart the MCU. This will make it enter in bootloader mode and expect a new image from the UART port.

• Connect evb to PC by using only a USB cable to the FTDI port (J13)

• Run the .exe file from the 'bin' folder of the NXP-MCUBootUtility repo

• Target setup: MXRT106x(-LFBGA196) with FLEXSPI NOR

• Port setup: the first COM number from the 4 enumerated virtual ports, Baud rate 115200
• Check 'one step' and press 'connect to ROM'

• Load the .axf file and press the 'All-in-one Action' button

The image should be flashed to the MCU

When flashing is complete, the user needs to bring the dip switches back to the position 0-0-1-0 and restart the MCU. This way the MCU will re-enter the normal operation mode

Configuring EVB-ANT-1

Out of the box, EVB-ANT-1 is preconfigured to use the ethernet interface with IP address 192.168.1.102 and subnet mask 255.255.255.0. The user can connect it to a router or directly to a pc afer configuring its network interface to the same subnet. Then by using a browser to view "http://192.168.1.102/", the user can configure all connectivity details for the device.

Wifi Setup

In the wifi setup section there are the fields:

• "Enabled" checkbox [1], that enables or disables the whole wifi interface.
• "SSID" and "Password" [2] that define the preferable wifi network in which the EVB-ANT-1 will try to connect after rebooting.
• "IP", "Subnet mask", "Default Gateway", "DNS Server 1", "DNS Server 2" [3], that define the configuration of the interface
• "DHCP checkbox" [4], for enabling dynamic ip allocation
• "RSSI" [5], that shows the signal of the network we are connected to, if any. Note that if DHCP is enabled, the above fields will be populated with the valid info

Ethernet Setup

Respectively, in the ethernet setup section there are the fields:

• "Enabled" checkbox [1], that enables or disables the ethernet interface.
• "IP", "Subnet mask", "Default Gateway", "DNS Server 1", "DNS Server 2" [2], that define the configuration of the interface
• "DHCP checkbox" [3], for dynamic ip alocation. Similarly to the WiFi section, the above fields also get the actual values in case of enabled DHCP

Positioning Engine Setup

In the positioning engine setup section, it is possible to set the parameters for the communication betwween EVB-ANT-1 and the positioning engine, using the fields

• "IP / Hostname" [1], set the IP or host name of the positioning engine.
• "Port" [2], set the destination port for sending the UDP packets with the angle measurements.

Anchor point Setup

In the anchor point setup section, there are:

• The "Active NINA module" dropdown menu [1]. In this selection we decide if we want to be using the NINA module of the ANT-B10 antenna board, or the secondary NINA module that is on the EVB board. The secondary NINA enables the user to experiment with different makes of antennas
• The three "NINA buttons" [2], that control the NINA modules. These button will apply the relative function directly on the selected NINA module upon pressing

Applying / Viewing Configuration

• 'Submit' button permanently saves the configuration to the device's memory
• 'Read' button refreshes the form with the corresponding data from the device.

NOTE: Most of the connectivity related parameters will not apply immediately after submitting, but will require restarting the device

Runtime info

At the end of the page, there is a realtime counter that continuously polls the MCU to get the time since last boot[1]. Also there is the "reboot" button [2] that applies a soft reset to EVB-ANT-1.

Resetting Configuration

If the "SW1" button of EVB-ANT-1 is pressed and held down during booting, the configuration would be reset to the initial values. That means that the configuration page will be accessible in address "192.168.1.102" of ethernet interface.

Web interface

The configuration page is written using HTML, CSS and JavaScript

The files are located in UI folder.

However, the http server that runs on the MCU needs to have them in a C array form.

For that purpose there is a script python arrayify_web_pages.py from the UI/tools which will replace the source/app/bip_httpsrv_fs_data.c with the updated UI.

Note: After updating the website files a hard refresh in the browser may be required to see latest changes.

SDK Notes

For this project we used NXP SDK EVK-MIMXRT1060, version 2.12.1 (NXP GitHub repository)

The following changes had to be made in SDK files:

lwip/port/enet_ethernetif.c:

Relevant discussion: https://community.nxp.com/t5/MCUXpresso-SDK/MCU-stops-if-ethernet-cable-is-not-plugged-in-on-startup/m-p/1371744

lwip/port/enet_ethernetif_kinetis.c:

Relevant discussion: https://community.nxp.com/t5/MCUXpresso-General/DTC-or-OC-SRAM/td-p/1302973