Hardware requirements

  • Micro USB cable

  • LPCXpresso55S28 board

  • Personal Computer

  • SD card

  • headphones with 3.5 mm stereo jack

  • source of sound (line output to 3.5 mm stereo jack)

Board settings

Insert the card(FAT32 formatted with testfile.txt in the root) into the card slot.

Prepare the Demo

Note: MCUXpresso IDE project default debug console is semihost

  1. Connect headphones to Audio HP / Line-Out connector.

  2. Connect source of sound(from PC or Smart phone) to Audio Line-In connector.

  3. Connect a micro USB cable between the PC host and the LPC-Link USB port (J8) on the board.

  4. Open a serial terminal with the following settings:

    • 115200 baud rate

    • 8 data bits

    • No parity

    • One stop bit

    • No flow control

  5. Download the program to the target board.

  6. Insert sdcard into sdcard.

  7. Reset the SoC and run the project.

Running the demo

When the demo runs successfully, the log would be seen on the terminal like:

Multi-peripheral Test!


Start datetime: 2020- 9-24 19:15: 0
AUDIO Loopback started!
Headphones will play what is input into Audio Line-In connector.
Accelerometer: Found Accelerometer!
USB device HID mouse test
Plug-in the device, which is running mouse test, into the PC.A HID-compliant mouse is enumerated in the Device Manager.
The mouse arrow is moving on PC screen in the rectangular rotation.

SDCARD: Write/read file ......

Write to testfile.txt.

Read from testfile.txt.
Compare the read/write content......
SDCARD Tested OK!

Press the WAKEUP button, the red LED will flash. Press the ISP button, the blue LED will flash. Press the USER button, the green LED will constant on.