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QSPI NOR Flash

Overview

The QSPI NOR Flash sample demonstrates using the flash API on a QSPI NOR serial flash memory device. While trivial it is an example of direct access and allows confirmation that the flash is working and that automatic power savings is correctly implemented.

The QSPI NOR flash is connected to the nRF52840 chip over a QSPI bus. The table below shows the connections of each pin of QSPI flash:

QSPI Flash Pin nRF52840 Pin
CS# P0.17
SCLK P0.19
SIO0 P0.20
SIO1 P0.21
SIO2 P0.22
SIO3 P0.23

Requirements

Before you start, check that you have the required hardware and software:

Building the sample

Before you start building, remember to set up the environment first.

Use the following steps to build the QSPI NOR Flash sample on the command line.

  1. Open a terminal window.

  2. Go to my-workspace/ncs-playground directory created in the Setting up the environment section.

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    cd my-workspace/ncs-playground

  3. Build the sample using the west command, specifying the board (following the -b option) as connectkit_nrf52840:

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    west build -p always -b connectkit_nrf52840 samples/qspi_flash

    Tip

    The -p always option forces a pristine build, and is recommended for new users. Users may also use the -p auto option, which will use heuristics to determine if a pristine build is required, such as when building another sample.

  4. After running the west build command, the build files can be found in build/zephyr.

Flashing the firmware

The sample is designed to work with the UF2 Bootloader, so that you can easily flash the sample using the UF2 Bootloader. The firmware can be found in build/zephyr with the name zephyr.uf2.

To flash the firmware, complete the following steps:

  1. Push and hold the USER button and plug your board into the USB port of your computer. Release the USER button after your board is connected. The RGB LED turns green.

  2. It will mount as a Mass Storage Device called UF2BOOT.

  3. Drag and drop zephyr.uf2 onto the UF2BOOT volume. The RGB LED blinks red fast during flashing.

  4. Reset the board and the sample will start running.

Testing

After flashing the firmware to your board, complete the following steps to test it:

  1. Connect nRF52840 Connect Kit to your computer using the USB-C Cable.

  2. Open up a serial terminal, specifying the correct serial port that your computer uses to communicate with the board:

    Open up a terminal and run:

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    screen <serial-port-name> 115200
    1. Start PuTTY.

    2. Configure the correct serial port and click Open:

  3. Observe the output of the terminal. You should see the output, similar to what is shown in the following:

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    mx25r6435f@0 QSPI flash testing
==========================

Test 1: Flash erase
Flash erase succeeded!

Test 2: Flash write
Attempting to write 4 bytes
Data read matches data written. Good!!