How to store/read the IMAGE files on the nRF52840 DK QSPI flash

This blog is to teach how to store the PNG image (converted to RGB 565) file into the external QSPI flash.

Assume all the PNG are 240×320 resolution, I target to use the Adafruit 1947 (ILI9341) board with nRF52840 DK in this demo.

The python script can be found at https://github.com/jimmywong2003/PNG-to-RGB565.

Convert the PNG Image file to C code include file and binary file.

python png2rgb565.py ..\picture\IMAGE_01.png result_output\IMAGE_01.h result_output\IMAGE_01.bin

python png2rgb565.py ..\picture\IMAGE_02.png result_output\IMAGE_02.h result_output\IMAGE_02.bin

python png2rgb565.py ..\picture\IMAGE_03.png result_output\IMAGE_03.h result_output\IMAGE_03.bin

python png2rgb565.py ..\picture\IMAGE_04.png result_output\IMAGE_04.h result_output\IMAGE_04.bin

python png2rgb565.py ..\picture\IMAGE_05.png result_output\IMAGE_05.h result_output\IMAGE_05.bin

Use the objcopy file to generate the HEX file assuming each size of image file is smaller than 0x40000 (256KB).

objcopy -v -I binary -O ihex --change-addresses 0x12000000 IMAGE_01.bin IMAGE_01.hex
objcopy -v -I binary -O ihex --change-addresses 0x12040000 IMAGE_02.bin IMAGE_02.hex
objcopy -v -I binary -O ihex --change-addresses 0x12080000 IMAGE_03.bin IMAGE_03.hex
objcopy -v -I binary -O ihex --change-addresses 0x120C0000 IMAGE_04.bin IMAGE_04.hex
objcopy -v -I binary -O ihex --change-addresses 0x12100000 IMAGE_05.bin IMAGE_05.hex

Erase the QSPI flash content on nRF52840 DK

if you need to use the qspi on the NRF52840 DK board, you need to include the

nrfjprog --qspicustominit 

It would call the qspidefault.ini (red color) instruction.

; Custom instructions to send to the external memory after initialization. Only used if –qspicustominit option is given in the call to nrfjprog. Format is
; instruction code plus data to send in between optional brakets. Numbers can be given in decimal, hex (starting with either 0x or 0X) and binary (starting
; with either 0b or 0B) formats. The custom instructions will be executed in the order found.
; This example includes two commands, first a WREN (WRite ENable) and then a WRSR (WRite Satus Register) enabling the Quad Operation and the High Performance
; mode for the MX25R6435F memory present in the nRF52840 DK.
InitializationCustomInstruction = 0x06
InitializationCustomInstruction = 0x01, [0x40, 0, 0x2]
nrfjprog -f nrf52 --qspicustominit --qspieraseall

Write the IMAGE (Hex) files on the QSPI flash

nrfjprog -f nrf52 --qspicustominit --program ..\result_output\IMAGE_01.hex  --sectorerase
nrfjprog -f nrf52 --qspicustominit --program ..\result_output\IMAGE_02.hex  --sectorerase
nrfjprog -f nrf52 --qspicustominit --program ..\result_output\IMAGE_03.hex  --sectorerase
nrfjprog -f nrf52 --qspicustominit --program ..\result_output\IMAGE_04.hex  --sectorerase
nrfjprog -f nrf52 --qspicustominit --program ..\result_output\IMAGE_05.hex  --sectorerase

Loading the image from QSPI flash

Initialize the QSPI

Define the IMAGE address

Loading image into the frame buffer RAM

2 thoughts on “How to store/read the IMAGE files on the nRF52840 DK QSPI flash

  1. i have a tftp display 2.4″ 320×240 and i have to display 30 types of animated emotion(emoji) on these display,also some of the emotion will be moving/dancing also,how much qspi flash memory will be require to keep all these image.
    for any moving/dancing display will i require more than one frame.


    1. It depends whether you would like to use any GUI or not. If you need to upgrade the full screen, you need to store 150KB per frame.
      Nordic SDK has the GFX example. You may have a look on such demo code for your reference.


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