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

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

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

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

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

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

python ..\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