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Upload fonts to external SPI Flash

The Commercial edition allows to use the external 8 Mbits = 1 MBytes x 8 SPI Flash memory, labelled U1 on the EXT3-1 extension board, to store fonts.

The standard reference of the SPI Flash memory is MX25V2006 . The corresponding chip select pin is numbered 8 on the EXT3-1 extension board.

Option 1: Segger J-Flash SPI

The Segger J-Link programmer-debugger offers a fast way to upload the fonts to the external SPI Flash of the EXT3. The List of supported SPI flash devices includes the MX25V2006.


Connect from the J-Link programmer-debugger to the EXT3: the SPI signals CLS, /CS, DI or MOSI, DO or MISO; and power lines VTref and GROUND.

To power the EXT3, either provide an external 3.3V; or connect a 3.3V regulator to the J-Link programmer-debugger 5V-Supply output and turn power on.


Two options: by command line or GUI.


JFlashSPI_CL -open Fonts_511.hex -auto

JFlashSPI_CL loads the Fonts_511.hex file, connects to the SPI Flash, uploads and verifies, then disconnects.

Launch the JFlashSPIExe application.

Call the menu File > Open data file… and select the Fonts_511.hex file; or drag-and-drop the Fonts_511.hex file onto the application.

Call the menu Target > Connect to identify the external SPI Flash automatically and then the menu Target > Program to upload and flash the external SPI Flash automatically.

Call the menu File > Exit to quit the application.

More information is available at the page J-Flash SPI — Direct programming of (Q)SPI flashes on the Segger website.

Option 2: highView Fonts Manager


Ensure the targeted MCU provides enough memory in Flash to store the fonts.

Open the hV_Fonts_Manager.ino project.

Set the options to write sector 0 and the font and generate the fonts enumeration.

#define WRITE_FLASH_SECTOR_0 1 ///< Write or update sector 0
#define WRITE_FLASH_FONTS 1 ///< Write fonts to Flash

#define SIMULATE_FLASH_SECTOR_0 0 ///< Simulate sector 0

#define READ_FLASH_SECTOR_0 1 ///< Read sector 0
#define READ_FLASH_FONTS 1 ///< Read fonts from Flash

#define GENERATE_FONTS_ENUMERATION 1 ///< Generate code of header file with fonts enumeration


Select the fonts to include under the setup() function.


Build and link, upload and run.

Copy the generated fonts enumeration into the hV_Font_Flash header file for later use with the Fonts from external SPI Flash option.