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Use external SPI SRAM for frame-buffer

The commercial edition allows to use an external SPI SRAM as frame-buffer. The EXT3 extension board exposes pads for an SOIC-8 SPI memory, labelled U2.

The corresponding chip select pin is numbered 20 on the EXT3 extension board.

Configure

  • Open the configuration file hV_Configuration.h;

  • Set SRAM_MODE to USE_EXTERNAL_SPI:

#define SRAM_MODE USE_EXTERNAL_SPI
  • Ensure the chip select pin for the external SPI SRAM is defined for the board:
const pins_t myBoard =
{
    // ...
    .flashCSS = 38, ///< EXT3 pin 20 Black2
    // ...
};
Screen_EPD_EXT3_Fast myScreen(eScreen_EPD_EXT3_271_09,
    boardLaunchPad);

Caution

Do not specify a frame-buffer, as the library manages the external SPI SRAM internally.

  • Clean the previous build and launch a new compilation.

Use

The screen with external SPI SRAM behaves the same as with internal MCU SRAM. It is only slower.

Example

The example for external SPI SRAM is identical to the example for internal MCU SRAM.