LVGL Terminal for PinePhone on Apache NuttX RTOS

LVGL Terminal lvglterm is a Touchscreen App for PinePhone that lets us run commands in the NuttX NSH Shell. Read the article...

• "NuttX RTOS for PinePhone: LVGL Terminal for NSH Shell"

• Watch the Demo on YouTube

LVGL Terminal is now in Mainline NuttX. To build LVGL Terminal...

1. Configure our NuttX Project...

   pushd nuttx/nuttx
   make distclean
   tools/configure.sh pinephone:lvgl
   make menuconfig

2. In "RTOS Features > Tasks and Scheduling"

   Set "Application entry point" to lvglterm_main

   Set "Application entry name" to lvglterm_main

3. In "Device Drivers"

   Enable "FIFO and named pipe drivers"

4. In "Library Routines > Program Execution Options"

   Enable "exec[l|v] / posix_spawn() Support"

5. In "Application Configuration > Examples"

   Enable "LVGL Terminal"

6. In "Application Configuration > NSH Library"

   Disable "Have architecture-specific initialization"

7. In "Application Configuration > Graphics Support > Light and Versatile Graphic Library (LVGL) > LVGL configuration > Font usage > Enable built-in fonts"

   Enable "UNSCII 16"

8. Save configuration and exit menuconfig

9. Build NuttX...

   make

10. If the NuttX Build fails with undefined reference to lv_font_unscii_16...

    LD: nuttx
    aarch64-none-elf-ld: /private/tmp/nuttx/nuttx/staging/libapps.a(lvglterm.c.private.tmp.nuttx.apps.examples.lvglterm.o): in function `create_widgets':
    /private/tmp/nuttx/apps/examples/lvglterm/lvglterm.c:254: undefined reference to `lv_font_unscii_16'
    aarch64-none-elf-ld: /private/tmp/nuttx/apps/examples/lvglterm/lvglterm.c:254: undefined reference to `lv_font_unscii_16'
    make[1]: *** [Makefile:173: nuttx] Error 1
    make: *** [tools/Unix.mk:537: nuttx] Error 2
    

    Clear the NuttX Build Configuration...

    make distclean
    tools/configure.sh pinephone:lvgl
    make menuconfig
    

    And redo the menuconfig steps from above, then rebuild.

    This happens because NuttX builds LVGL with the Makefile that's bundled with LVGL. And the Makefile Integration is a little wonky :-)

    FYI the font file is at...

    nuttx/apps/graphics/lvgl/lvgl/src/font/lv_font_unscii_16.c
    

    Which gets compiled to...

    nuttx/apps/graphics/lvgl/lv_font_unscii_16.c.*.apps.graphics.lvgl.o
    

    Which should define lv_font_unscii_16...

    $ aarch64-none-elf-objdump -t -S nuttx/apps/graphics/lvgl/lv_font_unscii_16.c.*.apps.graphics.lvgl.o
    ...
    0000000000000000 g     O .rodata.lv_font_unscii_16	0000000000000030 lv_font_unscii_16