PicoCalc/Code/pico_multi_booter

PicoCalc multi booter

Here is a bootloader for PicoCalc combined slightly modified PicoMite and SD boot

• Pico1
• No sdcard inserted,load default app to run from flash.
• Sdcard inserted, SD boot menu will show up, load third pico app bin to run at FLASH TARGET OFFSET 2048k-152k

How to compile

export PICO_SDK_PATH=/where/picosdk/is
mkdir build
cd build
cmake ..
make

How to run

Just copy combined.uf2 into PicoCalc

PicoMite

configuration.h

#define FLASH_TARGET_OFFSET (920 * 1024)

sd_boot

config.h

#define SD_BOOT_FLASH_OFFSET         (152 * 1024)

SD Card Application Build and Deployment

Important Note:

Applications intended for SD card boot "MUST REBUILD" using a custom linker script to accommodate the program's offset(152k) address.

Applications intended for SD card boot is in **bin** format, not uf2.
 

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This section explains how to build and deploy applications on an SD card. Below is a simple example of a CMakeLists.txt for an application.

Step 1 Copy Custom Link Script

Copy memmap_sdcard_app.ld to your project repository.

Step 2 Add Custom Link Script to CMakeList.txt

In the project for multi boot, add custom link script to CMakeList.txt,usually at bottom.
We also need to use pico_add_extra_outputs to sure that there will .bin file generated.

...
pico_add_extra_outputs(${CMAKE_PROJECT_NAME})
...

function(enable_sdcard_app target)
  #pico_set_linker_script(${target} ${CMAKE_SOURCE_DIR}/memmap_sdcard_app.ld)
  if(${PICO_PLATFORM} STREQUAL "rp2040")
    pico_set_linker_script(${CMAKE_PROJECT_NAME} ${CMAKE_SOURCE_DIR}/memmap_default_rp2040.ld)
  elseif(${PICO_PLATFORM} MATCHES "rp2350")
    pico_set_linker_script(${CMAKE_PROJECT_NAME} ${CMAKE_SOURCE_DIR}/memmap_default_rp2350.ld)
  endif()
endfunction()

enable_sdcard_app(${CMAKE_PROJECT_NAME})

Build and Deployment Process

1. Build the project using the above CMakeLists.txt.

mkdir build; 
cd build
export PICO_SDK_PATH=/path/to/pico-sdk 
cmake ..
make

Step 3 Your Custom Application Is Ready For SD Card Boot

Once the build is complete, copy the generated .bin file to the /firmware directory of the SD card.