Introduction

The bootloader is built separately for each target device and board combination. This allows for compile-time customization of the bootloader.

Directory Structure

Target projects are stored in the top level targets directory. There is a subdirectory for each device. Inside the device directory is a directory for each toolchain and a src directory.

Sources

Each target must have several common source files:

bootloader_config.h

Configuration macros, see below.
clock_config_x.c

Clock configuration code.
hardware_init_x.c

Board-specific hardware related functions.
memory_map_x.c

Contains the memory map for the device.
peripherals_x.c

Contains the peripheral descriptor array.

(The "x" in the filenames above is replaced with the device name.)

Configuration options

The bootloader_config.h file in the target source directory sets a number of macros used to configure the bootloader build. These can be defined here or in the build tool project file.

BL_TARGET_FLASH

Selects the flash-resident build.

BL_TARGET_RAM

Selects the RAM-resident (flashloader) build.

BL_MIN_PROFILE

Selects between the maximal and minimal configuration for the bootloader. Set to 1 for the minimal configuration.

BL_FEATURE_READ_MEMORY

Forces inclusion of read memory command under minimal configuration.

BL_DEFAULT_PERIPHERAL_DETECT_TIMEOUT

The default active peripheral detection timeout in milliseconds.

BL_HAS_MASS_ERASE

Set to 1 if the device has the ERSALLU flash controller command. Only certain new devices have this command.

BL_FLASH_VERIFY_DISABLE

Set to 1 to disable verification of erases and writes to flash memory.

BL_ENABLE_CRC_CHECK

Enable application CRC check on targets with hardware CRC support.

BL_UART_AUTOBAUD_IRQ

Set to 1 to use pin interrupts for autobaud, rather than polling.

BL_APP_VECTOR_TABLE_ADDRESS

The bootloader will check this address for the application vector table upon startup.

BL_FEATURE_POWERDOWN

Enables entering low power mode if no host communication.

BL_DEFAULT_POWERDOWN_TIMEOUT

Sets timeout for entering low power mode.

BL_FEATURE_FLASH_SECURITY

Set to 1 if target supports flash security features.

BL_FEATURE_ENCRYPTION

Set to 1 if target supports encrypted application image download.

BL_FEATURE_QSPI_MODULE

Set to 1 if target has QSPI support.

The following macros control the inclusion of specific host communication peripherals in the build. (See peripherals_x.c.)

BL_CONFIG_SCUART

BL_CONFIG_I2C

BL_CONFIG_DSPI

BL_CONFIG_USB_HID

BL_CONFIG_USB_MSC