rework bootloader's SPI flash access #321
Merged
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Triggered by #319 (by @jpf91) this PR reworks some of the bootloader's SPI flash functionality and configuration options:
WEL
(write enable latch) of the flash status register can be set and cleared again.0x04
: write disable - which is a standard commandSPI_FLASH_ADDR_BYTES
: number of address bytes (2,3,4) -> 2=16-bit, 3=24-bit, 4=32-bit, default = 3 / 24-bitThe SPI address size (as well as all other bootloader customization options) can be modified at compile time. Example (configuring 16-bit address width):
sw/bootloader$ make USER_FLAGS+=-D'SPI_FLASH_ADDR_BYTES=2' clean_all exe
📚 The bootloader's documentation is also updated accordingly by this PR.