Binary size optimization: saturn-v under 2 KiB

greatscottgadgets / saturn-v

DFU bootloader for SAMD11 and SAMD21 microcontrollers

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Binary size optimization: saturn-v under 2 KiB #3

Closed mndza closed 10 months ago

mndza commented 1 year ago

This patch set aims to reduce the saturn-v binary size to under 2 KiB in size.

Apollo must be modified to target a 2 KiB offset. Also, its binary size must be an even number.

Support for board revisions >=0.6 is also added. For earlier board revisions, make sure BOARD_REVISION_MAJOR and BOARD_REVISION_MINOR are set in your environment.

grvvy commented 1 year ago

I have this working on:

Cynthion rev: r0.4 gcc version 10.3.1 20210824 (release) (GNU Arm Embedded Toolchain 10.3-2021.10)

Notes:

Requires gcc version 10.3.1 specifically from arm: gcc version 10.3.1 20210824 (release) (GNU Arm Embedded Toolchain 10.3-2021.10)
- apt's version of 10.3.1 gcc version 10.3.1 20210621 (release) (15:10.3-2021.07-4) overflowed 2kB by 140 bytes
Requires case USB_DTYPE_String in usb.c to be wrapped in braces; mentioned above.