Mboot builds do not use the external SPI flash in caching mode, and
explicitly disabling it saves RAM and a small bit of flash.
Signed-off-by: Damien George <damien@micropython.org>
This only needs to be enabled if a board uses FAT FS on external SPI flash.
When disabled (and using external SPI flash) 4k of RAM can be saved.
Signed-off-by: Damien George <damien@micropython.org>
Mboot now supports FAT, LFS1 and LFS2 filesystems, to load firmware from.
The filesystem needed by the board must be explicitly enabled by the
configuration variables MBOOT_VFS_FAT, MBOOT_VFS_LFS1 and MBOOT_VFS_LFS2.
Boards that previously used FAT implicitly (with MBOOT_FSLOAD enabled) must
now add the following config to mpconfigboard.h:
#define MBOOT_VFS_FAT (1)
Signed-off-by: Damien George <damien@micropython.org>
This change has the following effects:
- Reduces the resolution of the RTC sub-second counter from 30.52us to
122.07us.
- Allows RTC.calibration() to now support positive values (as well as
negative values).
- Reduces VBAT current consumption in standby mode by a small amount.
For general purpose use 122us resolution of the sub-second counter is
good enough, and the benefits of full range calibration and minor reduction
in VBAT consumption are worth the change.
