Add new board.h definition BOARD_MAINOSC_BYPASS to configure the clock module to use an external oscillator rather than a crystal. The qmod board is one such board.
Change-Id: If62f55cd4c8b0cf758534f09d25a9bcb028814a7
For some reason undefined symbols were downgraded to warnings, which
means building a firmware that calls missing functions (= address zero)
was perfectly fine, which of course made development more exciting....
This applies to builtins, too, printf of one char gets downgraded to
putchar, which we don't have, so disable builtins.
Change-Id: I492f41ad4162b9d07b1881ae4aed019db2dff8b5
disabling the ERASE pin prevents accidental erase for the flash
memory while the board is powered on (e.g. in case the user
overcomes the weak 100 kOhm pull-down for more than 220 ms by
touching or shorting the pin).
the flash is still erasable using the ERASE pin during power up.
it is only disabled after boot completed.
Change-Id: Ic3332eb1d4247a07988b2fd841f40e79862d06a7
UART baud rate is main clock (MCK) divided by CR*16.
The MCK values are chosen >= 48 MHz and <= 64 MHz to have a near
integer value CR for a baud rate of 921600 bps.
The end MCK frequency between simtrace and qmod differ slightly
but are close to 58 MHz.
Change-Id: Iaa4a97fc68494c93b9d128503515d88049de506c
Sometimes there is some leakage current via some I/O that's sufficient
to power up the SAM3S. Use the supply monitor to make sure the CPU
will be reset (and kept in reset) if the supply voltage is below 3.0V.
This way we can easily check with 'diff' for differences in our code and
Atmel softpack. Also, this layout is more suitable for building various
different firmware images (e.g. factory-test, dfu-loader, main
application) for a variety of different boards (simtrace, owhw, qmod).