To make this happen, we need to have <board/board.h> tell us whether
or not it's got each of the USARTs. Do that with BOARD_HAVE_USARTn,
for n = 1,...,6. This lets us define HardwareSerial instances only
when appropriate, and gets rid of some board-specific hacks we'd
accumulated.
The new <libmaple/usart.h> now has a convenience function for
determining the bus rate by using the appropriate STM32_PCLKx macro,
so we can shave a uint32 per instance, which is nice given that
they're all going to be in memory. This changes the constructor
arguments, but the API only specifies the semantics of the predefined
instances, so this is still backwards-compatible. (We should look into
storing the instances in Flash -- they don't change, after all.)
We don't actually need struct usart_dev's definition in
HardwareSerial.h, so replace it with a forward declaration and include
<libmaple/usart.h> it in HardwareSerial.cpp instead.
Assert some copyrights.
Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
This supports ST's STM3220G-EVAL, the standard "kitchen-sink"
evaluation board for the STM32F2 series.
Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
