I think the definition should be in the MCU, as the peripherals are the
same across a given family of the same processor — even if some MCUs
in a family may have a subset of those peripherals enabled. I think a
reasonable default (e.g. not all 0) is fine for the MCU to enable by
default as well: I’d like to see a UART by default on every board.
That said, I don’t really think I’d feel bad if the MCU peripherals
were all disabled by default and the BSP had to explicitly enable them
either. I think it would be great if newt could spit out a list of
everything enabled on a processor/port in an organized, easy to parse
fashion.
On 7 Feb 2018, at 12:19, markus wrote:
I went through a similar train of thought while porting the stm32f3
family, but then I realized I can argue both ways.
If the BSP doesn't route any of the pins of the peripheral it doesn't
matter if the MCU would support it. Or you might have to use a
different internal peripheral for UART_0, depending on BSP layout.
But yes, it does lead to a lot of code duplication (and therefore
maintenance). Maybe some master implementation of hal_bsp_init would
eliminate most of it.
One other thought I had was "maybe" the BSPs are mostly copies of each
other because most (all) BSPs in the repository are evaluation boards
and vendors typically try to use the same peripherals in all of their
evaluation boards to reduce above mentioned maintenance costs.
As I said, I can argue both ways...
Markus
On Wed, 7 Feb 2018 11:44:26 -0800
will sanfilippo <[email protected]> wrote:
Hello:
There has been some discussion in the larger community regarding the
proper place for the MYNEWT definitions for peripheral existence. For
example, these are definitions such as I2C_0, UART_0, etc.
In the past, these definitions were placed in hw/bsp/syscfg.yml. At
some point some of these were defined in hw/mcu/syscfg.yml.
My vote would be to place them in the MCU as it is the MCU that
“defines” the existence of these peripherals and that duplicating
them in each bsp that points to a speciifc MCU is redundant. Of
course, the BSP can override the MCU if desired.
Another side point: should the default definition define these
settings to be 0 or 1 by default? My vote, although I do not feel
strongly about this, would be to set them to 0 by default and let the
bsp or target set the appropriate values. My reasoning behind the bsp
actually setting them is that it is the bsp which actually
“defines”
which peripherals are used (ie the particular board may not use any
SPI or I2C and thus no need to set them to 1).
Thanks!
