NuttX builtin up_udelay function uses BOARD_LOOPSPERMSEC configuration
value to determine how many loops need to be done to cause requested
delay. This does not match well with AVR DA/DB microcontrollers
because the CPU clock frequency is configurable.
A board configuration could therefore provide BOARD_LOOPSPERMSEC
valid for one frequency but for other frequencies, the user would
be required to calibrate the value and would still get incorrect
result when changing the clock speed during runtime.
This patch therefore implements dynamic architecture-specific
up_udelay function which determines current clock settings
and infers required loop count from that.
New function was tested by simple application that used up_udelay
to put delays between printf calls.
Signed-off-by: Kerogit <kr.git@kerogit.eu>
This patch adds support for Two-Wire interface in AVR Dx chips.
Only master mode is supported in this version.
The driver was tested using TC74Ax thermal sensor and simple application
that read the temperature from it. (Driver for the sensor is not in-tree.)
Signed-off-by: Kerogit <kr.git@kerogit.eu>
The document context-switch-notes.rst was leaking into "Supported Platforms"
table of contents. To fix this, it was moved to separate common directory
and referenced from AVR index.rst
Similar to that, the gpio_intr_mux.rst document was leaking into list
of supported AVR families. This too was fixed by moving it to separate
docs directory.
The change was tested by building the Documentation using make html
Signed-off-by: Kerogit <kr.git@kerogit.eu>
