stm32f7: Add basic PWM support to nucleo-144 board
More PWMs and multi channels support
may be investigated and added later.
It was tested on nucleo-f767zi
with those features enabled in configuration:
```
CONFIG_EXAMPLES_PWM=y
CONFIG_PWM=y
CONFIG_STM32F7_TIM1=y
CONFIG_STM32F7_TIM1_PWM=y
CONFIG_STM32F7_TIM2=y
(...)
CONFIG_STM32F7_TIM4_PWM=y
```
Change-Id: I08ebd4a538d15661788a0a54c2113ad767f22747
Bug: https://bitbucket.org/nuttx/nuttx/issues/153
Relate-to: https://github.com/rzr/webthing-iotjs/issues/3
Forwarded: https://bitbucket.org/nuttx/nuttx/pull-requests/862
Signed-off-by: Philippe Coval <p.coval@samsung.com>
Approved-by: Gregory Nutt <gnutt@nuttx.org>
This new configuration will showcase all the features of the boards, so is a good way to easily test out a new board. This can be added to all boards in the future.
