GPIO LL headers might be included even when not using GPIO LL. Some
functions may be provided by the common header or the platform specific
one, depending on the features used. Hence, the header can only be
safely included if the correct set of GPIO LL hardware features is used.
The assumption that every MCU has this feature turned out wrong. Hence,
add a feature to allow testing for support of edge triggered IRQs on
both flanks.
This adds two functions:
void gpio_ll_switch_dir_output(gpio_port_t port, uword_t outputs);
void gpio_ll_switch_dir_input(gpio_port_t port, uword_t inputs);
The first configures GPIO pins specified by a bitmask as output, the
second configures the specified pins as input.
The main use case is to allow bit-banging bidirectional protocols using
more basic GPIO peripherals that do not implement open drain mode, such
as found e.g. on MSP430, ATmega, or SAM0.
It is not intended to implement this feature on modern MCUs with
sophisticated GPIO peripherals.
This adds the features
- periph_gpio_ll_input_pull_down:
To indicate support for input mode with internal pull down
- periph_gpio_ll_input_pull_keep:
To indicate support for input mode with internal resistor
pulling towards current level
- periph_gpio_ll_input_pull_up:
To indicate support for input mode with internal pull up
- periph_gpio_ll_disconnect:
To indicate a GPIO can be disconnected
- periph_gpio_ll_open_drain:
To indicate support for open drain mode
- periph_gpio_ll_open_drain_pull_up:
To indicate support for open drain mode with internal pull up
- periph_gpio_ll_open_source:
To indicate support for open source mode
- periph_gpio_ll_open_source_pull_down:
To indicate support for open source mode with internal pull down
