If the GPIO is in an output state, gpio_init() can return 0 without bad
consequences.
-1 was return until now.
Signed-off-by: Gilles DOFFE <g.doffe@gmail.com>
Calling the initialization function ensures that the dummy lwIP library is used instead of the real lwIP, even if the esp_wifi module for esp8266 is not used.
The documentation had to be changed due to the relation of module `esp_now` to `esp_wifi` module. In addition, a number of corrections have been made. In the case of documentation, it is impossible to do this in various commits.
Usually, all .rodata sections are placed in RAM by the Espressif SDK since IROM (flash) access requires 32-bit word aligned reads. thanks to the LoadStoreError exception handler from esp-open-rtos which is used now in RIOT-OS, it is also possible to place .rodata sections in IROM (flash) to save RAM resources.
Usually, the access to the IROM (flash) memory requires 32-bit word aligned reads. Attempts to access data in the IROM (flash) memory less than 32 bits in size triggers a LoadStoreError exception. With the exception handler from esp-open-rtos it becomes possible to access data in IROM (flash) with a size of less than 32 bits and thus to place .rodata sections in the IROM (flash).
The default macros GPIO_PIN and GPIO_UNDEF do not have to be overridden. The GPIO_PIN macro definition was even wrong for 40 GPIOs without splitting into ports, even if that did not lead to erroneous behavior.
Add support for specifying data bits, stop bits and parity at
runtime.
Introduce feature periph_uart_modecfg for uart_mode() till all
other CPUs implement it.
STM32 L1, F1, F2, F4 supports following modes:
* 7E1, 7E2
* 7O1, 7O2
* 8N1, 8N2
* 8E1, 8E2
* 8O1, 8O2
STM32 L0, L4, F0, F3, F7 supports following modes:
* 6E1, 6E2
* 6O1, 6O2
* 7E1, 7E2
* 7O1, 7O2
* 7N1, 7N2
* 8N1, 8N2
* 8E1, 8E2
* 8O1, 8O2
Use USART_CR1_M1 macro to detect 7-bit support because
even inside one family there could be devices that don't
support 7-bit mode. So just using a family macro is not
enough.
As stated in the datasheets for L0, L4, F0, F3, F7 devices,
data bits can only be changed when UART is disabled (UE=0).
Introduce uart_stop() routine to satisfy this requirement.
STM32 UART adds parity to the MSB of a byte to send. The same
also applies to the received bytes. As a result this bit must
be masked in order to get the pure data.
Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
