once hardware flow control is enabled, rts should only be initialized
after the uart is enabled by setting the UE flag. This is stated in the
stm32f4 errata.
in uart_poweroff the peripheral should be disabled through the register
instead of just disabling the peripheral clock. In uart_poweron the
peripheral should be enabled after enabling the clock.
Not explicitely disabling the peripheral causes some bad signals on the
uart line sometimes.
USART_CR1_M combines both USART_CR1_M0 and USART_CR1_M1 macros
affecting bits 12 and 28 on 7 data bits capable UARTs. Whereas
for other UARTs USART_CR1_M macro affects only bit 12.
This patch fixes wrong data bits usage on 7 data bits capable
UARTs with using USART_CR1_M0 macro for modes 8-E-x and 8-O-x.
It also simplifies bits unsetting as USART_CR1_M macro clears
all data bits related bits for both UART types.
Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
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>
Due to the stdio getting called after periph_init the uart may send before initialized.
This adds a simple check so the uart does not get into a locked-up state.
