As suggested by Russ Butler in mbed-os issue #7328, and until there is an
implementation of mbed-os issue #4408, we are implementing a workaround
at HAL level to check if there is any ongoing serial transfer (which happens
if HW FIFO is not yet empty).
In case a transfer is ongoing, we're not entering deep sleep and
return immediately.
- serial_init, serial_free and serial_baud function moved from serial_device.c (specific to each STM32 family) to serial_api.c (common STM32 file)
- default baudrate value was hardcoded to 9600
- Value is set now to MBED_CONF_PLATFORM_STDIO_BAUD_RATE for STDIO
- Value is set now to MBED_CONF_PLATFORM_DEFAULT_SERIAL_BAUD_RATE for other use
- UART init will not be stopped before calling serial_baud function
Reworked the serial_format() function for STM32F0x
devices to take the format in the form:
data_bits - parity - stop_bits
E.g. 8 - N - 1
where data_bits exclude the parity bit.
Added a case for 7 bits data as at least the chips
STM32F0x1/STM32F0x2/STM32F0x8 support 7 bits data.
Consolidated serial_format() and uart_init()
functions into a general TARGET_STM serial_api.c
file since the functions are common to all STM targets.
Fixes#4189