StateMachine.restart: Restarts the state machine
StateMachine.rx_fifo: Return the number of RX FIFO items, 0 if empty
StateMachine.tx_fifo: Return the number of TX FIFO items, 0 if empty
restart() seems to be the most useful one, as it resets the state machine
to the initial state without the need to re-initialise/re-create. It also
makes PIO code easier, because then stalling as an error state can be
unlocked.
rx_fifo() is also useful, for MP code to check for data and timeout if no
data arrived. Complex logic is easier handled in Python code than in PIO
code.
tx_fifo() can be useful to check states where data is not processed, and is
mostly for symmetry.
The interrupt may have a higher priority than the serial output's
(USB) interrupt and may never make room. This makes prints from
interrupts (like the BLE event calls) best effort for what can be
queued up. The rest of the output will be dropped.
The implementation samples rosc.randombits at a frequency lower than the
oscillator frequency. This gives better random values. In addition, for
an 8-bit value 8 samples are taken and fed through a 8-bit CRC,
distributing the sampling over the byte. The resulting sampling rate is
about 120k/sec.
The RNG does not include testing of error conditions, like the ROSC being
in sync with the sampling or completely failing. Making the interim value
static causes it to perform a little bit better in short sync or drop-out
situations.
The output of uos.urandom() performs well with the NIST800-22 test suite.
In my trial it passed all tests of the sts 2.1.2 test suite. I also ran a
test of the random data with the Common Criteria test suite AIS 31, and it
passed all tests too.
There were a few changes that had broken this example, specifically
2cdf1d25f5 removed file.c from ports/unix.
And (at least for MacOS) mp_state_ctx must be placed in the BSS with
-fno-common so it is visible to the linker.
Signed-off-by: Santeri Paavolainen <santtu@iki.fi>
STM32L476RG MCU of NUCLEO_L476RG board has 6 UART/USART units in total
(USART1, USART2, USART3, UART4, UART5 and LPUART1), but only UART2,
connected to REPL, was defined and available in Python code.
Defined are all 5 remaining UART/USART units including LPUART1.
Signed-off-by: Alexander Ziubin aziubin@googlemail.com
This commit simplifies the customisation of the main MicroPython execution
loop (4 macros are reduced to 2), and allows a board to have full control
over the execution (or not) of boot.py and main.py.
For boards that use the default start-up code, there is no functional
change in this commit.
Signed-off-by: Damien George <damien@micropython.org>
