One can't use pthread calls in a signal handler because they are not
async-signal-safe (see man signal-safety). Instead, sem_post can be used
to post from within a signal handler and this should be more efficient than
using a busy wait loop, waiting on a volatile variable.
This header is deprecated as of mbedtls 2.8.0, as shipped with Ubuntu
18.04. Leads to #warning which is promoted to error with uPy compile
options.
Note that the current version of mbedtls is 2.14 at the time of writing.
The machine.sleep() function can be misleading because it clashes with
time.sleep() which has quite different semantics. So change it to
machine.lightsleep() which shows that it is closer in behaviour to
machine.deepsleep().
Also, add an optional argument to these two sleep functions to specify a
maximum time to sleep for. This is a common operation and underlying
hardware usually has a special way of performing this operation.
The existing machine.sleep() function will remain for backwards
compatibility purposes, and it can simply be an alias for
machine.lightsleep() without arguments. The behaviour will be the same.
If MICROPY_PERSISTENT_CODE_LOAD or MICROPY_ENABLE_COMPILER are enabled then
code gets enabled that calls file reading functions which may be disabled
if no readers have been implemented.
To fix this, introduce a MICROPY_HAS_FILE_READER variable, which is
automatically set if MICROPY_READER_POSIX or MICROPY_READER_VFS is set but
can also be manually set if a custom reader is being implemented. Then
disable the file reading calls if this is not set.
For architectures where size_t is less than 32 bits (eg 16 bits) the args
must be casted to uint32_t so the left shift will work. For architectures
where size_t is greater than 32 bits (eg 64 bits) this new casting will not
lose any bits because the end result must anyway fit in a uint32_t.
This aligns more closely with the hardware, that there are two, fixed HW
SPI peripherals. And it allows to recreate the HW SPI objects without
error, as well as create them again after a soft reset.
Fixes issue #4103.
In order to suit the more common 800KHz by default (instead of 400KHz), and
also have the same behaviour as the esp8266 port.
Resolves#4396.
Note! This is a breaking change. Anyone that has previously used the
NeoPixel class on an ESP32 board may be affected.
The original behaviour of open-drain-high was to use the open-drain mode of
the GPIO pin, and this seems to make driving a DHT more reliable. See
issue #4233.
The ESP IDF system already provides a math library, and that one is likely
to be better tuned to the Xtensa architecture. The IDF components are also
tested against its own math library, so best not to override it. Using the
system provided library also allows to easily switch to double-precision
floating point by changing MICROPY_FLOAT_IMPL to MICROPY_FLOAT_IMPL_DOUBLE.
So that the user can explicitly deactivate UART(0) if needed. See
issue #4314.
This introduces some risk to "brick" the device, if the user disables the
REPL without providing an alternative REPL (eg WebREPL), or any way to
reenable it. In such a case the device needs to be erased and
reprogrammed. This seems unavoidable, given the desire to have the option
to use the UART for something other than the REPL.