With clock bypass enabled the attached SD card is clocked at the maximum
48MHz. But some SD cards are unreliable at these rates. Although it's
nice to have high speed transfers it's more important that the transfers
are reliable for all cards. So disable this clock bypass option.
This way the UART REPL does not need the MicroPython heap and exists
outside the MicroPython runtime, allowing characters to still be received
during a soft reset.
Auto-detection of the crystal frequency is convenient and allows for a
single binary for many different boards. But it can be unreliable in
certain situations so in production, for a given board, it's recommended to
configure the correct fixed frequency.
Configuration for the build is now specified using sdkconfig rather than
sdkconfig.h, which allows for much easier configuration with defaults from
the ESP IDF automatically applied. sdkconfig.h is generated using the new
ESP IDF kconfig_new tool written in Python. Custom configuration for a
particular ESP32 board can be specified via the make variable SDKCONFIG.
The esp32.common.ld file is also now generated using the standard ESP IDF
ldgen.py tool.
When the ESP IDF builds a project it puts all separate components into
separate .a library archives. And then the esp32.common.ld linker script
references these .a libraries by explicit name to put certain object files
in iRAM.
This patch does a similar thing for the custom build system used here,
putting all IDF .o's into their respective .a. So a custom linker script
is no longer needed.
ISR's no longer need to be in iRAM, and the ESP IDF provides an option to
specify that they are in iRAM if an application needs lower latency when
handling them. But we don't use this feature for user interrupts: both
timer and gpio ISR routines are registered without the ESP_INTR_FLAG_IRAM
option, and so the scheduling code no longer needs to be in iRAM.
The new compile-time option is MICROPY_HW_USB_MAX_POWER_MA. Set this in
the board configuration file to the maximum current in mA that the board
will draw over USB. The default is 500mA.
The new compile-time option is MICROPY_HW_USB_SELF_POWERED. Set this
option to 1 in the board configuration file to indicate that the USB device
is self powered. This option is disabled by default (previous behaviour).
It can be that LSEON and LSERDY are set yet the RTC is not enabled (this
can happen for example when coming out of the ST DFU mode on an F405 with
the RTC not previously initialised). In such a case the RTC is never
started because the code thinks it's already running. This patch fixes
this case by always checking if RTCEN is set when booting up (and also
testing for a valid RTCSEL value in the case of using an LSE).
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 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.
Without the static qualifier these objects will be kept by the linker even
if they are unused. So this patch saves some RAM when these features are
unused by a board.
If there are many short reads to a socket in a row (eg by readline) then
releasing and acquiring the GIL each time will give very poor throughput.
So first poll the socket to see if it has data, and if it does then don't
release the GIL.
Otherwise, if multiple threads are active, printing data to the REPL may be
very slow because in some cases only one character is output per call to
mp_hal_stdout_tx_strn.
On MCUs other than F4 the ORE (overrun error) flag needs to be cleared
independently of clearing RXNE, even though both are wired to trigger the
same RXNE IRQ. In the case that an overrun occurred it's necessary to
explicitly clear the ORE flag or else the RXNE interrupt will keep firing.
Otherwise IRQs may not be enabled for the user UART.irq() handler. In
particular this fixes the user IRQ_RXIDLE interrupt so that it triggers
even when there is no RX buffer.
The new option MICROPY_HW_SDCARD_MOUNT_AT_BOOT can now be defined to 0 in
mpconfigboard.h to allow SD hardware to be enabled but not auto-mounted at
boot. This feature is enabled by default to retain previous behaviour.
Previously, if an SD card is enabled in hardware it is also used to boot
from. While this can be disabled with a SKIPSD file on internal flash,
this wont be available at first boot or if the internal flash gets
corrupted.
