.. this allows developers who want to work with both micropython and
circuitpython to enable appveyor on their fork, but not get errors
when pushing circuitpython changes.
In the appveyor configuration for your fork, simply enable the
checkbox "Skip branches without appveyor.yml".
These allow accessing the filesystem label. For instance,
in boot.py, you can set the label on the built-in storage with:
storage.remount('/', False)
storage.getmount('/').label = "NEWLABEL"
storage.remount('/', True)
Users with multiple CIRCUITPY boards may find it desirable to
choose a different label for each board they own.
.. defaulting to off for circuitpython-supported boards, on for others.
.. fixing up the tests that fail when it is turned off, so that they skip
instead of failing
We added a check to make sure the pins are in a high state before
initing the bus. This leads to a friendly error message when someone
forgets to add the pull up resistors to their circuit.
Before this change, `microcontroller.cpu.uid` returned values
where the top 4 bits of each byte were zero, because of
an incorrect bitmask used in this function.
.. the price of this appears to be about 112 bytes of flash and 12
bytes of RAM, according to the stats printed during the build.
It also uses up 4 directory entries (out of 128), but does not reduce
the number of blocks usable for storing file contents.
These are the same items noted in the Adafruit README for Trinket M0
as preventing MacOS indexing.
Closes: #689
The following error occurs when building with gcc 5.4.1 (debian stretch):
common-hal/busio/UART.c:104:83: error: 'sercom_index' may be used uninitialized in this function [-Werror=maybe-uninitialized]
sercom_insts[rx->sercom[j].index]->USART.CTRLA.bit.ENABLE == 0) ||
It may be related to the addition of rx-only UARTs; gcc is unable
to infer the intended relationship between have_tx and sercom_index
being set (I am still not entirely confident of it myself)
Having the `active_read = false` in the background function left
a chance that a new_write occurs before active_read is set to false.
In that case, we'll read the appropriate data rather than write it
and never clear the active write.
Hopefully fixes#655.
