If we put no samples into the buffer, then there is no last
sample to fill out hold_value with. (and, in fact, the expression such
as *(uint32_t*)(buffer-4) is outside an allocated region)
Detect this condition, and leave the prior value in place.
This improves clicks heard when pausing and resuming a waveform.
This code is shared by most parts, except where not all the #ifdefs
inside the tick function were present in all ports. This mostly would
have broken gamepad tick support on non-samd ports.
The "ms32" and "ms64" variants of the tick functions are introduced
because there is no 64-bit atomic read. Disabling interrupts avoids
a low probability bug where milliseconds could be off by ~49.5 days
once every ~49.5 days (2^32 ms).
Avoiding disabling interrupts when only the low 32 bits are needed is a minor
optimization.
Testing performed: on metro m4 express, USB still works and
time.monotonic_ns() still counts up
This allows the board to disable the onboard speaker until explicitly
enabled in user code.
Testing performed on a CPB:
* Touching the AUDIO pin with a fingertip no longer generates noise/buzz
* Generating a waveform with `simpleio.tone` produces no sound by default
* When the board.SPEAKER_ENABLE is configured as a digital output and
set True, `simpleio.tone` does produce sound
Note that while guides should include information about SPEAKER_ENABLE, it's
possible that some users who omitted it could view this as a breaking change.
They can fix it by simply adding code similar to
speaker_enable = digitalio.DigitalInOut(board.SPEAKER_ENABLE)
speaker_enable.direction = digitalio.Direction.OUTPUT
speaker_enable.value = True
before using the internal speaker.
Closes: #2258
This PR refines the _bleio API. It was originally motivated by
the addition of a new CircuitPython service that enables reading
and modifying files on the device. Moving the BLE lifecycle outside
of the VM motivated a number of changes to remove heap allocations
in some APIs.
It also motivated unifying connection initiation to the Adapter class
rather than the Central and Peripheral classes which have been removed.
Adapter now handles the GAP portion of BLE including advertising, which
has moved but is largely unchanged, and scanning, which has been enhanced
to return an iterator of filtered results.
Once a connection is created (either by us (aka Central) or a remote
device (aka Peripheral)) it is represented by a new Connection class.
This class knows the current connection state and can discover and
instantiate remote Services along with their Characteristics and
Descriptors.
Relates to #586
.. otherwise, when an AudioPWMOut object was deinitted without being
explicitly stop()ped, it would use up a slot in active_audio[]; the
5th iteration would create a non-working audio object which would just
buzz instead of playing the right thing.
Closes: #2203
@ladyada says:
"having this be adjustable (reference) would be ideal cause you can get
absolute voltages but for now, VCC/4 + 4x matches every other chip :)"
... and indeed doing it this way happens to give a much more steady
reading when using a VCC-referenced resistance, and so many of the simple
things you'd wire up are actually VCC-referenced anyway.
.. based on some tasks I found that caused stuttering:
# Test SD and printing
while True: os.listdir('.')
# Test bulk I/O
while True: len(open('somefile.wav', 'rb').read())
Each of these tasks *WAS* worse and I am improving them in a separate
PR by adding RUN_BACKGROUND_TASKS to them.
This enables the highest level of debug symbols, and all optimizations
except lto that do NOT interfere with debugging, in the view of the gcc
maintainers.
Testing performed: I used a Particle Xenon with a HDA1334 I2S DAC.
I played a variety of mono 16-bit samples at 11025 and 22050Hz nominal
bit rates. With this setup, all the 11025Hz samples sound good.
I tested play, pause, and loop functionality.
During some runs with 22050Hz samples, there were glitches. However,
these may have only occurred during runs where I had set breakpoints
and watchpoints in gdb.
I also tested with a MAX98357A I2S amplifier. On this device, everything
sounded "scratchy". I was powering it from 5V and the 5V rail seemed
steady, so I don't have an explanation for this. However, I haven't
tried it with a SAMD board.
So far, this supports only 16kHz and 16-bit samples with a fixed gain.
This is enough to support the basic functionality of e.g., sensing
ambient audio levels.
The original formulation was because I saw the need to avoid a transition
from playing to stopped exactly when a resume was taking place. However,
@tannewt was concerned about this pause causing trouble, because it could
be relatively lengthy (several ms even in a typical case).
After reflection, I've convinced myself that updating the registers
in this order in resume avoids a window where a "stopped" event can
be missed as long as the shortcut is updated first.
Testing re-performed: pause/resume testing of looped RawSample and
WaveFile audio sources.
Testing performed: installed freshly built .uf2 on a Particle Xenon.
Checked that circuitpython still starts.
Checked that the size of all .uf2 files for nrf builds are plausible.
Aside from memory savings, the performance of Python code (pystone)
increased by about +14%.
However, this adds about 12-16 seconds to each nrf build.
Timings & Sizes (build system: i5-3320M, -j5 parallelism on 4 threads):
Before:
$ make -j5 BOARD=particle_xenon
765004 bytes free in flash out of 1048576 bytes ( 1024.0 kb ).
232076 bytes free in ram for stack out of 245760 bytes ( 240.0 kb ).
68.54user 11.83system 0:34.34elapsed 234%CPU
pystones before: 570
After:
$ make -j5 BOARD=particle_xenon
804284 bytes free in flash out of 1048576 bytes ( 1024.0 kb ).
232072 bytes free in ram for stack out of 245760 bytes ( 240.0 kb ).
71.06user 11.77system 0:46.91elapsed 176%CPU
pystones after: 650
Timings on travis:
Before:
Build feather_nrf52840_express for pl took 55.79s and succeeded
Build feather_nrf52840_express for zh_Latn_pinyin took 3.18s and succeeded
After:
Build feather_nrf52840_express for pl took 62.72s and succeeded
Build feather_nrf52840_express for zh_Latn_pinyin took 19.10s
Closes: #1396
