The picodvi PR #7880 switched the saved word to the watchdog
register since it reworked the RAM layout. This works for
reset_into_safe_mode because the watchdog scratch registers are
preserved by soft resets. They *aren't* preserved for pressing the
reset button. So it broken manual safe mode. Switch back to using
RAM to store the saved word but use the pico-sdks "uninitialized"
designation instead of a fixed location.
Also fixes USB host feather status neopixel by setting the power
pin.
By pausing audio during flash writes, the worst screeching of #8121
is avoided. I don't consider this a full fix, but it greatly improves
the by far most common scenario in which the problem occurs.
Tested on rp2040 prop feather with a midi synth playing arpeggios. When
writing to the flash e.g., with
```
dd bs=512 count=32 if=/dev/zero of=/media/jepler/CIRCUITPY/boop
```
the audio goes "tap tap tap tap" during the flash write instead of the
squawking.
This isn't a 100% fix; it will still glitch out, including during USB
enumeration which must be taking a long time without servicing background
tasks. Add a delay if not usb-connected at startup ameliorates this
greatly.
This adds a check to make sure that SDA and SCL are in a sane condition
before starting any I2C operation. If they are not it tries to rectify it,
and then returns an error code if unable to do so.
on specific SCK/MOSI/MISO pins, the `common_hal_busio_spi_construct`
method always skip miso pins which will lead to a `invalid pin`
exception when SPI initilized
In my testing, the feather bluefruit can do 12 voices at 48kHz!
This is a simple case (no LFOs, no ring modulation) so other situations might
require a lower sample rate, fewer voices, or both.
The sound is a little artifacty & low-fi but I think that's down to the speaker
& use of PWM instead of I2S.
and re-organize so that esp32 s2/s3 don't do as much at reset
.. it's not necessary (because most data is in esp-idf managed memory)
and doing this saves me from having to debug why reconstruct isn't working
properly on that platform.
This needs to be tested on other platforms again before being merged!
