Another reduction of -48 bytes can be had if the fine calculation
step is skipped. The worst difference compared to the old reference
code with my calibration values in the 0° to 60° was 2°C,
and the difference at 25°C is 1°C.
The final size decrease for non-full builds like Trinket M0 is 268
bytes.
Perform most arithmetic with scaled integer values.
For my calibration values
```
const uint32_t NVMCTRL_TEMP_LOG[]={0xfc05511e, 0xcc7ac0f7};
```
the maximum difference between the old and new calculation is 0.50°C.
The difference is smallest (0.13°) at 25.87°C in the old scale.
This reduces mcu_processor_get_temperature from 568 bytes to 348 bytes
(-220 bytes)
This tweaks the RMT timing to better match the 1/3 and 2/3 of 800khz
guideline for timing. It also ensures a delay of 300 microseconds
with the line low before reset.
Pin reset is now changed to the IDF default which pulls the pin up
rather than CircuitPython's old behavior of floating the pin.
Fixes#5679
Initially enabled for samd51, this enables reading raw flux data as well
as DOS/MFM formatted media.
This is only the low-level code for reading & decoding flux pulses from a floppy drive.
high level details will live in a Python library.
adafruit-circuitpython-floppy will take care of details like stepping
from track to track, etc.
The port is free to return NULL for any/all of these, and the caller has
to check.
This will be used in the floppy code, because aside from getting the
registers, it looks like all is independent of MCU.
This targets the 64-bit CPU Raspberry Pis. The BCM2711 on the Pi 4
and the BCM2837 on the Pi 3 and Zero 2W. There are 64-bit fixes
outside of the ports directory for it.
There are a couple other cleanups that were incidental:
* Use const mcu_pin_obj_t instead of omitting the const. The structs
themselves are const because they are in ROM.
* Use PTR <-> OBJ conversions in more places. They were found when
mp_obj_t was set to an integer type rather than pointer.
* Optimize submodule checkout because the Pi submodules are heavy
and unnecessary for the vast majority of builds.
Fixes#4314
