ADC device in case of resource re-mapping conflict.
This allows a single ADC device to be used for all channels, which can
free up DMA channels.
For the H7 this makes much more sense because the TEMP and VREF channels
are ALWAYS on ADC3, so using ADC3 for other pins is optimal.
The previous behaviour was to use the first instance for that supported
the pin. This behavour is only used when the configured default DMA
device does not support the pin.
e.g.
```
possible.
```
The above config would no-longer use ADC1 for anything, as ADC2 and ADC3
can satisfy all the ADC requirements.
The H730 is a value-line CPU, similar to the H723/H725, but with only
128kb RAM.
The FC firmware code is designed to RUN from external flash in MEMORY
MAPPED mode, via OctoSPI. Use of ITCM/DTCM advised for core loops, like
PID control.
A bootloader is required to enable memory-mapped mode and jump to the
firmware, similar to how EXST bootloader system works.
Config storage is not part of this commit and is a problem when using a
single flash chip in memory mapped mode because the CPU can't run
read/write routines from the flash chip while writing to the flash chip.
Until flash read/write routines are updated the solution requires either
a second flash chip on an SPI interface, or the use of an SD card for
config storage.
Additional commits will support read/write of config to the code/data
storage flash chip to enable cheap and space efficient single-flash-chip
FC solutions.
Squashed commits:
STM32H730 - Workaround issue with 2GB `.elf` files being created.
STM32H730 - Reduce firmware size to 1MB.
STM32H730 - Add USB HS configuration.
STM32H730 - Add ADC internal tag mappings.
STM32H730 - Update all ADC mappings based on the referenced ST
documentation. Add the VBAT channels.
STM32H730 - Fix DMA continuous requests.
STM32H730 - Fix ADC_INTERNAL confusion.
STM32H730/G4 - Disambiguate use of ADC_CHANNEL_INTERNAL_FIRST_ID.
STM32H730 - Fix documentation reference.
STM32H730 - Add DMA request mapping for ADC3.
STM32H730 - Explicitly set the ADC clock.
STM32H730 - Configure PLL2 speeds correctly.
* Tested with Ultrafast 64GB SanDisk SDXC card.
STM32H730 - Use 50Mhz clock for SDXC cards.
* Tested with SanDisk Ultra 64GB. 100Mhz clock gave CRC errors.
STM32H730 - Ensure USB has a lower NVIC priority than the SDMMC card
reads.
If it's higher, 0, then the SDMMC's DMA IRQ handler doesn't get called
when handing USB MSC storage reads.
STM32H730 - Support CPU name in CLI.
STM32H730 - Rebuild when linker scripts changes.
