SW: Rev H Updates

[hedgecrw]

• [x] Update port and pin mappings for Rev. H
• [x] Separate RTC/SD and Accelerometer into separate SPI buses
• [x] Write LSM6DSOX IMU drivers (and pass-through to LIS3MDL)
• [x] Integrate IMU data retrieval into workflow
• [x] Store/retrieve Node ID into UICR registers
• [x] Initialize STM using retrieved Node ID
• [x] Store network timestamp into RTC if not valid at startup
• [x] Make new sound if RTC not valid at startup
• [x] Make Rev. H the Makefile default
• [x] Test new IMU chip
• [x] Store firmware version in SD card log file header
• [x] Add PRINTF_TO_SD_CARD flag to allow storing debug output on SD card
• [x] Add BLE read characteristic to retrieve current device timestamp
• [x] Periodically scan for networks during ranging to ensure separate networks get merged
• [x] Update Desktop BLE utilities to use Python+Bleak and do away with Noble

[hedgecrw]

nRF will now check that the first two bytes of the UICR-stored Device ID are c0:98. If this check fails, then the device ID has not been properly set and stored in UICR, and the device will notify the user of an error via the buzzer "unhappy error" sound.

[hedgecrw]

If absolutely no device in a network has a valid timestamp, then ranging is pointless. As such, if a device starts up with no valid timestamp, it will not advertise its presence, but it will scan for other devices. If another device exists that does have a valid timestamp, the first device will request the correct timestamp over a BLE characteristic, after which it will set its own RTC clock, then start advertising/operating as normal. In such a way, only devices with valid timestamps will be able to initiate creation of a network or share their times with other nearby devices.