Version 27-Feb-2018 (v3.1.0 r9)

Notes

This release incorporates a number of experimental features and structural changes

Updates and mods

• Integration of @Sebastianv650 Linear Advance v1.5 Details can be found in the Marlin documentation.
• New internal ISR structuring to prevent temperature / fan ISR from stalling stepper and allowing serial RX to be highest priority. CheckRX is no longer needed.
• It is now possible to use the USB interface at 250000 Baud without errors provided the host can handle higher data rates. A firmware rebuild is required to enable capability.
• Add Calibration LCD menu item for optionally disabling XY skew correction.
• XY Skew correction menu item only enabled only when skew is 'perfect' (< 0.1deg).

Bug fixes

• Fix HOME-Z to correct location (calibration point). Fixes dinging the heat-bed after Setup Wizard
• Remove attempted recovery from RX buffer full (just drop chars). This includes a fix to append 'ok' after resend request when line number or checksum error detected. Addresses Prusa-Firmware issue #331
• Use CRITICAL_SECTION in LCD menu and buttons sync.
• Eliminate excessive LCD redraw and flicker.