Added ADC/DAC resolution to $pinstate command, changed reported values to integer for ADC/DAC devices and float formatted for PWM devices.
Numeric settings can now be set via G65P1Q<n>S<value>, <n> is the setting number, <value> is the new value.
Changed alarm code for Modbus exceptions (communication errors) from 14 to 19.
Refactored MPG stream code to allow plugins to hook into MPG streams (via event handler).
Added _free memory system parameter, returns value in KBytes or -1 if not available from driver.
Changed basic stream data type from char to uint8_t, added HAL function and core API for releasing/closing UART streams.
Added named parameters _probe_state and _toolsetter_state. Both return -1 if state is not available.
These may return incorrect values initially so use with care.
Some low-level ioport improvements, added definition for virtual pins/ports.
Deprecated direct access to number of the different ioport ports in hal.port struct, use ioports_unclaimed() instead.
Added code guards in order to free some memory for STM32F103 variants with 128K flash.
Changed Stop (0x19) real-time command behaviour, active tool offset and coordinate system will now be kept. Ref. issue #610.
Fixed incorrect comment string passed to passed to grbl.on_gcode_comment event.
Added generic redirector for temporarily changing input stream to read from a file. Supports nesting.
