M918 - L6474 Speed Warning Test

L6474 Find L6474 speed threshold MONITOR_L6470_DRIVER_STATUS

Increase speed until error or max feedrate achieved.

Requires MONITOR_L6470_DRIVER_STATUS.

All tests assume each axis uses matching driver chips.

M918 [E<mm>] [I<current>] [J<0|1|2|3|4|5|6|7>] [K<Kvalue>] [M<microsteps>] [T<current>] [X<mm>] [Y<mm>] [Z<mm>]

`[E<mm>]`	Monitor E with the given displacement (1 - 255mm) on either side of the current position.
`[I<current>]`	Overcurrent threshold. Report current value from driver if not specified.
`[J<0\|1\|2\|3\|4\|5\|6\|7>]`	Select which driver(s) to monitor on a multi-driver axis. `J0`: (default) Monitor all drivers on the axis or E0 `J1`: Monitor only X, Y, Z, E1 `J2`: Monitor only X2, Y2, Z2, E2 `J3`: Monitor only Z3, E3 `J4`: Monitor only Z4, E4 `J5`: Monitor only Z5, E5 `J6`: Monitor only Z6, E6 `J7`: Monitor only Z7, E7
`[K<Kvalue>]`	Value for KVAL_HOLD (0 - 255) (ignored for L6474). Report current value from driver if not specified.
`[M<microsteps>]`	Value for microsteps (1 - 128). Report current value from driver if not specified.
`[T<current>]`	Current (mA) setting for TVAL (0 - 4A in 31.25mA increments, rounds down) - L6474 only. Report current value from driver if not specified.
`[X<mm>]`	Monitor X with the given displacement (1 - 255mm) on either side of the current position.
`[Y<mm>]`	Monitor Y with the given displacement (1 - 255mm) on either side of the current position.
`[Z<mm>]`	Monitor Z with the given displacement (1 - 255mm) on either side of the current position.