Update README.md

Added the new m-codes to this document.

README.md

@@ -1,8 +1,8 @@
 ==========================
 Marlin 3D Printer Firmware
 ==========================
-[![Coverity Scan Build Status](https://scan.coverity.com/projects/2224/badge.svg)](https://scan.coverity.com/projects/2224)
-
+[![Coverity Scan Build Status](https://scan.coverity.com/projects/2224/badge.svg)](https://scan.coverity.com/projects/2224)
+
 Marlin has a GPL license because I believe in open development.
 Please do not use this code in products (3D printers, CNC etc) that are closed source or are crippled by a patent.
 
@@ -207,15 +207,15 @@ M Codes
 *  M140 - Set bed target temp
 *  M190 - Sxxx Wait for bed current temp to reach target temp. Waits only when heating
 *         Rxxx Wait for bed current temp to reach target temp. Waits when heating and cooling
-*  M200 D<millimeters>- set filament diameter and set E axis units to cubic millimeters (use S0 to set back to millimeters).
+*  M200 D<millimeters>- set filament diameter and set E axis units to cubic millimeters (use S0 to set back to millimeters).
 *  M201 - Set max acceleration in units/s^2 for print moves (M201 X1000 Y1000)
 *  M202 - Set max acceleration in units/s^2 for travel moves (M202 X1000 Y1000) Unused in Marlin!!
 *  M203 - Set maximum feedrate that your machine can sustain (M203 X200 Y200 Z300 E10000) in mm/sec
 *  M204 - Set default acceleration: S normal moves T filament only moves (M204 S3000 T7000) im mm/sec^2  also sets minimum segment time in ms (B20000) to prevent buffer underruns and M20 minimum feedrate
 *  M205 -  advanced settings:  minimum travel speed S=while printing T=travel only,  B=minimum segment time X= maximum xy jerk, Z=maximum Z jerk, E=maximum E jerk
 *  M206 - set additional homeing offset
-*  M207 - set retract length S[positive mm] F[feedrate mm/min] Z[additional zlift/hop], stays in mm regardless of M200 setting
-*  M208 - set recover=unretract length S[positive mm surplus to the M207 S*] F[feedrate mm/min]
+*  M207 - set retract length S[positive mm] F[feedrate mm/min] Z[additional zlift/hop], stays in mm regardless of M200 setting
+*  M208 - set recover=unretract length S[positive mm surplus to the M207 S*] F[feedrate mm/min]
 *  M209 - S<1=true/0=false> enable automatic retract detect if the slicer did not support G10/11: every normal extrude-only move will be classified as retract depending on the direction.
 *  M218 - set hotend offset (in mm): T<extruder_number> X<offset_on_X> Y<offset_on_Y>
 *  M220 S<factor in percent>- set speed factor override percentage
@@ -230,6 +230,10 @@ M Codes
 *  M400 - Finish all moves
 *  M401 - Lower z-probe if present
 *  M402 - Raise z-probe if present
+*  M404 - N<dia in mm> Enter the nominal filament width (3mm, 1.75mm ) or will display nominal filament width without parameters
+*  M405 - Turn on Filament Sensor extrusion control.  Optional D<delay in cm> to set delay in centimeters between sensor and extruder
+*  M406 - Turn off Filament Sensor extrusion control
+*  M407 - Displays measured filament diameter
 *  M500 - stores paramters in EEPROM
 *  M501 - reads parameters from EEPROM (if you need reset them after you changed them temporarily).
 *  M502 - reverts to the default "factory settings".  You still need to store them in EEPROM afterwards if you want to.