Document.

Firmware/mmu.cpp

@@ -450,6 +450,10 @@ void mmu_command(uint8_t cmd)
 	mmu_ready = false;
 }
 
+//! @brief Rotate extruder idler to catch filament
+//! @par synchronize
+//!  * true blocking call
+//!  * false non-blocking call
 void mmu_load_step(bool synchronize)
 {
 		current_position[E_AXIS] = current_position[E_AXIS] + MMU_LOAD_FEEDRATE * 0.1;
@@ -555,6 +559,10 @@ bool mmu_get_response(uint8_t move)
 	return response;*/
 }
 
+//! @brief Wait for active extruder to reach temperature set
+//!
+//! This function is blocking and showing lcd_wait_for_heater() screen
+//! which is constantly updated with nozzle temperature.
 void mmu_wait_for_heater_blocking()
 {
     while ((degTargetHotend(active_extruder) - degHotend(active_extruder)) > 5)

Firmware/ultralcd.cpp

@@ -6996,6 +6996,17 @@ static bool lcd_selftest_fsensor(void)
 	return (!fsensor_not_responding);
 }
 
+//! @brief Self-test of infrared barrier filament sensor mounted on MK3S with MMUv2 printer
+//!
+//! Test whether sensor is not triggering filament presence when extruder idler is moving without filament.
+//!
+//! Steps:
+//!  * Backup current active extruder temperature
+//!  * Pre-heat to PLA extrude temperature.
+//!  * Unload filament possibly present.
+//!
+//! @retval true passed
+//! @retval false failed
 static bool selftest_irsensor()
 {
     class TempBackup