INT E0 - PCROBOTS v1.41 - "REGISTER_Y" - SELECT AUTOMATIC Y POSITION UPDATES
	AX = 002Eh
	BX:CX -> Y word variable
Return: AX = status (0001h OK, 0000h problem with address)
Note:	after this call, PCROBOTS will automatically update the specified
	  word whenever the robot moves
SeeAlso: AX=002Dh