;===========================================================================
; File Name:	field_prof.asm			      
;
; Module Name: 	FLELD_PROFILE	
;
; Initialization Routine: FLELD_PROFILE_INIT
;
; Originator:	Digital Control Systems Group
;			Texas Instruments
;
; Description:	This module generates the output command of rotating d-axis 
;               stator current for a specific input command of speed reference 
;		        This is used for variable speed implementation of the vector
;               control of AC induction motor drives.
;
; Note that this field profile has two regions.
; Region 1: Constant id_out at below rated speed.
; Region 2: Inversely proportional decreasing id_out at higher rated speed
;           (field weakening operation).  
;
;		          		|~~~~~~~~~~~~~~~~~~~~~~~|
;				        |           		    |
;	 spd_ref_fp o------>|Q15  FLELD_PROFILE  Q15|----->o  id_ref_fp
;			          	|	        	        |
;				        |_______________________|
;
; Target dependency:	C2xx core only
;
;=====================================================================================
; History:
;-------------------------------------------------------------------------------------
; 11-19-2000  Release	Rev 1.0	 
;===========================================================================
;(To use this Module, copy this section to main system file)
;		.ref	FLELD_PROFILE, FLELD_PROFILE_INIT		;function call
;		.ref	spd_ref_fp			                    ;Input
;		.ref	id_ref_fp				                ;Output
;		.ref	spd_1, id_1            					;Parameters
;===========================================================================
;Module definitions for external reference.
		.def	FLELD_PROFILE, FLELD_PROFILE_INIT		;function call
		.def	spd_ref_fp			                    ;Input
		.def	id_ref_fp				                ;Output
		.def	spd_1, id_1            					;Parameters
;===========================================================================
		.include	x24x_app.h

;---------------------------------------------------------------------------
;User configurable default parameter values
;ID_1_		.set	2500h		; 1HP Maximum value of d-axis stator current   (Q15)
ID_1_		.set	1500h		; 1/4HP Maximum value of d-axis stator current   (Q15)
SPD_1_		.set	4000h		; High (rated) speed point on profile      (Q15)
;---------------------------------------------------------------------------------
				
spd_ref_fp  .usect	"field",1	
id_ref_fp  	.usect	"field",1   	
spd_abs     .usect	"field",1
spd_1    	.usect	"field",1  	
id_1		.usect	"field",1
field_tmp1  .usect	"field",1

;----------------------------------------------------------------------
FLELD_PROFILE_INIT:
;----------------------------------------------------------------------						
		LDP		#spd_1					

		SPLK	#SPD_1_, spd_1
		SPLK	#ID_1_, id_1
		
		RET
;----------------------------------------------------------------------
FLELD_PROFILE:
;----------------------------------------------------------------------					
   		SPM		0 				; Reset product mode 
		SETC	SXM				; Set sign extension mode
		SETC	OVM				; Set overflow mode
		
		LDP		#spd_ref_fp
        LACC	spd_ref_fp		; ACC = spd_ref          (Q15)	
        ABS						; ACC = |spd_ref|        (Q15)
        SACL	spd_abs			; spd_abs = |spd_ref|    (Q15)
; Check |spd_ref| is in between 0 and spd_1 ?
		SUB		spd_1           ; ACC = |spd_ref| - spd_1   (Q15)
		BCND	FIELD_PROF1,LT 	; Branch to FILED_PROF1 if |spd_ref| < spd_1
        B		FIELD_PROF2     ; Branch to FILED_PROF2 if |spd_ref| >= spd_1
FIELD_PROF1
		LACC	id_1          	; ACC = id_1       (Q15)
		SACL	id_ref_fp		; id_ref = id_1    (Q15)
 		B		FIELD_END				
FIELD_PROF2
		LT		id_1			; TREG = id_1          (Q15)
		MPY		spd_1			; PREG = id_1*spd_1    (Q30)
        PAC						; ACC = id_1*spd_1     (Q30)
        SACH	field_tmp1,1	; field_tmp1 = id_1*spd_1     (Q15)
        LACC	field_tmp1,15	; ACC = id_1*spd_1 left shifted by 15 (id_ref_fp=Q15)
		RPT		#15				; Repeat SUBC 16 times        
		SUBC	spd_abs      	; Dividing (id_1*spd_1)/|spd_ref|  
        SACL	id_ref_fp		; id_ref_fp = (id_1*spd_1)/|spd_ref|    (Q15)
FIELD_END
		RET