;=====================================================================================================================
; File name:       F2407PWM4.ASM                     
;                    
; Originator:	Digital Control Systems Group
;			Texas Instruments
; Description:                                   
; This file contains source for the Full Compare PWM  drivers for the F2407
; Applicability of these functions is indicated in the Table 1
;=====================================================================================
; History:
;-------------------------------------------------------------------------------------
; 9-15-2000	Release	Rev 1.0
;================================================================================
;                           T A B L E      1
;================================================================================
;     Function Name    |    Applicability
;================================================================================
;                      |      F240 | F241| F243 | LF2402 | LF2406 | LF2407
;                      |           |     |      |        |        |
; F243_PWM_Update      |           |     |      |   Y    |   Y    |     Y 
;================================================================================
;================================================================================
; Routine Name: PWM Update Routine        Routine Type: C Callable
;
; Description:
;  
;  Sine Module
;  
;  C prototype : int F2407_EV2_PWM_Update(PWMGEN *p)
;================================================================================
;
; History:                
; __________________________________________________________________________
; Date of Mod   |                     DESCRIPTION
;   ------------|-----------------------------------------------------------
;               |
;               |
;               |
;               |
;================================================================================
; Definition of the argument structure.
;        struct  _PWMGEN_struct 
;{
; int period, period_mod ; 
; int duty_cycle1, duty_cycle2, duty_cycle3; /* Duty cycle ratios            */
; int (*init)();                                       /* Initialization func pointer  */
; int (*update)();                           /* Update function              */
;
;        
;
;
                .def     _F2407_EV2_PWM_Update
                .include ..\include\x240x.h

_F2407_EV2_PWM_Update:

_F2407_EV2_PWM_Update_framesize .set 0002h

                POPD       *+
                SAR        AR0,*+
                SAR        AR1,*
                LARK       AR0,_F2407_EV2_PWM_Update_framesize
                LAR        AR0,*0+,AR0

;================================================================================
                SBRK       #3          ; Point to ARG1 (in this case period)
                                        ; AR0=(FP0)-3
                LAR        AR2,*        ; get pointer to ARG in AR2.
                
        ; This first arg is the pointer to the structure,
        ; and by LAR AR2,* we get that pointer in AR2. As a result AR2 now 
        ; points to PWMGEN_struct, as defined above.
;--------------------------------------------------------------------------------
                LAR        AR3,#CMPR4   ; point AR3 to CMPR1.
;--------------------------------------------------------------------------------
                MAR        *,AR0
                ADRK       #3           ; Point  AR0 back to FP0.
;--------------------------------------------------------------------------------
                MAR        *,AR2        ; Make AR2 the current ARP.
                                        ; AR2 now points to period.
;--------------------------------------------------------------------------------
                LT         *+           ; Get period in TREG and point AR2 to 
                                        ; the next loc which is period_mod.
;--------------------------------------------------------------------------------
                MPY        *+,AR0       ; multiply by period_mod.
                                        ; also increment AR2 to pt to duty_cycle1
                                        ; set ARP=AR0 -> FP0.
;--------------------------------------------------------------------------------
                SPM        1            ; set appropriate product mode.
;--------------------------------------------------------------------------------
                PAC                     ; ACCH now contains the modified 
                                        ; period (Q0).
;--------------------------------------------------------------------------------
                SACH       *+           ; FR0 now contains the modified period.
;--------------------------------------------------------------------------------
                SFR                     ; divide by 2.
                                        ; =prd.
;--------------------------------------------------------------------------------
                SACH        *           ; FR1 now contains the modified period/2.
                                        ; prd
;--------------------------------------------------------------------------------
                LT        *,AR2         ; Get modified prd in TREG and ARP=AR2.
;--------------------------------------------------------------------------------
                MPY        *+,AR0       ; form prd*duty_cycle1 .
                                        ; inc AR2 to point to duty_cycle2.
                                        ; also ARP=AR0.
;--------------------------------------------------------------------------------

                                        
                PAC                     ; get cmpr1_value in ACCH. (Q0 in ACCH).
;--------------------------------------------------------------------------------
                ADDH        *,AR3       ; ACCH= prd*duty_cycle1 + prd.
;--------------------------------------------------------------------------------
                SACH        *+,AR2      ; store cmpr1_value in CMPR4.
                                        ; also incr AR3 to point to CMPR5,
                                        ; and ARP=AR2.
;--------------------------------------------------------------------------------
                MPY         *+,AR0      ; form prd*duty_cycle2.
                                        ; inc AR2 to point to duty_cycle3.
                                        ; also ARP=AR0.
;--------------------------------------------------------------------------------
                PAC                     ; get cmpr2_value in ACCH. (Q0 in ACCH).
;--------------------------------------------------------------------------------
                ADDH        *,AR3       ; ACCH= prd*duty_cycle2 + prd.
;--------------------------------------------------------------------------------
                SACH        *+,AR2      ; store cmpr2_value in CMPR5.
                                        ; also incr AR3 to point to CMPR6,
                                        ; and ARP=AR2.
;--------------------------------------------------------------------------------
                MPY         *,AR0       ; form prd*duty_cycle3.
                                        ; also ARP=AR0.
;--------------------------------------------------------------------------------
                PAC                     ; get cmpr6_value in ACCH. (Q0 in ACCH).
;--------------------------------------------------------------------------------
                ADDH        *-,AR3      ; ACCH= prd*duty_cycle3 + prd.
                                        ; decrement AR0 to pt to modified period.
;--------------------------------------------------------------------------------
                SACH        *,AR0       ; store cmpr3_value in CMPR6.
                                        ; and ARP=AR0.
;--------------------------------------------------------------------------------
                LAR         AR3,#T3PR   ; point AR3 to T3 period register.
;--------------------------------------------------------------------------------
                LACC        *,AR3       ; get FR0 = modified_period.
;--------------------------------------------------------------------------------
                SACL        *,AR1       ; store modified period in T1PR.
                                        ; ARP=AR1 for return.
;================================================================================
                SPM         0           ; restore compiler's product mode.
;--------------------------------------------------------------------------------
                SBRK        #(_F2407_EV2_PWM_Update_framesize+1)
                LAR         AR0,*-
                PSHD        *
                RET