Texas Instruments TMS320F20x/F24x DSP Preliminary, C-Callable Interface to Flash Algorithms, A-29

PRELIMINARY

C-Callable Interface to Flash Algorithms

* passes, the flash is ready to be reprogrammed. The					*
*	operations are performed on the segments of the flash *
* module described by the parameter list:					*
*	1)PROTECT±defines which flash segments to protect.*
*	2)SEG_ST ±start address of segment to be erased. *
*	3)SEG_END±end address of segment to be erased.				*
* To erase flash0 use erase(0xff00,0x0000,0x3fff).					*
* To erase flash1 use erase(0xff00,0x4000,0x7fff).					*
*********************************************************
* CAUTION: Erasing individual segments is not allowed. *
*	The PROTECT parameter should always be set to				*
*	enable all segments, and SEG_ST and SEG_END				*
*	should be set to the end and start address of				*
*	the array to be erased.				*
*********************************************************
_erase:
ERS_PARAMS			.set 3
AR_STACK			.set ar1
AR_PROTECT			.set ar2
AR_SEG_ST			.set ar3
AR_SEG_END			.set ar4
;Begin C Preprocessing
	POPD	*+	;pop return address, push on software stack
	sar	ar0,*+ ;save FP
	sar	ar6,* ;save ar6
	sbrk	#3
	;get arguments and place them properly ± take them from
	;the software stack and place them into their correct
	;positions
	lar	AR_PROTECT,*±
	lar	AR_SEG_ST,*±
	lar	AR_SEG_END,*±
	adrk #ERS_PARAMS+4			;ar1 = next empty point on stack (SP)
;End C Preprocessing
	LDP	#PARMS
	SAR	AR1,SV_AR1		;Save AR1.
	SPLK	#0,ERS_COUNT		;Set erase fail count to 0.
	SPLK	#0,ERROR		;Set algo error flag to 0 (no errors).
**********Put parameters where they belong.**********
	SAR	AR_PROTECT,PROTECT
	SAR	AR_SEG_ST,SEG_ST
	SAR	AR_SEG_END,SEG_END
***********Next Setup to clear flash ************
ers_loop:
	CALL		GCLR	;Clear flash.
	LACL		ERROR	;Check for CLEAR/ERASE error
	BCND		ers_error,neq ;If error, then hard fail.
***********Next Setup to erase flash ************
	CALL		GERS	;Erase flash.
	LACL		ERROR	;Check for CLEAR/ERASE error
	BCND		depletion,neq ;If error, try Flash±write.
	LACL		#1	;Else, no errors erasing.
	B		ers_done	;Restore registers and return.
depletion:
	LACL	ERS_COUNT		;Get erase fail count.

PRELIMINARY Assembly Source Listings and Program Examples A-29