Texas Instruments TMS320F20x/F24x DSP manual Clear Algorithm, SCLR20.ASM, Segst, Segend, Protect

PRELIMINARY

Assembly Source for Algorithms

A.1.2 Clear Algorithm, SCLR20.ASM

This code is an implementation of the clear (programming) algorithm de- scribed in section 3.2 on page 3-4. Recall that the clear algorithm is identical to the programming algorithm with the data forced to 0000h for all flash address- es.

Memory section: fl_clr

Entry point: GCLR

Parameters to be declared and initialized by the calling code are:

-PROTECT defines the values of bits 8±15 of SEG_CTR during the clear algorithm.

-SEG_ST defines the start address of the flash array to be cleared.

-SEG_END defines the end address of the flash array to be cleared.

Return value: ERROR (@BASE+15); 0 = Pass, 1 = Fail

**************************************************************

**	CLEAR Subroutine	**
*		**
*	TMS320F2XX Flash Utilities.	**
*	Revision: 2.0, 9/10/97	**
*	Revision: 2.1, 1/31/98	**
*		**
*	Filename: sclr20.asm	**
*		**

*Called by: c2xx_bcx.asm or flash application programs. **

* **

*!!CAUTION ± INITIALIZE DP BEFORE CALLING THIS ROUTINE!! **

*			**
*	Function: Clears one or more contiguous segments of		**
*	array 0/1 as specified by the following		**
*	variables.		**
*	SEG_ST	Segment start address	**
*	SEG_END	Segment end address	**
*	PROTECT	Sector protect enable	**
*			*
*	The algorithm used is ºrow-horizontalº, which means that *
* an entire flash row		(32 words) is programmed in parallel.*
*	This method provides better uniformity of programming		*
*	levels between adjacent bits than if each address were		*
*	programmed independently. The algorithm also uses a		*
*	3-read check for VER0 margin (i.e.,the flash location is *

*read three times and the first two values are discarded.)*

* This provides low±frequency read±back margin on *

PRELIMINARY Assembly Source Listings and Program Examples A-5