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Assembly Source for Algorithms
PRELIMINARY
A-5
Assembly Source Listings and Program Examples
PRELIMINARY
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 ”row-horizontal”, 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 *