Cumulative Programming of FLASH

[PaulPorter]

I am busy writing Flash Routines to Program the Flash on a S12xDP512

I have seen the big CAUTION in the manual about Cumulative programming of bits (even though it works) and have some questions around this.
How exactly does one define Cumulative programming of bits?
I know it as programming a byte of say 0xF0, to 0xA0. What about programming 0xA0 to 0xA0? The reason I ask this is because of trying to program a single Byte.
If word has a value of say 0xFFAA, and you want to program 0xAAAA, does this mean you have to erase the whole sector just because I want to  program AA over AA?

I know it works, but the big CAUTION in the data book leave an unsettled feeling in my Tummy.

Regards
Paul

[PaulPorter]

Hi Peg

Thanx for the Link, but it fails to answer my question with regards to programming a byte with the same Data.
If the Address I want to program holds 0xFFAA, why can I not program 0xAAAA to it?
Is programming 0xAA to 0xAA classed as Cumulaive Programming?

Regards

[Alban]

Hello,

The book says you should erase before program.

Yes, programming anything to a cell is programming it, even if the content was the same.

It's like a tombstone. The deeper you carve the rock, the harder it will be to sand the date out !

Alban.

[peg]

Hi Paul,

This technique and its issues I lump together with the "overclocking" of CPU's. Yes it works with varying degrees of success (including very successful) but don't go complaining to anyone when it doesn't work or you break it.

I'm sure you will find this thread interesting:

http://forums.freescale.com/freescale/board/message?board.id=8BITCOMM&message.id=2922