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LF2401A: Can already CLEARed and ERASEd location be PROGRAMmed in-circuit directly

Pradeep Shinde
Prodigy 640 points


The application requires to 'write' on a few (say just ONE) locations after the QC tests, using embedded programming. Since this device has very small memory size, the embedded programming is quite challenging in terms of memory size management.

To avoid erasing entire sector and to save good number of RAM locations (to hold flash API), is it possible to keep it preconditioned and do only PROGRAM operation? Does this device requires the whole FLASH memory array to be Zeroed, Erased and then Flash programmed at one time?

 

This question is applicable for all F28x families as well.  

Regards,

Pradeep Shinde

DCAT, Dallas 

 

  • 0
    TI__Expert 8500 points

    Pradeep,

    For the F24x, F240x, and F280x any bit that is erased can be programmed. They do not need to erase the whole sector every time they program a bit in the sector. Only if they want to change the state of a bit in the sector from 0 to 1 do they need to erase it, which of course erases the entire sector.

    So, for instance, if the customer programs a sector with a bunch of code and data and say the data in location x is 0xAAAA and location y is 0xFFFF after programming the sector. Without re-erasing the sector the customer can program location y to any value he wants. Also, without re-erasing the sector he can program location x in a manner that only changes bits that are ones to zeros. So, he could program 0x0AA2, but not 0xAAAB. In the latter case he would need to re-erase the sector first or he would get an error. The 28x API reports this as a zero bit error. The 24x and 240x API I think just reports it as a generic erase fail.

    Regards,
    Dave Foley

     

  • 0 in reply to David Foley
    TI__Expert 8500 points

    Sorry, the last sentence above should read "The 24x and 240x API I think reports it as a generic programming fail".

    Regards,
    Dave Foley