However, because this doesn't follow the datasheet recommendations, you can no longer rely on all the promises in the datasheet. I hear rumors that such non-sanctioned activity causes data retention time and endurance to suffer, because of program disturb, over-programming, charge trap, effects similar to DRAM row hammer , etc. Partial-page programming, non-sequential pages programming within the block, excessive read per block without erase as well as non-equal number of read operation within a single block increase number of the read disturb errors.
This bit error may occur either on the page being programmed or on another page in the block. Bias voltage conditions in the block during the page programming can cause a small amount of current to tunnel into nearby memory cells. Repeated partial page programming attempts will continue to aggravate this condition. This condition is made worse by random programming in the block and by applying multiple partial writes to the pages.
It is highly likely that the programming software that you are using is already writing the "required" bytes. It "appears" like its is giving you the capability of writing from one to bytes, but I suspect that what it is doing is OR-ing the byte s you want with a "mask" of "FF.
If a checksum is written outside of your control, then, most likely, an invalid checksum will be created when you write another byte into a previously written segment. The implications of this, is chip dependent. If your programming software, does not do the "OR-ing," you can do it yourself. Clear a byte segment, write the byte s into the correct position s , OR with a byte mask of FFs, and write the segment to the desired page.
Whether either method works with any particular chip, can be easily determined by you. Write to the first bytes, write to the second bytes, verify that the first bytes are NOT "messed up"! Sign up to join this community.
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New Member. Flash Write: Realy need erase before? Hi everybody! I'm intend do use flash memory from PIC18F45K20 for store a huge amount of data bytes , maybe once in a week or more longer. My question is: I realy need to erase the block of memory before write on it or I can just do the write process? Best Regards, Rodolfo. Super Member. RE: Flash Write: Realy need erase before?
Remember when using such method there is also a "cummulative write time" which should not be exceeded with time spend writing between two erase cycles.
Jan Kesten said: at locations which are not written already or to simple set some bits to zero you can do this without the need to erase the entire segment. Site Search User. Mentions Tags More Cancel. Ask a related question What is a related question? A related question is a question created from another question. When the related question is created, it will be automatically linked to the original question. Ask a new question Ask a new question Cancel. Tags More Cancel. Share More Cancel.
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