Hi Bob,

Yes, he is waiting after each byte for the EE write done flag (he is
actually using the CCS C write_eeprom function, or whatever it is
called, and he has verified that in the actual generated code it is
checking for that flag to indicate done). The problem is that if he
writes the 177th byte this way, it ALWAYS freezes at that point. He
has to wait an additional 250 milliseconds to continue writing.

Sean


On Fri, Mar 28, 2008 at 12:17 PM, Bob Axtell <engineer@cotse.net> wrote:
> Bob Blick wrote:
>  > On Thu, 27 Mar 2008 15:50:58 -0400, "Sean Breheny" <shb7@cornell.edu>
>  > said:
>  >
>  >> A coworker tells me that he found (by experiment) that if he writes
>  >> more than 167 bytes in rapid succession to the data EEPROM in an
>  >> 18F6627, he must wait at least 250 milliseconds before writing any
>  >> additional bytes. He suspects that the internal charge pump may need
>  >> to recharge or something similar. Microchip says they are not away of
>  >> this problem. The errata don't mention it. The datasheet doesn't seem
>  >> to mention it.
>  >>
>  >
>  >
>  hmmm. Something isn't right here. He needs to wait until each EEPROM
>  byte has been written by
>  the flash unit before he proceeds. Is that happening? otherwise, he
>  might deplete the flash charge
>  pump, the "flash wait" includes charge pump refreshing. Usually about
>  4-5mS per byte.
>
>  --Bob A
>
>
>
>
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